Bitcoin Forum

Im in the states.. Im just wondering what everyone's power limit is at?

Im not sure what i got goin on.. i may end up calling an electrician before more mining gear gets here...


Anyone know the cost of getting an electrician to upgrade you to 30 - 50amp?  Whats everyone's experience?

I personally am running a 20 amp fuse, not breaker. I have an old house, like 1952, and live in the Southern US.

As far as an electrician and wiring, that depends on a number of factors. Local codes, how big your place is, max amps your house can pull, and 500 more.

I don't have that much mining gear now. Only running a 1000w and 750w PSU now.

Well I've been thinking about this also. 

I used this calculator to calculate my wattage.:  http://www.supercircuits.com/resources/tools/volts-watts-amps-converter

The one I've seen, for instance, indicate 1050 watts, so they are pulling about 8.75 amps on standard 110-120 V AC current.  That shouldn't overload a circuit, although depending on what else is on it, you might have to be careful about where you plug it in or you'll be dumping the circuit if something else kicks in.  You'll have to check your breaker panel to find a decent circuit to run it from.  Bottom line, I'd run it off a 20 amp and limit what else is running on that circuit if at all possible.

you will cut your energy consumption if you can run on 220-240, which will depend on your unit.  That's monayz in the bank, so you may want to call an electrician to run you a dedicated circuit for that purpose.  Cost?  Dunno.  That will depend on a lot of things.  Among them:

1.  Will your panel accept this sort of breaker
2.  Does your panel have room for this breaker
3.  How long is the run from the panel to where you want to run this thing

etc., etc., etc.  Bottom line if you want to do this you'll probably have to have an electrician out to give you an estimate.

OK, you are confusing the capacity of individual lines in the house with the total incoming service.

The two have only a limited relationship.

Depending on when your house was built and depending on when and if there have been upgrades to your electrical service, you will have pretty much have 60, 100 or 200 amp service.

You'll have to contact your local power company to find out.

Now this is what my partners and myself have done.

A few years back in the height of the foreclosure crisis, we each bought nifty-fifties ranch style homes with basements.  We moved the furnace/AC and hot water tanks out of the basements to ground floor or attic locations, leaving the entire basements essentialyl free span except for the beam supporting posts.  This was not originally done with crypto mining in mind but it is going to work out well for it.

In my area we can get 400 amp incoming service, 88,000 watts, brought in by the utility company and the wiring upgrade cost around USD $2.5K per home.

We can run a shit ton of miners with 88,000 watss capacity and still run the entire home.

We had the electrician who had pulled the permit to hook up the existing house wiring to the new breaker box and weatherhead, leaving the rest of the breakers not hooked to anything, telling the city inpspector that those were for future use and we'd get back to him.

About three minutes after the inspector signed off on the job I was busily running new circuits in preparation for mining as we are using these three locations for the upcoming mining farm offering; Lost Dutchman Mining.

Now in your case, remember that a single wall socket is only good for about 2500 watts max, so if you are going to run a bunch of miners, you're going to have to have a lot of 30 amp lines coming off your breaker box.

To do what you want to do you need to contact a couple of local electicians and get competitive bids as such bids could vary wildly but hit me up any time via PM and I'll give you whatever advice I can.

Thanks for reading and best wishes to you!

My $.02.

:)

Can you say... grow house? :-)

LOL!

Been there, done that about 30 years ago!

Actually we stirpped the basements for the storage of our antique and classic cars, what with all of us being total gearheads.

To do gowhouses would require lots of insulation but that is another story...................

:)

:-)  Were you going to build elevators into the garage to get the cars down to the basement? Also, what are you planning to be your mining hardware platform? I will be expanding out to a small 10 TH/S farm the middle of next year and I am captivated by the folks that go really big.

No, the houses all have basement garages with overhad doors which we have closed up now with proper insulation, etc.

We are going to do primarily altcoin mining with at least some ASIC rigs, providing that such equipment is available in a time frame which ensures profitability before difficulty becomes to high.  We are in negotiation with several ASIC manufacturers to provide us with at least prototypical equipment for real-world live testing but the outcome of those negotiations remain to be seen.  Tell you this though, anyone who will work with us is real and we will promote them in return.

Scrypt equipment can be constructed from readily available components and the Scryptcoins converted to Bitcoins if desired, so that is the road we are going to follow with Lost Dutchman Mining.

If someone orders a given hash rate the lag time is less than two weeks from cleared funds to active mining and most of that is shipping time of the components and assembly.

We can also get additional 400 amp services into the houses at residential rates by operating home-based businesses for which we will be licenced.

Anyway, long day here in Brownbackistan; the new name for Kansas since we now have an idiot for a governor.

Check you later!

:)

Hey thanks for chiming  in everyone!


Lostdutchman you are right.. i was confusing the capacity of individual lines with the total incoming!
( i clearly have more homework to do)

btw, holy crap you got a crazy setup.. I wish i had a basement, it would be on..

 my house was made in 85 and its about 2500 square feet.... this is my panel!
https://i.imgur.com/KGP6Zfu.jpg


 

bedrooms and family room labeled 15 and the garage is 20. I have a one labeled dryer that says 30.

Hopefully i can add or upgrade the garage or the bedrooms without replacing the whole panel or paying thousands to have a wiring change.

Im thinking about setting up shop in the garage but i work from home and thats my office so i dont think i can stand the noise.

I guess right now the first rig will be fine.. @2100w in either the garage or bedroom.. ( maybe i can wheel it over to the garage from the bedroom when i sleep lol )


I planned on sucking down about 2100watts to start and then gradually bring in more replica rigs adding 2100watts each!
Im not going too nuts yet.. but i would like to get up to 15-20mhs if i could depending on any hurdles that may arise. Im eying a couple alt coins i want to mine.. so ill be splitting the task between the two.. 

Thanks again for the input everyone .. im going to do what lostdutchman suggested and ask the power company what amp service im getting. After that hopefully i can get the first rig setup and start thinking about a long term power plan. Im waiting for my gear to come in so i wont get started till the 13th or so..






 

Hey, man, we are 100% cool and thank you for your kind response!

I think from the looks of your box that you got 100 amp service but check it out.

Yeah, I have gone maybe crazy over mining but to use a trite phrase, it is "the wave of the future" for at least a while and long enough to provide myself, my associates and anyone who chooses to do business with us with comfortable retirements.

Hit me up any time and I'll do what I can to help you.

;)

You can't make a statement like that.  It depends on the outlet.  Continual loads should be derated 20%.

