For 4 mining rigs (GPUs) plug on 120V/20A outlet which PDU to use for safety?

[Didz]

Hi Bitcointalk,

I recently changed my electrical panel from 150 AMP to 200 AMP and then my electrician installed 4 outlets of 120V/20A each in my garage.

I understand that for one outlet of 120V/20A, the maximum Watts is 120 X 20 = 2400 Watts and with the 80% safety for power surge I can safely use 1920 Watts (2400 X 80%) or my electrician told me you're good with 2000 Watts per outlet.

The problem I had is that I was looking online to buy a power meter to monitor the total number of Watts I pull from one outlet (to stay at or under 2000 Watts for safety). The power meter I have (P3 Kill-A-Watt) has an amperage capacity of 15 Amps so I cannot use that device because my outlet is 20 Amps.

I was looking for a power meter that I can plug directly in the outlet for 20 Amps and apparently it doesn't exist. I called my electrician and he had issue to understand my question. He was telling me: "look at the device you want to plug for instance a fridge it's written on the sticker the Max Watts". I tried to explain that a mining rig has many electrical components and I will try different GPUs with different power consumption etc. but he was confused.

So I just bought on Amazon a Power distribution unit with a display showing amperage, voltage, KW, IP Address, etc. It is this model: CyberPower PDU41002 Switched PDU, 120V/20A, 8 Outlets
Its power plug is L5-20P so I had to buy a power adapter cable (L5-20P to NEMA-L5-20R 125-Volt 20-Amp) because my outlet installed in my garage are NEMA 5-20.

I am writing all this because I am a newbie with electricity and installing many GPUs mining rigs and I would like to know if my thought processes is correct? Also the PDU is CAD$ 426 which is not cheap. Will I have to buy these kind of PDU for every rack/outlet (I want to fill 3 or 4 mining rigs per rack and per outlet) I want to manage?

Thank you

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[philipma1957]

Hi Bitcointalk,

I recently changed my electrical panel from 150 AMP to 200 AMP and then my electrician installed 4 outlets of 120V/20A each in my garage.

I understand that for one outlet of 120V/20A, the maximum Watts is 120 X 20 = 2400 Watts and with the 80% safety for power surge I can safely use 1920 Watts (2400 X 80%) or my electrician told me you're good with 2000 Watts per outlet.

The problem I had is that I was looking online to buy a power meter to monitor the total number of Watts I pull from one outlet (to stay at or under 2000 Watts for safety). The power meter I have (P3 Kill-A-Watt) has an amperage capacity of 15 Amps so I cannot use that device because my outlet is 20 Amps.

I was looking for a power meter that I can plug directly in the outlet for 20 Amps and apparently it doesn't exist. I called my electrician and he had issue to understand my question. He was telling me: "look at the device you want to plug for instance a fridge it's written on the sticker the Max Watts". I tried to explain that a mining rig has many electrical components and I will try different GPUs with different power consumption etc. but he was confused.

So I just bought on Amazon a Power distribution unit with a display showing amperage, voltage, KW, IP Address, etc. It is this model: CyberPower PDU41002 Switched PDU, 120V/20A, 8 Outlets
Its power plug is L5-20P so I had to buy a power adapter cable (L5-20P to NEMA-L5-20R 125-Volt 20-Amp) because my outlet installed in my garage are NEMA 5-20.

I am writing all this because I am a newbie with electricity and installing many GPUs mining rigs and I would like to know if my thought processes is correct? Also the PDU is CAD$ 426 which is not cheap. Will I have to buy these kind of PDU for every rack/outlet (I want to fill 3 or 4 mining rigs per rack and per outlet) I want to manage?

Thank you

Well before you did anything at all you should have asked us what to do
.
you really should have went with 220/240 not 120

I can not begin to tell you how much you fucked up by having 120 v outlets installed.

1)So first question I have to attempt to fix the fuck up is to ask where is the  200 amp box.
2)second question I have to attempt to fix the fuck up is do you have 4 separate circuits each one for 20 amps.
3)third question I have to attempt the fuck up if there are 4 circuits going to 4 outlets how many rigs do you have.
4)fourth  question is since he switched out a 150 amp box for a 200 amp box do you have empty slots in the new box.
5) fifth question is how many rigs using how much power do you have right now.

you really should have went with 220/240 not 120


at least you are able to say you do not understand what to ask for.

