Residential Limit 15amp or 20amp?

[zedicus]

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

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

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

[DontMineMe]

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  

[DeathAndTaxes]

********************************************************
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."

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, and 3 of these. 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!

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.


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.

[crazyates]

The second is that the 24A per PDU already includes the derate.  ...  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. 

240V, 30A circuit just comes down to the most economical choice.  The used PDUs are dirt cheap, the outlets are nothing "exotic".

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. 

* I recommend using the APC AP9571.

You may want to consider a subpanel.

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!

[repairguy]

The second is that the 24A per PDU already includes the derate.  ...  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.  

240V, 30A circuit just comes down to the most economical choice.  The used PDUs are dirt cheap, the outlets are nothing "exotic".

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.  

* I recommend using the APC AP9571.

You may want to consider a subpanel.

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.

[repairguy]

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

[crazyates]

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.

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.

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

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.

[repairguy]

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.

[Gazza1]

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

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.

[repairguy]

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

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.

[Gazza1]

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

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?

[Delarock]

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?

[repairguy]

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?

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.

[Gazza1]

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?

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

[lightfoot]

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?

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

[Delarock]

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?

[cp1]

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

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.

[fractalbc]

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?

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.

[agilityvision]

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.

[repairguy]

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?