120V 15A = 1440W (120*15*0.8 )
120V 20A = 1920W (120*20*0.8 )
 
240V 15A = 2880W (240*15*0.8 )
240V 20A = 3840W (240*20*0.8 )
240V 30A = 5760W (240*30*0.8 )

There are 40A and 50A outlets but they are expensive and it is hard to find cost PDUs which match.  If you are running a custom line have an electrician (or DIY if you are competent) install a 30A breaker, 10AWG branch line, and a NEMA L6-30R outlet (240V, 30A, locking).  Then pickup a cheap used datacenter PDU with a NEMA L6-30P plug.  Good for a solid 5.76KW.  Better yet install two and you are covered for 11.5KW.  That should be good for 14 TH/s or rigs @ 0.8 J/GH.  Beyond that your largest challenge will be cooling not power.  

You are correct but I was referring to the average residential installation, which is what the OP is dealing with.

Thank you for your input and advice.

Many people will plug in a power strip to an ordinary outlet, hook up a toaster, a coffee pot, a waffle iron, a microwave, a small TV for the ktichen and then wonder why the breaker trips or the house burns down and we don't want any of that!

Thanks again for you post as it contains very important information!

My $.02.

:)

This is excellent advice. I am moving to a new home in a few weeks and that is the 2nd modification I am having made to the basement. 2x 30AMP 240V circuits.

DeathAndTaxes! Thank you for your input its very much appreciated! You guys seem to have a serious grip on electricity !!


if im not mistaken 120v is for the USA and 240v is for EU. So on the list you made the second one applies to me right, im in the states..?

120V 20A = 1920W  120*20*0.8

Do you mean: 2400w


Does that mean on one socket i cant go above 1920w 2400w! Is there some kind of ettiqute in terms of leaving some cushion or can you go pedal to the medal and use all the juice it can give?



I take it this is for sockets in EU and not US, same with the connector on the pdu? ( NEMA L6-30R )

You can have 240 installed in homes in the USA as well. This is what electric dryers run on.

Oh i see!! Forgive my ignorance..

D&T, im stealing this.

Just checked the panel box in basement... I've got room for 9 more breakers!

No.  In the US a continual load can't use more than 80% of the circuits capacity.  I just realized the 0.8 got changed into a smiley so I fixed that.

So in the US a 120V, 20A circuit is rated for 2400W PEAK however continual loads should not exceed 80% of that  2400W * 0.80 = 1920W.

Higher current = higher heat.  House wiring is sized under the assumption that the load will vary and that is easier to cool.  Now you "can" pull 2400W from a 20A breaker continually but that would be a violation of the NEC as the wire would be under greater resistance that intended for continual use and the breaker won't trip.  In theory if the wiring was substandard, or faulty, or corroded due to age it "could" cause a fire.  Now the risk is probably pretty low but the Electrical Code is designed to be conservative because it involves people's lives.  

I have no knowledge of European standards, outlets, or ratings but current, resistance, heat are pretty much universal so the same general concepts still apply.


Other than the 20% derate for continual loads, yes.  So the 1920W not the 2400W is the correct figure if you are running a load continually (like a 24/7 miner).


No.  NEMA is Noth American Electrical Manuacturers Association.  They are all US outlets.  The NEMA 5-15 is the "standard" US wall outlet.  The NEMA L6-30 is a 30A, 240V outlet which uses a locking connector.


Here is an example I just like the photo not trying to give this seller any business:
http://www.ebay.com/itm/APC-AP9571-1U-Rackmount-PDU-208V-24A-12-C13-Outlets-/261343426014?pt=US_Power_Distribution_Units&hash=item3cd94835de

There are tons and tons and tons of this PDU (PDU = fancy name for datacenter high current power strip).  APC probably makes a couple millions so there are always used ones on ebay for cheap.

It has a NEMA L6-30P plug.  The plug is rated for 30A but you will notice in the description it says 24A.   Why?  NEC requires that continual loads be derated 20%.  30A * 0.8 = 24A.  24A * 240V = 5760W.

Note the official specs are 208V because they were designed for datacenters but they work fine at 240V as well.  It is simply a "power strip" with circuit breaker there are no electronics which require a specific voltage.  


So:
30A breaker ------> 10 AWG wiring -------> NEMA L6-30R outlet ------> AP9571 (w/ L6-30P plug).
You now have 5760W of mining power, done right and safe.  The PDU gives you 12 outlets so no matter how your rigs are configured you are good to go.

I ran 12KW of GPUs off three of these.  :) 

This is great info thanks for the writeup D+T!

Oh, don't plug 110 devices into 220 power.

What?

You don't like fireworks and the smell of fried insulation?

You're no fun at all!

;)

Well, blue smoke is pretty fun....

DeathAndTaxes !!


Thanks for clearing that up and going into detail! I should have figured there was a cushion required.. hence the 1920w.

As you can see im not the only one who's benefiting from your feedback! Thanks for being so generous with your knowledge.. somehow i think your just being yourself but i appreciate it nonetheless!!!
 



 5760W of mining power, done right and safe.  ( FTW!!! )  

:)

A home wiring book will explain all this, it's really not as complicated as it seems.

If you stick to 120v....:

Remember that anybody might have put either a 15 amp or a 20 amp breaker on the same 120v circuit, but that circuit might be more appropriate for 15 than 20, when the size of wire and/or ratings of outlets are taken into consideration. So the existing breaker size doesn't necessarily give you the information you need if you are thinking about constantly running the circuit at or near max.

I would have 12 ga. wire on a 120v 20 amp circuit that I was going to push hard, and not spindly smaller stuff, and I would aim for that circuit to be dedicated to a single outlet.  That's ideal.  (Obviously you need 10 ga if you move up to 240v.)

What else you have on the same circuit matters!  You can't run max load on one outlet while another outlet on the same circuit controls, say, the dishwasher... or you plug a vacuum cleaner into it!  If you do that, then you may pop the circuit.

Space on your breaker board doesn't necessarily mean you have that much unused overhead in your service.  What matters is the load you put on the overall house service - all your electric demand put together compared to your total house service.

If you want to know the amps of your overall service, locate the box where electric service enters your house.  There should be an indication there. You may need to open the box door and take a look at the 'big breaker' there.

If you've got the ability, I think D&T's suggestion makes sense.  Personally, I've got a few solid 120v circuits on new 12 ga copper (which I wired myself!) that don't have a lot of load on them, so I plan to run a couple of miners on them, rather than going to 240v.

the main breaker in my box is 200 AMPs  :)

Then you are probably in good shape unless you live in some huge-assed place with electric heat, and charge electric cars, dry your clothes, run a half dozen hair dryers all the time, and have 89 inch tube TV.   ;D

Up to 44,000 watts!