The fix could be cheap if you have dedicated outlets to dedicated circuits.

[Looper_U]

Why 120V? That's no good my friend, you should have built a 240V instead, so you will have to be looking into equipments you can run on that 120V, that's a bad idea, almost all electricity appliances can work on 240V but not all can work on 120V, some will even cause problem for you

[Didz]

Thank you philipma1957 for your answer, really helpful! Let me answer your questions:

Question 1) So first question I have to attempt to fix the fuck up is to ask where is the  200 amp box?


The 200 amp box is installed in the washing room in my basement next to the garage where I set up my racks for mining.

Question 2) second question I have to attempt to fix the fuck up is do you have 4 separate circuits each one for 20 amps.

Yes my electrician installed on my panel 4 separate circuits each one for 20 amps.

Question 3) third question I have to attempt the fuck up if there are 4 circuits going to 4 outlets how many rigs do you have.

Yes so my thought processes is that for each circuit of 120 V and 20 A, the maximum wattage I can safely pull is 1920 watts (after applying 80% rule) or 16 Amp and I presently have 2 mining rigs pulling 1260 Watts (I see it thanks to the PDU with the meter integrated). I am planning to add a third mining rigs (6 GPUs GTX 1660 Super) which will be pretty close to 1920 Watts then I repeat that for each circuit/outlet.

Question 4) fourth question is since he switched out a 150 amp box for a 200 amp box do you have empty slots in the new box.

Yes in my new electrical panel I now have 13 empty/available slots for new breakers.

5) fifth question is how many rigs using how much power do you have right now.

Now I have 2 mining rigs using in average 600 Watts each and soon I will have 2 more mining rigs same type (6 GPUs, total: 600 Watts each rig).

I really explained to the electrician that I wanted to mine cryptocurrency and that I would like to have 10 kW in my garage available for that and this is what he sold me. Yea I am a newbie  

Thanks for your answer.
 

[Didz]

Why 120V? That's no good my friend, you should have built a 240V instead, so you will have to be looking into equipments you can run on that 120V, that's a bad idea, almost all electricity appliances can work on 240V but not all can work on 120V, some will even cause problem for you

Looper_U do you think I will run into problems if I plug 3 mining rigs (600 Watts each) on a 120V outlet?
I will never plug ASIC on a 120V outlet but for GPUs I thought it's starting small.

Thanks

[bretthexum]

I did a similar setup and couldn't run 220 for variety of reasons.

I got a nice 20 amp Tripp Lite PDU from Amazon that shows amps.  80% would be 16 amps.  I never go over that.

I ran the electric a while back before mining, so it's what I got.  Eventually I'd like to get 220 setup somewhere but kind of out of space on the box.

[Didz]

I did a similar setup and couldn't run 220 for variety of reasons.

I got a nice 20 amp Tripp Lite PDU from Amazon that shows amps.  80% would be 16 amps.  I never go over that.

I ran the electric a while back before mining, so it's what I got.  Eventually I'd like to get 220 setup somewhere but kind of out of space on the box.

bretthexum, when you wrote "I did a similar setup and couldn't run 220 for variety of reasons.", are you referring to the new NVIDIA CMP 220HX?

Thanks

[bretthexum]

I did a similar setup and couldn't run 220 for variety of reasons.

I got a nice 20 amp Tripp Lite PDU from Amazon that shows amps.  80% would be 16 amps.  I never go over that.

I ran the electric a while back before mining, so it's what I got.  Eventually I'd like to get 220 setup somewhere but kind of out of space on the box.

bretthexum, when you wrote "I did a similar setup and couldn't run 220 for variety of reasons.", are you referring to the new NVIDIA CMP 220HX?

Thanks

Nope, just had some issues with my box and house and didn't want to spend a fortune at the time.  I set up the 20 amp circuits 3-4 years ago, before I even started mining

I was referring to 220/240v circuit (which are basically the same)

[philipma1957]

Thank you philipma1957 for your answer, really helpful! Let me answer your questions:

Question 1) So first question I have to attempt to fix the fuck up is to ask where is the  200 amp box?


The 200 amp box is installed in the washing room in my basement next to the garage where I set up my racks for mining.

Question 2) second question I have to attempt to fix the fuck up is do you have 4 separate circuits each one for 20 amps.

Yes my electrician installed on my panel 4 separate circuits each one for 20 amps.

Question 3) third question I have to attempt the fuck up if there are 4 circuits going to 4 outlets how many rigs do you have.

Yes so my thought processes is that for each circuit of 120 V and 20 A, the maximum wattage I can safely pull is 1920 watts (after applying 80% rule) or 16 Amp and I presently have 2 mining rigs pulling 1260 Watts (I see it thanks to the PDU with the meter integrated). I am planning to add a third mining rigs (6 GPUs GTX 1660 Super) which will be pretty close to 1920 Watts then I repeat that for each circuit/outlet.

Question 4) fourth question is since he switched out a 150 amp box for a 200 amp box do you have empty slots in the new box.

Yes in my new electrical panel I now have 13 empty/available slots for new breakers.

5) fifth question is how many rigs using how much power do you have right now.

Now I have 2 mining rigs using in average 600 Watts each and soon I will have 2 more mining rigs same type (6 GPUs, total: 600 Watts each rig).

I really explained to the electrician that I wanted to mine cryptocurrency and that I would like to have 10 kW in my garage available for that and this is what he sold me. Yea I am a newbie  

Thanks for your answer.
 

You are not going to be able to safely run 3 rigs at 1920 watts per circuit.

1920/2200 =  87.27%

WTF. where did 2200 come from. 20 x 110 = 2200 and once you have 4 circuits pulling 1920 volts  you will certainly have voltage sag to 107-115 in the hotter months.


So those circuits assuming the wires are 10 gauge and not 12 gauge could maybe do 2400 x .8 = 1920 watts.

MY suggestions are  kick the electrician in the butt as he provided you less than 10kwatts.

you are pretty certain to be able to do 20 x 110 x .80 = 1760 watts if the wires are 10 gauge.

I will rant like mad as electricians are fucking amateurs you are a constant endless hard load on those circuit.

and your guy cut fucking corners.

If I were you I would do 3x 5 card rigs which if you are correct drops you to a safe number.

you said 1260 watts on a meter for 12 cards.  so

10/12 x 1260 = 1050 for 10 cards x 1.5 = 1575 watts for 15 cards.  that will work for you.

Other things you can do tear  his work out on 3 of  the 4 breakers

the 4 th you leave.

the 3 you up grade to 20 amp 220/240 service. you need 3 more breaker slots as each 220/240 line uses 2 break slots.

so you end up with 3 x 2 = 6 slots to run 3x 220/240 breakers

and keep the one he did.

change the sockets to 20 amp 220/240 sockets

so the 220/240 will do

220 x 20 x .80 = 3520 watts that is 5 rigs on each circuit

[JayDDee]

I see things a little differently.

110V is fine for GPU rigs.  220V would have been better for mining, and necessary for ASIC mining,
but 110 is more compatible with most houshold appliances in North America.

120V/20 Amp circuits likely have 12 gauge wiring, not 10, so converting those circuits to 220V is a no-go.

Three rigs @ 600W each for a total of 1800W is fine for a 20A circuit with a safety margin.
However, that's not an efficient rig design. Two rigs with either more GPUs or bigger GPUs
would be more efficient.

[miner29]

I see things a little differently.

110V is fine for GPU rigs.  220V would have been better for mining, and necessary for ASIC mining,
but 110 is more compatible with most houshold appliances in North America.

120V/20 Amp circuits likely have 12 gauge wiring, not 10, so converting those circuits to 220V is a no-go.

Three rigs @ 600W each for a total of 1800W is fine for a 20A circuit with a safety margin.
However, that's not an efficient rig design. Two rigs with either more GPUs or bigger GPUs
would be more efficient.