You are more than ready to rock'n roll!

WOO HOO!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

:)

Correction. Wire gauge is based on current.  The wire requirements for 240V are exactly the same as 120V.


That is right and often wiring can be hard to trace down unless you test every outlet in the house.  Contractors can be cheap or lazy so there may be more on one branch circuit than what it first appears to be.  This is why if someone is looking to pull some serious power (2, 3, 4 KW of load) it really makes sense to run dedicated circuits.

The miners are on the miner circuit and nothing else is on them.


If you run out of capacity you can double it by using the same wiring and changing the outlet and breaker to create a 240V circuit.

In US 120V is
hot
neutral
ground

240V is
hot leg A
hot leg B
ground

So same # of conductors you are just using 2 hots instead of 1 hot & 1 neutral.  So you can upgrade without redoing the wire run by just changing the outlet and breaker (from single pole = 120V to double pole = 240V).

nice thread, thanks for the info guys.

You make a good point there perezoso!! 

In the garage where i was thinking of setting up the rigs i have a small freezer and a couple computers with a 5 monitor setup and that's it.. My washer and dryer , furnace, water heater are all not in the garage and i think they are on their own circuit. For example my panel shows the "dryer" and there is a 30 next to it so i think it has its own dedicated 30amp circuit.

 
I work from home in my garage so pausing for thought .. The panel is in the garage so its naturally a good place to set up but..

I think i greatly underestimated the power issues miners may face when scaling upwards. I need to rethink my setup and make considerations for noise and other environmental issues if im going to be in the same room with them all day. 


Originally i was thinking of using stack-able GPU frames and literally wheeling the miners to another room in my house when im working in the garage so now im rethinking how im going to set this up.. i would like to end up doing what DeathAndTaxes recommends and run the miners on their own circuit alone but the noise factor is my new hurdle i guess since i cant temporarily relocate them at will to just any socket in my home.

Edit : Removed Rant about Superbiiz screwing up my order! Ive located 10x 280x and im awaiting local delivery.

Oh man, thanks to some really nice people i just scored a load of 280x's locally!  
 Im off to grap box fans and parts but i had a question about the pdu!


Here is the one D&T linked too!
APC AP9571 1U Rackmount PDU 208V 24A



Here is a similiar model that cost $150 more and i noticed it is labeled 30A vs the 24A on the pdu D&T linked too..


Since im hoping to get a 30A dedicated circuit like D&T recommended, do i need the more expensive one labeled 30A?

like this one -->>  APC AP9571A Rack PDU/Basic/1U/30A    
http://www.amazon.com/APC-AP9571A-Basic-Surge-Protector/dp/B002UOIGVY



or can i get the cheaper 20A ones or the 24A ones?  like --> APC AP9571A 1U RACKMOUNT PDU 20A 208V

http://www.cwioutlet.com/p-4571-apc-ap9571a-1u-rackmount-pdu-20a-208v-surge-protector.aspx?gclid=CK_BldKdvbsCFYiVfgodoC4AYQ




Thanks in Advance

I've been using 3-4 of these for over a year with no problems... I purchased them used. They work great... I actually think it was from searching and seeing DT's recommendation that I ever bought one about a year ago. :)

It's definitely a good affordable PDU.

Hey CH!! Thanks for chiming in.. Appreciate it. Im gonna grab that APC! Im trying to find a local supplier so i dont have to wait even tho i still have to wait till the 24th for risers coming from china.


 
Zedicus

 

Technically, anything over 16 amps (on a 20 amp breaker) or 80% of the breaker's rating is considered an overloaded circuit.  You should try to keep under this threshold for your own safety.   

Great thread, thanks for all the info! I'm in the same boat, with some miners showing up in March (knock on wood). I was thinking to run 2 new 20amp, 110v circuits, but reading this it looks like one 30amp @ 240v would be better. I'll have 4 machines at 1050 watts each, but I may be able to overclock those by up to 20%, which would be 1260. The two 20amp circuits couldn't handle that, but I think the 30amp circuit could.

Although I'm wondering if I should have 2 circuits run at the same time, just in case I'd want to add anything later on. I'd guess a lot of the cost is in fishing the wires?

I had question related to the PDUs. I'd been planning on getting some power conditioner/voltage regulators like these (one per two miners): Tripp Lite LC2400 Line Conditioner 2400W AVR Surge 120V 20A (http://amzn.com/B0000514OG). I'd need to find a version for 240v, but I'm wondering if most people use these? My electric service is pretty good, but I figured I should have something like this in the line to protect the gear. Or is that not so necessary?

Thx!

Definitely .. DeathAndTaxes was sharing this with us a page back.  

I'm in Wichita, how about you?

Ohh... and Brownie isn't an idiot.........  He's just insane..............

You think your Brownie is worse?  Our governor is nicknamed Moonbeam.  Fitting for the Socialist Republic of Kalifornia.

My electricity is going up to $0.34 in 10 days  ::)

By the way, you're also forgetting about power factor. Crappy power supplies have a PF of .5 or so which means you're pulling a lot more volt-amps than if you had a better supply with a .8 or .9 PF rating. volt-amps are not quite the same thing as watts, and volt-amps are what generate heat in lines.

So.... Make sure you get good power supplies. The crappy BFL supplies have a PF of only .6, my Corsair is over .9. Oh and if you can, run your supplies on 240 volts, more efficient. Actually if you can get 3 phase and run 208 volts to your stuff.

C

Hey thanks for your input!! Currently im rocking 2x 1000 evga gold series power supplies as well as one corsair ax-1200..

So 4 280x's on the 1200 and then 3x a piece on the 2 evga power supplies.. Currently hunting for an electrician that fits my budget  ..

Not gonna brave the panel.. just gonna do the homerun.


http://www.corsair.com/professional-series-gold-ax1200-80-plus-gold-certified-fully-modular-power-supply.html
http://www.evga.com/Products/product.aspx?pn=120-g2-1000-xr

I currently have 20A on a 230V circuit (I live in the EU). I am currently in the process of getting three phase link - then I'll have 3x20A. Depending on the cable from the power company to my house, I may even be able to increase the power at a later date (or start using 400V power supplies to reduce the current).