Sure it can work for 220v.  More importantly 220v is more efficient in the psu. (go look at the efficienty charts). Thats the reason to go higher voltage.  The wire is rated to 600V.  You can run 20amps of either on it.  It requires diffenent breakers and outlets but the wire is the same. So keeping at 80% of breaker size (standard rule of thumb safety) 120v = 1860watts and 220v = 3840watts...all over the same 12-2 wire and on the appropriate 20a breaker for each. Check the NEC code book.

[JayDDee]

I see things a little differently.

110V is fine for GPU rigs.  220V would have been better for mining, and necessary for ASIC mining,
but 110 is more compatible with most houshold appliances in North America.

120V/20 Amp circuits likely have 12 gauge wiring, not 10, so converting those circuits to 220V is a no-go.

Three rigs @ 600W each for a total of 1800W is fine for a 20A circuit with a safety margin.
However, that's not an efficient rig design. Two rigs with either more GPUs or bigger GPUs
would be more efficient.

Sure it can work for 220v.  More importantly 220v is more efficient in the psu. (go look at the efficienty charts). Thats the reason to go higher voltage.  The wire is rated to 600V.  You can run 20amps of either on it.  It requires diffenent breakers and outlets but the wire is the same. So keeping at 80% of breaker size (standard rule of thumb safety) 120v = 1860watts and 220v = 3840watts...all over the same 12-2 wire and on the appropriate 20a breaker for each. Check the NEC code book.

I agree with everything you said and I'll take your word about the NEC code.
I didn't look anything up but I was concerned about the suggestion that if 10 gauge wiring was installed
a conversion to 220V would be trivial. My point was more about the actual wiring than the code.
But it's moot now if, as you say, 12 gauge can handle a 220V circuit.

[philipma1957]

I see things a little differently.

110V is fine for GPU rigs.  220V would have been better for mining, and necessary for ASIC mining,
but 110 is more compatible with most houshold appliances in North America.

120V/20 Amp circuits likely have 12 gauge wiring, not 10, so converting those circuits to 220V is a no-go.

Three rigs @ 600W each for a total of 1800W is fine for a 20A circuit with a safety margin.
However, that's not an efficient rig design. Two rigs with either more GPUs or bigger GPUs
would be more efficient.

Sure it can work for 220v.  More importantly 220v is more efficient in the psu. (go look at the efficienty charts). Thats the reason to go higher voltage.  The wire is rated to 600V.  You can run 20amps of either on it.  It requires diffenent breakers and outlets but the wire is the same. So keeping at 80% of breaker size (standard rule of thumb safety) 120v = 1860watts and 220v = 3840watts...all over the same 12-2 wire and on the appropriate 20a breaker for each. Check the NEC code book.

I agree with everything you said and I'll take your word about the NEC code.
I didn't look anything up but I was concerned about the suggestion that if 10 gauge wiring was installed
a conversion to 220V would be trivial. My point was more about the actual wiring than the code.
But it's moot now if, as you say, 12 gauge can handle a 220V circuit.

Yes 12 gauge is fine for a 20 amp 220/240 circuit.

Since I do not know what he used 12gauge or 10 gauge (bet you he used 12 gauge) 12 is way easier to  use then 10.

My assumptions are 20 x 110 x .8 = 1760 watts in the summer months not 20 x 120 x .80 = 1920

the op said 2 rigs are 1260 so 3 are 1890 and 1890 is just over my assumption that his safe number is 1760.

A lot depends on heat and wire length when you are near the line.

He has zero need to be near the line of overload.

He has spare circuits and upgrading 3 lines to 220/240 will make him be able to run 20 x 220 x .8 = 3520 with the 12 gauge that is most likely in this install .  It allows him to bump rigs to 8 cards so 3 x 8 = 24 cards a ciruit.

if 12 cards were 1260 watts than 24 cards are 2520 watts tack on 80 more 2500 is way under 3520. just better for future expansion.

3 x 3520 = 10560 upgrade to 220/240

and 1 x 1760  for the unchanged 110/120

if he wants to save some coin

upgrade 2 and keep 2

thus

2x3520 upgrade

2x1760 kept the same

total of 10560 watts.

actually this makes better sense  he has plenty of power and it costs less.

 the needs are:

2 more slots in the box.
2 20 amp 220/240 volt breakers
2 20 amp 220/240 receptacles

a good compromise for op.

[Didz]

I did a similar setup and couldn't run 220 for variety of reasons.

I got a nice 20 amp Tripp Lite PDU from Amazon that shows amps.  80% would be 16 amps.  I never go over that.

I ran the electric a while back before mining, so it's what I got.  Eventually I'd like to get 220 setup somewhere but kind of out of space on the box.

bretthexum, when you wrote "I did a similar setup and couldn't run 220 for variety of reasons.", are you referring to the new NVIDIA CMP 220HX?

Thanks

Nope, just had some issues with my box and house and didn't want to spend a fortune at the time.  I set up the 20 amp circuits 3-4 years ago, before I even started mining

I was referring to 220/240v circuit (which are basically the same)

This is something I don't understand the 220/240V, in North America it's 240V why 220V? What's the difference? Thank you

[philipma1957]

I did a similar setup and couldn't run 220 for variety of reasons.

I got a nice 20 amp Tripp Lite PDU from Amazon that shows amps.  80% would be 16 amps.  I never go over that.

I ran the electric a while back before mining, so it's what I got.  Eventually I'd like to get 220 setup somewhere but kind of out of space on the box.

bretthexum, when you wrote "I did a similar setup and couldn't run 220 for variety of reasons.", are you referring to the new NVIDIA CMP 220HX?

Thanks

Nope, just had some issues with my box and house and didn't want to spend a fortune at the time.  I set up the 20 amp circuits 3-4 years ago, before I even started mining

I was referring to 220/240v circuit (which are basically the same)

This is something I don't understand the 220/240V, in North America it's 240V why 220V? What's the difference? Thank you

it is 110/120

it is 220/240

power sag happens in summer
power sag happens on high loads

so 120 can sag to 110

240 can sag to 220

if you push a line say a 120 volt 20 amp line with 12 gauge wire running 1890 watts.

it will certainly sag in voltage if you run 24/7/365

but your can can handle a sag to 110


if you push a 240 volt  20 amp line with 12 gauge wire you need to get to over 3780 watts to push it hard as the 120 line above.

My home in the winter is around 242 volts in the main box at the 2 hot lines from the street transformer.
MY home in the summer at  3 pm  on a hot day is around 235 volts in the main box at the 2 hot lines from the street transformer.

if I go to the 240 outlets running the gear in my house in winter maybe 239-241 but in the summer 232-233.

these are typical sag numbers for my house.

So if you run your lines 24/7/365 with the loads you speak of you may find you are undersized in July and August.

My suggestion to upgrade 2 of the 4 lines should work very well for you.

[Didz]

Thank you philipma1957 for your answer, really helpful! Let me answer your questions:

Question 1) So first question I have to attempt to fix the fuck up is to ask where is the  200 amp box?


The 200 amp box is installed in the washing room in my basement next to the garage where I set up my racks for mining.

Question 2) second question I have to attempt to fix the fuck up is do you have 4 separate circuits each one for 20 amps.

Yes my electrician installed on my panel 4 separate circuits each one for 20 amps.

Question 3) third question I have to attempt the fuck up if there are 4 circuits going to 4 outlets how many rigs do you have.

Yes so my thought processes is that for each circuit of 120 V and 20 A, the maximum wattage I can safely pull is 1920 watts (after applying 80% rule) or 16 Amp and I presently have 2 mining rigs pulling 1260 Watts (I see it thanks to the PDU with the meter integrated). I am planning to add a third mining rigs (6 GPUs GTX 1660 Super) which will be pretty close to 1920 Watts then I repeat that for each circuit/outlet.

Question 4) fourth question is since he switched out a 150 amp box for a 200 amp box do you have empty slots in the new box.

Yes in my new electrical panel I now have 13 empty/available slots for new breakers.

5) fifth question is how many rigs using how much power do you have right now.

Now I have 2 mining rigs using in average 600 Watts each and soon I will have 2 more mining rigs same type (6 GPUs, total: 600 Watts each rig).