Power factor is a compromise. PSUs with low PF use more current (so you can't run as many miners/etc), but active PFC can result in the power supply blowing up (I have repaired a couple of PSUs after they blew up because of active PFC). I guess passive PFC would be the way to go - better power factor, but no increased risk of blowing up.

Hey, i'm also in Wichita.  Just got a 3mh/s rig setup and thinking about another.  Reading through this thread to figure out where I'd put it in the basement.  Whenever my miners change pools I can see the lights flicker and the box fan cooling them gets faster for a sec :)

My main PC is also plugged into the same room, so I may separate those too.  Lot's to learn about electricity.

Side note: My chili and big miner (the 20gh jally) are both running on the Corsair power supply. Power factor is well over .91, which is an exceptional improvement of the .5 from the crap-o BFL supply and .6 from the crap-o 300 watt ATX supply.

So there you go.

So here's where I wound up. I have a contractor coming later this week to run a 50 amp circuit to a new sub panel in the basement. In that panel he'll put a 30A 240 and 20A 120.

I ordered this for the PDU: APC AP7941 Rack PDU (http://www.amazon.com/gp/product/B0007POM0C/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1). There was a seller with a used one for $50 (+15 shipping) on Amazon. I like the fact I can view the amps drawn and manage it through a web interface.

Then I'll have two of these that will go from the PDU to the machines: Tripp Lite ISOBAR4/220 Isobar Surge Protector Metal 230V 4 Outlet (http://www.amazon.com/gp/product/B00006HZ4N/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1). So each will have 2 machines on it (4 miners total).

This should let me overclock (if possible), from out of the box 1050W to +20% = 1260W / 240V = 5.25 amps * 4 machines, 21 amps out of 24A sustained rating on 30A circuit. That's only if I can get them all OCd, but at least the headroom's there.

This will leave me with a 20A circuit if I need a cooler or for expansion. Thanks for the help here, let me know if I'm blowing it somewhere!

Please also consider you may need to derate conductors based on length or ambient temperature.

Wiring heats up, and copper's conductivity actually DECREASES as temperature is increased, leading to more heating up, feedback loop = fire.

So, like other people on this thread have said, do not run more than 80% of rated power draw continuously.

If the circuit was built right, everything up to spec, it should be able to handle it, but, we all know that residential houses are all built by the lowest bidder, with the cheapest components available.

So, running more than 1100 W on a 15 A 120 V circuit, you're asking for trouble.

I now I ran into that problem also, which is why I sold off some mining gear. I simply did not have enough power to run it safely, and the extension cords from other circuits in the house were getting really annoying.

Man nice pdu!

i had i guy come out and when he opened the door to my panel it sparked everywhere and the power went out! Turns out i had a loose breaker which had defective coupler or what ever hold its into place...

After he opened it he said there is not room for any more breakers and i would need a sub panel or a new panel.


All in all i lost a 15 amp breaker and all that was on there got moved to a 20amp breaker that the garage door was running on. He said the Oven was on a 50amp and i looked at him and he started laughing! He said i should probably talk the other people in the house before i have him haul the oven away! LOL

He was just a contractor that was in the neighborhood doing me a solid so now at least i know i need a new panel or a sub panel.  :(

PDU and outlets just came.. Got the 10guage line too..  Just a bit brick walled with this panel issue. I gotta find out the costs of swapping to larger panels or adding a sub. Anyone know?

By the way i found i have 100-125 amp service by calling the power company!

 
https://i.imgur.com/ORTJqQE.jpg
 

Panel change out here with a new 200amp service runs 2500-2900. Could be more if your installation is a pain in the ass.  Depending on the brand and model of panel you have you could use some tandem breakers to free up some space.  

Do you have an electric hot water heater? Is it in the basement?  Replace the breaker feeding your water heater with a 60amp to feed a sub panel, then feed your water heater from the sub panel.

You could do the same with any of the circuits in your house, the water heater is usually the handiest 240v to access in the basement.

Holy crap! $3k! I wasnt expecting that..
I hope just adding a sub panel is cheaper.

Not sure about my water heater.. ill look in the morning.

Yep, It may be different where you live, but the electricians here were smart.  Electrical work is the only protected construction trade.  Anyone can decide one day they want to install gas lines and they are in business, but not electrical.  It ruins competition.  In all fact, that 2900 install has maybe 800 in materials and 10 hours of labor. It is bullshit, but you don't have a choice.

I was hoping to find and electrician friend of mine but he comes up missing 3-5 months at a time because he has a serious gambling problem. He has a thing for Pai Gow.. I may call his wife to see if she can hunt him down for me. Last time i got him in trouble so im being patient..

Thanks for the price guide btw! Good to know what im dealing with!

Maybe home builders should get on it.  We have dining rooms, powder rooms, baby rooms, reading rooms....

I think it is time they put in "computer data center rooms", with 100A panels, independent AC, home automation panels etc.

Lol, Houses are build with the cheapest material by the lowest bidder.  That isn't likely.

Thank you all for the info. Very valuable for noobs like myself.

Just to make sure I understand it correctly; I run dedicated 30 amp 240v w/10 awg line with l6 30p outlet. I buy pdu rated 30 amp with l6 30p  (24 de rated ) like the APC 9571A and I am good for 5k watt right?

My circuit breaker has  2 spaces empty next to each other but I am not sure what is the total power coming in to the house.

Also, standard ATX psu in the US is rated to use 240v ? I know that all my three rigs are hooked to 120v outlets right now.

5.76kw, and two spaces next to each other usually means you can get 240v.  Some GE panels have 2 spaces before it changes legs.  If you install the breaker and it shows ~240v between poles you are good to go, If it shows 0v then rearrange the breakers to move it down one space.

The power supply may have a switch on the back to switch it from 120v to 240v. If it doesn't have a switch look at the label and check that the voltage range goes to 240v and hook it up.

Thanks for the quick reply. I appreciate it repairguy :)

A lot of good advice here  ;D

BUT,I didn't see any mention of AWG amp limits mentioned:

Same amp limits @ 120 volt or 220 volt.

14 AWG=15 amps or 120 volt 1800=watts-20%=1440 watts useable/220 volt=3300 watts- 20%=2640 watts useable

12 AWG=25 amps or 120 volts 3000=watts-20%=2400 watts useable/220 volt=5500 watts-20%=4400 watts useable

10 AWG=40 amps or 120 volt  4800=watts-20%=3840 watts useable/220 volts=8800 watts-20%=7040 watts useable

8 AWG=60 amps or 120 volt  7200=watts-20%=5760 watts useable/220 volts=13200 watts-20%=10560 watts useable

Get some 6 inch pieces of different gauge wire from home depot & pull the cover off the breaker panel & just hold a piece of sample wire near the wire going into the breaker until you have a match.

DO NOT TOUCH ANY WIRES OR OTHER PARTS,YOU MAY GET SHOCKED.Just a CYA  8)

THESE ARE ESTIMATES,CHECK WITH AN ELECTRICIAN FIRST!!!!!

The wire ampacity was mentioned, however the wire comparison was not because it isn't relevant to the topic. Also your information is incorrect so your not really helping anyone

Well,then post the correct info  ::)

Show me where I am so far off.

Gladly,

2011 NEC Table 310.15(b)(16)
60 degree column
14awg  15amp
12awg  20amp
10awg  30amp
 8awg  40amp
 6awg  55amp
 4awg  70amp
 3awg  85amp
 2awg  95amp
 1awg 110amp


I am not going to calculate the watts, For any one interested, take amperage x voltage x 0.8 to get your total watts for a constant load.

Thank you,but I'm an A/C installer & have been for over 8 years,an electrician for 4 years before that.

As an example,8 AWG is very common here in florida for 5 ton/10kw air handlers.Normal draw is 48-52 amps at start up.Never had an issue with well over 1000 installs  ;)

It's good that it under rates the amperage though,better safe than sorry   ;)

Really? You have a 5ton ac that starts at 52 amps.  The 5 tonners I install pull 150+ at startup, However the rla is 29.2 amps x 1.25 is 36.5 amps and 8 gauge wire is appropriate for that.

They aren't underrated, that is code. A 12 gauge wire will carry 100+ amps, It will just get really hot. The code is calculated based on safe temperature for the wire and the insulation around it.(I thought you were an electrician? You should know this!)  Also circuits are not sized on startup loads, A single phase psc motor like a refrigeration compressor will draw its lra when it starts, but that is only for a few seconds.  The circuit is designed on rla.

LostDuchman, Do you have any pics of your mining farm? 

Also, What's the meaning behind the name?  Any nod to mythical "Lost Duchman Mine" in California, or Arizona, or Colorado???  (Where eve they claim it is now...)  Do you prospect with the GPAA?

Thanks for entertaining me!

Woodser

Do these pdu's need some kind of adapter on the inputs or what?

https://i.imgur.com/lxfBud1.jpg
 

I just noticed the one i have (pictured) wont allow me to plug in my rig into those input slots. My rig uses standard atx- power supply.   The end that plugs in into the wall or power has a round ground. Like this ...

http://www.arcocomputers.com/images/black%20power%20cord.jpg


Do i need special cables /adapter now to go from my power supply to connect to the inputs on the pdu?

http://www.ebay.com/itm/AC-Power-Cord-C13-to-C14-14-AWG-2-Grey-Lifetime-Warranty-/370989253263?pt=US_Power_Cables_Connectors&hash=item5660aec28f

^^ Hey Repair guy thanks!! But dont be a dickhead! You were snarking at Unacceptable for trying to help and he had to call you out on it for you to even retort with an answer  ..

If you are a prick by nature and im asking something of you that you just cant manage, i understand..

In life you always pay for everything with time, money or inconvenience. In this case i paid with cash for an electrician and parts and in btc i will be paying to whatever Death&Taxes bitcoin address is.

Furthermore i may just pony up some btc to a couple other random people in this thread like Pentax, LostDutchman, Coinhoarder, Dalkore, Unacceptable and lightfoot since they gladly jumped to help a newbie miner from making mistakes that may lead to his home burning down. I work like 10 hours a day so i may miss some stuff when im speed reading just trying to get stuff to work and they where helpful and appreciated.

 Now if you have another snarky reply then just shut the fuck up and and get the fuck out my thread.  

But if you want to be helpful in a thread that may help many other people, now and in the future then carry on. Your knowledge and experience is welcome.


Everybody else, thank you very much your help was very much appreciated! Mission is accomplished!! I got a dedicated 30a breaker. I got the 10 gauge branch line and the nema l6-30r locking outlet & PDU so im good to go!  If i scale up any further ill just duplicate the setup.



For anyone starting this thread backwards you want this below!

********************************************************
THE DEATH&TAXES PROTOCOL :
 30A breaker, 10AWG branch line, and a NEMA L6-30R outlet (240V, 30A, locking).  Cheap used datacenter PDU with a NEMA L6-30P plug.  "Good for a solid 5.76KW."

Sorry, I was being a large dick, I apologize. By the double f bomb drop I hope your not still upset with me.  I really did intend to help, otherwise I wouldn't have posted. I am having difficulty with something totally different and have been screwing with it for idk how many hours and it was pissing me off and vented a little here, With the spoon fed comment, Sorry.

However, Nothing irritates me more than people who claim to know what they are doing and clearly have no idea, I corrected him, referenced the code and he still argued. Wtf? 

I really do want to be helpful, I enjoy this hobby and want to encourage others the same.

^^ Aw man.. now i feel bad.  :o  Apology accepted! I had one of those days last week so i know what ya mean!

Thanks for your input in this thread man!! Good luck on what you were working on..

That whole deal with unnaceptable irritated me because he provided wrong information and I corrected him and referenced the code, then he still argued with me about something he clearly had no knowledge of.  I guess I kind of took it as insulting.  Again sorry.

Good luck to you with your rig building. The cord you are looking for is a c13 to c14, and if you look around be sure to use one that is at least 14awg.

^^ Good deal! Thanks again man! I will source it tomorrow hopefully locally.. if not i will snag a couple from the one you linked to.

I had the same question on adapters and got some of these http://amzn.com/B004OC579E (http://amzn.com/B004OC579E) and these http://amzn.com/B00066HQ50 (http://amzn.com/B00066HQ50). They both seem to do the trick, though I don't have my outlet installed yet, so haven't fired everything up. They're pretty inexpensive, especially if you have Prime.

Btw, to your original post, I had an electrician install a 50A subpanel to my basement (rather than running 2 circuits). I'll run a 30A 240 and 20A 110 from it. It cost $550 -- they said it generally is about $10 * #Amps, more or less. That's in Colorado, fwiw, maybe give a general ballpark at least. It was a pretty short run from my existing panel (maybe 25'?) and another friend helped get it prepped with a channel through to the basement.

My main gear will run on the 240 and I'll have that 20A if I need to add a/c or for future machines. Thanks also to all in this thread for the advice!