I really explained to the electrician that I wanted to mine cryptocurrency and that I would like to have 10 kW in my garage available for that and this is what he sold me. Yea I am a newbie  

Thanks for your answer.
 

You are not going to be able to safely run 3 rigs at 1920 watts per circuit.

1920/2200 =  87.27%

WTF. where did 2200 come from. 20 x 110 = 2200 and once you have 4 circuits pulling 1920 volts  you will certainly have voltage sag to 107-115 in the hotter months.


So those circuits assuming the wires are 10 gauge and not 12 gauge could maybe do 2400 x .8 = 1920 watts.

MY suggestions are  kick the electrician in the butt as he provided you less than 10kwatts.

you are pretty certain to be able to do 20 x 110 x .80 = 1760 watts if the wires are 10 gauge.

I will rant like mad as electricians are fucking amateurs you are a constant endless hard load on those circuit.

and your guy cut fucking corners.

If I were you I would do 3x 5 card rigs which if you are correct drops you to a safe number.

you said 1260 watts on a meter for 12 cards.  so

10/12 x 1260 = 1050 for 10 cards x 1.5 = 1575 watts for 15 cards.  that will work for you.

Other things you can do tear  his work out on 3 of  the 4 breakers

the 4 th you leave.

the 3 you up grade to 20 amp 220/240 service. you need 3 more breaker slots as each 220/240 line uses 2 break slots.

so you end up with 3 x 2 = 6 slots to run 3x 220/240 breakers

and keep the one he did.

change the sockets to 20 amp 220/240 sockets

so the 220/240 will do

220 x 20 x .80 = 3520 watts that is 5 rigs on each circuit

Thank you philipma1957 for taking the time to explain me all that but I'm confused. My electrician told me that each circuit/outlet is 120 V not 110V. I don't understand why you are referring to 110V, I live in Canada I think it's always 120V or 240V we use no?

I told him that I calculated with the 80% rule that I shouldn't go above 1920 Watts and he told me that I can go up to 2000 Watts no problem. He told me he's been electrician for 31 years  

I verified the wires for each 120V/20A circuit are 12 gauge .

It's good to know I can upgrade but I think I will nevertheless try to plug 3 mining rigs (waiting for the Veddha rack shipped from Hong Kong for the 3rd mining rig) on one 120V/20A if I don't go above 1920 Watts. I will monitor it closely.

[JayDDee]

Thank you philipma1957 for taking the time to explain me all that but I'm confused. My electrician told me that each circuit/outlet is 120 V not 110V. I don't understand why you are referring to 110V, I live in Canada I think it's always 120V or 240V we use no?

The CSA standard is for 120V and 240V, It doesn't mean you always get that at the plug. A lower voltage increases
the current for the same power level so it's safer to calculate for 110V.

[Didz]

I see things a little differently.

110V is fine for GPU rigs.  220V would have been better for mining, and necessary for ASIC mining,
but 110 is more compatible with most houshold appliances in North America.

120V/20 Amp circuits likely have 12 gauge wiring, not 10, so converting those circuits to 220V is a no-go.

Three rigs @ 600W each for a total of 1800W is fine for a 20A circuit with a safety margin.
However, that's not an efficient rig design. Two rigs with either more GPUs or bigger GPUs
would be more efficient.

Thank you so much JayDDee, I really appreciate to have different opinions!
I thought I well prepared my electrical infrastructure but turn out it's much more complicated than I thought.

[philipma1957]

Thank you philipma1957 for your answer, really helpful! Let me answer your questions:

Question 1) So first question I have to attempt to fix the fuck up is to ask where is the  200 amp box?


The 200 amp box is installed in the washing room in my basement next to the garage where I set up my racks for mining.

Question 2) second question I have to attempt to fix the fuck up is do you have 4 separate circuits each one for 20 amps.

Yes my electrician installed on my panel 4 separate circuits each one for 20 amps.

Question 3) third question I have to attempt the fuck up if there are 4 circuits going to 4 outlets how many rigs do you have.

Yes so my thought processes is that for each circuit of 120 V and 20 A, the maximum wattage I can safely pull is 1920 watts (after applying 80% rule) or 16 Amp and I presently have 2 mining rigs pulling 1260 Watts (I see it thanks to the PDU with the meter integrated). I am planning to add a third mining rigs (6 GPUs GTX 1660 Super) which will be pretty close to 1920 Watts then I repeat that for each circuit/outlet.

Question 4) fourth question is since he switched out a 150 amp box for a 200 amp box do you have empty slots in the new box.

Yes in my new electrical panel I now have 13 empty/available slots for new breakers.

5) fifth question is how many rigs using how much power do you have right now.

Now I have 2 mining rigs using in average 600 Watts each and soon I will have 2 more mining rigs same type (6 GPUs, total: 600 Watts each rig).

I really explained to the electrician that I wanted to mine cryptocurrency and that I would like to have 10 kW in my garage available for that and this is what he sold me. Yea I am a newbie  

Thanks for your answer.
 

You are not going to be able to safely run 3 rigs at 1920 watts per circuit.

1920/2200 =  87.27%

WTF. where did 2200 come from. 20 x 110 = 2200 and once you have 4 circuits pulling 1920 volts  you will certainly have voltage sag to 107-115 in the hotter months.


So those circuits assuming the wires are 10 gauge and not 12 gauge could maybe do 2400 x .8 = 1920 watts.

MY suggestions are  kick the electrician in the butt as he provided you less than 10kwatts.

you are pretty certain to be able to do 20 x 110 x .80 = 1760 watts if the wires are 10 gauge.

I will rant like mad as electricians are fucking amateurs you are a constant endless hard load on those circuit.

and your guy cut fucking corners.

If I were you I would do 3x 5 card rigs which if you are correct drops you to a safe number.

you said 1260 watts on a meter for 12 cards.  so

10/12 x 1260 = 1050 for 10 cards x 1.5 = 1575 watts for 15 cards.  that will work for you.

Other things you can do tear  his work out on 3 of  the 4 breakers

the 4 th you leave.

the 3 you up grade to 20 amp 220/240 service. you need 3 more breaker slots as each 220/240 line uses 2 break slots.

so you end up with 3 x 2 = 6 slots to run 3x 220/240 breakers

and keep the one he did.

change the sockets to 20 amp 220/240 sockets

so the 220/240 will do

220 x 20 x .80 = 3520 watts that is 5 rigs on each circuit

Thank you philipma1957 for taking the time to explain me all that but I'm confused. My electrician told me that each circuit/outlet is 120 V not 110V. I don't understand why you are referring to 110V, I live in Canada I think it's always 120V or 240V we use no?

I told him that I calculated with the 80% rule that I shouldn't go above 1920 Watts and he told me that I can go up to 2000 Watts no problem. He told me he's been electrician for 31 years  

I verified the wires for each 120V/20A circuit are 12 gauge .

It's good to know I can upgrade but I think I will nevertheless try to plug 3 mining rigs (waiting for the Veddha rack shipped from Hong Kong for the 3rd mining rig) on one 120V/20A if I don't go above 1920 Watts. I will monitor it closely.

Well living in Canada with cooler temps for the summer may work for you.  But trust me voltage sag is a well known factor all over the world..  While you may spec to 120 you will find you range under and over that 120

Since your mining gear psu's can handle more power I don't worry if you drift upwards to 125 or so it is if you drop to

lets see 115 is

115 x 20 x .8 = 1840 and your rigs pull 1890  do that for 1 hot week you will pop breakers.

 but hey your rigs your home your $$.  Check the voltage with this unit or one like it :


https://www.amazon.com/BALDR-Electricity-Monitor-Consumption-Killawatt/dp/B07Y1SLZ8W/ref=sr_1_1_sspa?

it will tell you your volts if you sag under 115 volts you are in the danger zone.

I am interested in your readings in your home.

you said you have a meter.

see if it shows volts with 1 rig attached
see if it show volts with 2 rigs attached.
see if it shows volts with 3 rigs attached. make the last rig have 4 cards so as to not over load the meter.
see if there is a sag.

if you read 121 then 120 then 118 you may have issues in the summer.

btw the k-watt-meters like my like are not meant to run 24/7/365 with watts over 1200 but you can exceed 1800 for a short time like 20 minutes which would let you see if the line sags under load.