While that will work they make cords which have the correct connectors on each end.  As pointed out above you just need a C13 to C14 cord.  It is pretty common in datacenters.   Almost all electronics (like your ATX PSU) have C14 inlet, and PDU have C13 outlet.  So a single cord is used for everything.  Servers, switches, routers, firewalls, etc.

For amazon:
http://www.amazon.com/Tripp-Lite-P004-004-18AWG-Connectors/dp/B003MG9F78/ref=sr_1_2?s=electronics&ie=UTF8&qid=1390094044&sr=1-2&keywords=C13+to+C14

This is just an example I typed "C13 to C14" there may be (and likely is a cheaper, better version) but the cable one needs to go from PDU to PSU without any adapters is a C13 to C14 cable.

DeathAndTaxes!!! Nice link .. cheap too!!

 Thanks for your contribution to this thread! Where is your btc tip jar..!! I wanna by ya beer!
Ill hunt you down from your site if i dont hear from you! Thanks again.






 



^^ hey Tom thanks for the feedback! I just tried to source some locally with no luck.. im gonna try frys tomorrow before i just grab something online..

http://www.amazon.com/dp/B00066HQ50/ref=cm_sw_su_dp

That looks great! Cheap too.. The only thing i can think of is the one that repairguy posted was 6' i think!

I can really use the distance. In fact one of my miners is about 20 feet from where the pdu is and i was thinking about daisy chaining a couple of these cords to get to it so the longer the better.

I also wanted to take his advice and get an 14AWG one at least and the one listed on amazon does not list wire gauge.

In terms of costs .. I paid close to $140 to have all the breakers on the right side of my panel swapped out since they had bad contacts and they were chared and black at the contacts and they were old discontinued breakers too. Swapped one of the ones on the left too.. That price included a new 30a dedicated breaker and doing the home-run from the panel and installing a new outlet.

So glad i didn't need a sub panel or a completely new panel. That would have ballooned the costs.



 

Good to know this is being talked about. The thread should be called "How not to burn your house down". Love it keep up the good work. Now only if someone translated everything in this thread so that a 15 year old boy could understand then I'm goodhhahaha

I don't need a tip (I got a coin or two in the ole wallet.dat), glad to help for free.  My miner days are likely coming to a close so I will need to mine vicariously.

<shamless plug mode>
If you absolutely feel the need to help ...  consider https://bitSimple.com next time you need to sell some coins to pay that electric bill. :)
</shameless plug mode>

D&T!! You are a gem man! Thanks!! I will definitely check out https://bitsimple.com/

Electricity bill is due in about a week and a half.. :)

We're looking at setting up 2-3 server racks worth of GPU rigs, and powering them all off 220. Each rack will be using ~8kW (possible more), which will be 35+A if we use 220.

So lets say we use 9kW per rack. We'll just do two of your setups? 6x 30A 220 breakers. 10ga wire run ~100ft to our room, and terminate to 6x L6-30R outlets. 2x Compaq 24A PDUs with L6-30R plugs per rack. Then each PDU will power 3 rigs, with 3 of these (http://www.ebay.com/itm/6ft-16AWG-Power-Extension-Cord-Cable-w-3-Conductor-PC-Mon-C13-C14-Black-/370977718810), and 3 of these (http://www.provantage.com/tripp-lite-p047-006~7TRP90LW.htm). Each rig will use an ATX PSU, and a custom server PSU.

The problem I see is that the breaker is 30A, but is being limited by the PDU to 24A, which if run at 80% load is only ~20A. Is it a better idea to install a single 50A 220 breaker per rack, run 8awg wire to 2x L6-30P, and then run both of the 24A PDUs per rack to those? The actual draw through the PDUs wouldn't change, would still be at ~20A each, but now you've got 8awg wire carrying 40A to a 50A breaker, rather than 2x 10awg carrying 20A each to 2x 30A breakers. Does this make sense?

Although I suppose if we did that, we're really limited to 40A per rack. If we went with the 2x 30A, we could upgrade the 2x 24A PDUs with 4x 16A PDUs. As long as each of the 16A PDUs were kept below 13A, the draw per breaker would be ~25A, and the total draw per rack could be increased to 52A, or 11kW.

So if we're only pulling 8-9kW per rack, we could get away with a 50A breaker and 2x 24A PDUs? But if we wanted to pull more, splitting it up between multiple breakers would give us more headroom?

I also realize that we're going to have to run another breaker for our AC equipment, but that's a topic for another day. And I'm not really an electrician, I'm just trying to figure this all out. Any suggestions welcome!

Hey crazyates! Welcome to the thread!  Sounds like you got a handful there ..

Hopefully one of the resident gurus can take a stab at your questions.. good luck!



Hopefully
If you are 15 then talk to the home owner!! This is serious ****!  Do not open your panel or attempt yourself!

Don't bother looking at brand stores like Office Depot ,Home Depot , menards, or best buy ! The don't have it. I went with new egg 10 feet 14 Awg for $13.99

http://www.newegg.com/Product/Product.aspx?Item=N82E16812120828

I was laughing at myself when the electrician in my house asking me to plug something to test the Newley installed breaker! Of course nothing fit the pdu cause it's that c 13 needs c14 and I am trying to plug my regular standard ATX to the pdu  ;D

Edit: you may already know some of this the post became more of a general guide as I kept type.

So a couple things. The first is that in the use despite the common usage of "110" or "220" nominal voltage is 120 & 240.  You should however stick a multimeter into an outlet to find out.  You can test a 120V outlet, the 240V is going to be double that.  Unless you are at the far end of distribution the measured voltage at the outlet is probably closer to 120/240 then 110 /120.  Still you should adjust the power capacity numbers based off your actual voltage.

The second is that the 24A per PDU already includes the derate.  The circuit (30A breaker, 10AWG wiring, NEMA L6-30R outlet) is rated for 30A peak load.  Continual load is derated to 80% of that so 30A * 0.8 = 24A.  A code compliant circuit using a NEMA L6-30R receptacle (proper name for "outlet", outlets are actually on the PDU) is good for 24A continual or 30A peak.  That is why the PDU lists 24A, you don't have to further derate that.  Putting it together with 240V means each PDU is good for 5.76KW of power per pdu.

Third.  I am sure you have double checked but most PDU don't use C19 connectors.  I assume your server PDU is "beefy" and pulls more than 12A?  Just don't want someone ready briefly to be confused.  Almost all PSU have a C13 connector.  PDU have a C14 connector so the cable most people will need is one C13 to C14 cable per device. 

Are there other options? 
Well there are but I think you find any other option is either more expensive or not up to code. 240V, 30A circuit just comes down to the most economical choice.  The used PDUs are dirt cheap, the outlets are nothing "exotic" (even home depot probably carries a NEMA L6-30R is look hard enough) and while 10AWG isn't "fun" to work with it is still a lot easier to manage then the larger cables.  For example the standard connector for a 50A circuit is a NEMA L6-50R which doesn't exist except on paper, as safer pin and sleeve solutions are used. One common alternative is the California standard (become widely used in movie industry) http://www.stayonline.com/detail.aspx?id=6272 

Yeah that is the plug only.  $70.  A matching outlet is another $50 to $70.  To make a custom cable which converts a 50A connector into 2x NEMAL L6-30 plus the 50A outlet is probably going to run you $250+. :)  So I am not saying "the 30A route" is the only possible way to deliver power, I am just saying trust me I did the research and cost per KW you aren't going to find a cheaper, code compliant solution then using 240V 30A circuits and 30A (derated to 24A) used PDUs. 

So if you need <5.76KW of power.  Install one 30A breaker, make one 10AWG run, install one NEM L6-30R outlet, and get one matching PDU*.
So if you need <11.52KW of power.  Install two 30A breakers, make two 10AWG run, install two NEM L6-30R outlets, and get two matching PDUs*.
So if you need <17.28KW of power.  Install three 30A breakers, make three 10AWG run, install three NEM L6-30R outlets, and get three matching PDUs*.
So if you need <23.04KW of power.  Install four 30A breakers, make four 10AWG run, install four NEM L6-30R outlets, and get four matching PDUs*.
...

* I recommend using the APC AP9571.  There is nothing magical about it but APC made millions of them so there are tons of used ones on ebay for dirt cheap.
http://www.upsforless.com/ProductImages/apc-2/ap9571.jpg

An ebay listing may say 208V but it works fine at 240V as well (datacenters are usually 208V which is why it lists that).
30A, 24A derated (5.76KW usable)
NEMA L6-30P plug to match your economical NAM L6-30R recptacle.
Has twelve C14 outlets.
Just get some C14 to C13 cables from amazon or monoprice (<$5 ea) to connect from the PDU to each PSU.

If the distance from your breaker panel to where your rigs (and NEMA L6-30R receptacles) is long you may want to consider a subpanel.  How this would work is that in your main panel one or more high current breakers is used and a single run with large gauge wire is run to a sub panel located near the rigs.   The sub panel then has say 6 30A breakers and short 10 AWG runs to NEMA L6-30R receptacles.

If you go another route just remember you can pull the full rated current of the PDU (as it has already been derated).  However the circuit (receptacle, wiring, and breaker) has to be designed such that the continual load is only 80% of the circuit peak capacity. Some PDU labels will list both capacities (30A, 24A derated).  This is why you will find PDUs generally are 12, 16, 24, or 40 Amps.

12A PDU is 80% of a 15A circuit (15A outlet, wiring, and breaker)
16A PDU is 80% of a 20A circuit (20A outlet, wiring, and breaker)
24A PDU is 80% of a 30A circuit (30A outlet, wiring, and breaker)  <- The sweet spot in terms of $/KW installed
40A PDU is 80% of a 50A circuit (50A outlet, wiring, and breaker)

Another piece of advice is to start small (i.e. start with enough gear to fill one 5.76KW "unit").  Speaking from personal experience when you start getting into the tens of KW of power range everything becomes more of a challenge especially cooling.  It is much easier to design a single efficient layout (say half a rack) and then scale out, rather than buying gear needing 30KW+ and then realizing the engineering, power, and cooling challenges are no joke.

That is a lot of info, and exactly what I was looking for! Thank you SO much!

I hadn't realized that the PDUs were already derated. This makes much more sense when planning everything out. We'll probably have to run a subpanel to our room like you suggested, and then we'll add as many 30A breakers as we need. This gives us the option to grow, and now I feel a whole lot more comfortable, knowing exactly what we need.

Yeah, all of our ATX PSUs will use a standard C14-C13 power cable, but we have some PSUs that will use a C14-C19 cable. I briefly checked out that model PDU, and looks like it will do exactly what we want.

We've already started with a half a rack, and are planning on moving that half rack to a new location (and then filling in another 2 racks), but we haven't decided which. Either one can have power brought to it, but cooling is another issue, and more than likely for another thread. One thought was a wide, short room which has 5 windows, and we could put a 24000btu window AC in each one. Another option was a smaller room with only 2 windows, and maybe an exhaust fan near the ceiling. Both rooms have tall ceilings, and we're in the NE, so it's pretty cold this time of year. As a temporary solution, we could just have the ACs on the fan setting, blowing in the 20F air! Once summer hits it'll be different, but we can get situated by then.

But back on topic. I've got the info I need for the power, so I thank you again!

1x 24k btu should be close to enough for 3 9kw racks.  2x 18k btu would be plenty. Assuming your not cooling a large space along with the racks. However keep in mind window air units are not ideal for this situation.

Do not use a c14 to c19 adapter.  The c19 cable is rated for more power than the c14 can safely carry. Use a different pdu with a c19 connector to run your "beefier" stuff.

They make higher ampacity multiphase pdus that can handle a lot more load.  It is kind of a balance, the larger pdus save on wiring, but the availability of the pdu can be more challenging or expensive.

Here is a good one for your c19 units

http://www.ebay.com/itm/Dell-4-Port-200-240V-PDU-L6-30-AP6031-5T439-/191035120115?pt=US_Power_Distribution_Units&hash=item2c7a9499f3

Here is the cord

http://www.ebay.com/itm/DELL-8-FT-C19-TO-C20-POWER-EXTENSION-CORD-16A-230V-2-5M-1000W-2X976-CN-02X976-/390563779661?pt=LH_DefaultDomain_0&hash=item5aef6a544d

C14 is still rated for 10A, and we're not pulling 2kW through any single port. In fact, most of our individual power cables (after the PDU) will only be pulling 3-5A, so I think it'll be fine.

I picked up a CW-8H2-L630 to try. 208-240V 24A 8xC13 Switched PDU. It was cheap, with plenty of features. I can't wait to try it out and see how well it works.

So then you must be using 120-240v power supplies.  Then you are probably ok.  They use the heavy duty connector for 120v use, but it isn't necessary for 240v.  Sorry didn't know which power supply you were using.

Agreed!  Thank you DeathAndTaxes.