You could be in a very well wired area and not get a lot of sag.

I just checked my volts on my 120 lines they are 121.7
I just checked on my 240 lines they are 243.4

It is cool in NJ ,USA so grid is not stressed I tend to run in this level to the heart of the summer. I will be 117 and 234 this summer.

[Didz]

I see things a little differently.

110V is fine for GPU rigs.  220V would have been better for mining, and necessary for ASIC mining,
but 110 is more compatible with most houshold appliances in North America.

120V/20 Amp circuits likely have 12 gauge wiring, not 10, so converting those circuits to 220V is a no-go.

Three rigs @ 600W each for a total of 1800W is fine for a 20A circuit with a safety margin.
However, that's not an efficient rig design. Two rigs with either more GPUs or bigger GPUs
would be more efficient.

Sure it can work for 220v.  More importantly 220v is more efficient in the psu. (go look at the efficienty charts). Thats the reason to go higher voltage.  The wire is rated to 600V.  You can run 20amps of either on it.  It requires diffenent breakers and outlets but the wire is the same. So keeping at 80% of breaker size (standard rule of thumb safety) 120v = 1860watts and 220v = 3840watts...all over the same 12-2 wire and on the appropriate 20a breaker for each. Check the NEC code book.

I agree with everything you said and I'll take your word about the NEC code.
I didn't look anything up but I was concerned about the suggestion that if 10 gauge wiring was installed
a conversion to 220V would be trivial. My point was more about the actual wiring than the code.
But it's moot now if, as you say, 12 gauge can handle a 220V circuit.

Yes 12 gauge is fine for a 20 amp 220/240 circuit.

Since I do not know what he used 12gauge or 10 gauge (bet you he used 12 gauge) 12 is way easier to  use then 10.

My assumptions are 20 x 110 x .8 = 1760 watts in the summer months not 20 x 120 x .80 = 1920

the op said 2 rigs are 1260 so 3 are 1890 and 1890 is just over my assumption that his safe number is 1760.

A lot depends on heat and wire length when you are near the line.

He has zero need to be near the line of overload.

He has spare circuits and upgrading 3 lines to 220/240 will make him be able to run 20 x 220 x .8 = 3520 with the 12 gauge that is most likely in this install .  It allows him to bump rigs to 8 cards so 3 x 8 = 24 cards a ciruit.

if 12 cards were 1260 watts than 24 cards are 2520 watts tack on 80 more 2500 is way under 3520. just better for future expansion.

3 x 3520 = 10560 upgrade to 220/240

and 1 x 1760  for the unchanged 110/120

if he wants to save some coin

upgrade 2 and keep 2

thus

2x3520 upgrade

2x1760 kept the same

total of 10560 watts.

actually this makes better sense  he has plenty of power and it costs less.

 the needs are:

2 more slots in the box.
2 20 amp 220/240 volt breakers
2 20 amp 220/240 receptacles

a good compromise for op.

philipma1957 you are amazing thanks! I would give you a merit on this forum but I am still a newbie and don’t have merit to give.

So I think I finally understand the whole story about the Voltage. When we say 110V/120V or 220V/240V it’s in fact a range (minimum/maximum) which depend on heat and wire length (and wire gauge I guess).

So yea I think I will do what you suggest “upgrade 2 and keep 2” i.e. keep 2 circuits of 110/120V 20A and upgrade/change for 2X 220/240V 20A circuits.

It’s great doing that because I already bought 2 CyberPower PDU41002 Switched PDU, 120V/20A, 8 Outlets with power meter for my 2 circuits 110/120V 20A. With tax + shipping it's CDN$ 491.09.

So I can keep these 2 PDU and then buy 2 more PDU 240V 20A with integrated power meter for my 2 upgraded 220/240V 20A circuits.

I realized though with 220/240V 20A outlet, there’s no PDU with 5-20R outlets so I won’t be able to use the original power cords from my EVGA 1000W Power Supply Units, I’ll have to order IEC C13 to IEC C14 Power Cables - 14AWG.

Damn there’s so much details with the electrical system for GPU mining rigs.

You rock philipma1957!!!