I was wondering something really quick and also goes with the note of starting smaller.  If I get a house that comes with 200amp service, lets say I want to setup a subpanel and run 3 30amp breakers, would turning that subpanel box into a 240v be a complicated or rather simple task?  I will hire a pro to do it of course, I just want to get an idea if I could easily run 3 30amp 240v breakers for a bit right off the bat without many complications before eventually upgrading to 400amp service, etc.

If you install a sub panel, It is going to be 240v.  I have never seen an electrician install 120v sub panel.  you are going to need to run 100amp sub panel. Not a difficult task, however some panels are not made to install a 100amp breaker in them.  If that is the case you will need to replace your primary panel or install a 200amp "sub"panel and feed it directly off the meter (if your meter has overcurrent protection, otherwise you are looking at a new meter can), although it technically wouldn't be a sub panel then.

When you upgrade to 400amp are you going to feed more power to your sub panel or add an additional one?  A 200amp service should be able to run 4 or 5 30amp twist locks and the rest of a house pretty easily. (unless you have one of those electric instant hot water heaters).

What is your long term plan.  I would hate to see you waste alot of money for something temporary.

Thanks man I very much appreciate your help.  When I move I am just going to get the 400amp right off the bat.  I was wondering one more thing though.  I am staying in a townhouse right now and the owner said I can have a few changes made as long as I have it put back before I leave.  So for now I need more juice.  I uploaded pics of my box.  Are you able to tell how many amps it is?  And also, are those double breakers 240v? if not would I be able to have one of them switched out one of them for a 240v?  The baseboard heater I never use and it has dual 20s.  What do you think?

http://i693.photobucket.com/albums/vv296/WaveRider69/th_IMG_3298.jpg (http://s693.photobucket.com/user/WaveRider69/media/IMG_3298.jpg.html)http://i693.photobucket.com/albums/vv296/WaveRider69/th_IMG_3306.jpg (http://s693.photobucket.com/user/WaveRider69/media/IMG_3306.jpg.html)http://i693.photobucket.com/albums/vv296/WaveRider69/th_IMG_3299.jpg (http://s693.photobucket.com/user/WaveRider69/media/IMG_3299.jpg.html)

First off, thanks everyone for this thread.

I live in an apartment so I cannot make any major modifications to my panels/wiring. I was running into issues with my breakers on the normal 120v outlets. However, I have an air conditioner that runs off of a 220/240v plug. I believe that it is a NEMA 6-15. A lot of the server PDU's I've found use a 6-30 inlet, which I am assuming is not compatible. I do not remember seeing a 30 amp breaker in the box, but I can double check that.

Are there any sort of PDU/power strips that I can safely plug into a 6-15 outlet? I can't seem to find any. I'd like to run two PSU's (approximately 2 kw of hardware) through the air conditioner outlet, if possible. I would also like to keep the air conditioner plugged in, even if it is not running, but this is not as important. Would a simple 3-4 outlet strip that plugs into a 6-15 outlet suffice?

Is this something I can safely do?

Yes the Double breakers are 240v.  Do you have a clothes dryer or electric stove in your apartment? Unless you want to set the equipment right below the panel  I cannot tell you exactly how many amps you have serving your panel.  The best I can tell you is you have at the most 100amps.

Yeah, there is washer/dryer and all the appliances, everything is electric and we are able to run everything at once, washer/dryer/stove/dishwasher/water heater/all rooms/etc.  The breakers in the box add up to over 250amps.  There is a double 40, two double 30s, a double 20, a double 15, and then then standard lot of random 15's and 20's

Disclaimer: I am not an electrician. I am a moron.

That said, the problem normally isn't plugging a higher rated power distribution device into a lower rated socket, it's plugging a lower rated power distribution device into a higher rated socket.

The reason is if you pull too much power through a higher rated dist device, the lower rated breaker in the panel will open. Boo hoo. However if you have a 30 amp socket and you plug a 15 amp electrical cord into it, then a short in the device will not trip the breaker before the cord heats up and hilarity ensues.

Does that help?

C

So what you're saying is that if the plugs are compatible, it won't matter? The breaker will go long before any issues in the the pdu?

http://internationalconfig.com/icc6.asp?item=5642-I

So if I remove the AC plug from the wall and plug this in, I should be fine?

The total amperage of your breakers doesn't mean anything.  They commonly go 2-3x your total service, because you're not going to use 100% of it all at once.  You can just call the power company and ask.  If you have a detached home you can look at the main breaker.

You could mount a pair of those in a utility box with a short plug lead on it and not have to touch the wall plug.  Just make sure you use 14 AWG wire or bigger for a 15 amp circuit.

I just had 2 of these 30 amp 240 volt lines with 10 gauge wiring installed and running the APC 9571 PDU on each of them. This past weekend when the temperatures got in the 80s the circuit breakers got really warm (I could still hold my hand to them, but barely) to the touch and the plugs at the wall were each very warm. Should I be worried about this? I can't imagine what will happen when the temps get up to 100 degrees. Now that it's cooled off again everything is nice and cool. I'm running 19 amps on each one.

19amps? as in you measured it?

Also, What does the outdoor temp matter? Do you not air condition your house?

Yes I measured it with one of those things with a claw that goes over the wire and tells you the amperage. The fuse box is outside and I set the AC to 85. How does any of this help answer my question?

Is the claw rated for 240 volts? Usually they look for the inductance based on a single hot (120), not two hots (240)

Just a thought.

C

I have never seen a clamp meter that is rated for less than 600v, and that rating is for arc hazard and has nothing to do with accuracy.  amperage is amperage doesn't matter the voltage.

Wire and breakers will get warm when running large current(proportionate to their diameter) even within the range that is considered safe or acceptable.

If wire is running in an unconditioned space, and is subject to high ambient temperature, then it should be derated in addition to the derating for a constant load.

The wire in normal conditions is rated for 30amp, derated 20 percent for constant load is 24amp if your setup is properly installed, not exposed to excessive ambient temperature and your reading of 19amps is accurate, then it would be my opinion that it is probably ok, your idea of warm could be different than mine.

The best advice that I can give without actually looking at it myself would be that if it concerns you, call your electrician back over on a warm day.  A service call is a very inexpensive piece of mind.

Grab an IR thermometer and get an actual reading of the temp.

The trick though is these devices measure the differential in current as measured by a magnetic field around the wires. Stronger the field, more amps. However that assumes a hot and ground, I think you have two hots.

Whatever, good luck.

Two hots makes no difference in the current (and thus magnetic field  and thus reported current).  Two hots increases the voltage.  The two 120V hots are out of phase so there is 240V potential between hots and 120V between either hot and the ground.