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Topic: Upgrading/Adding Home Circuit (Read 126 times)

jr. member
Activity: 234
Merit: 2
February 10, 2018, 01:35:24 PM
#2
I'm having an electrician come to upgrade the main box on my house and add another circuit in the bedroom for my mining equipment.

He's replacing the very old 50A box outside with a new 200A box. I also want another circuit inside to run more equipment.  

I have 10 GPUs right now on 3 systems totaling ~1900W. But I'm not running them on one circuit because I think that's too much for the old 110V(I think??)/20A circuits.

I also need to install a windows A/C unit for the summer.

What type of circuit should I have him add? How many watts can run on a single circuit? I know it depends on the circuit.

Is 240V/30A circuit unnecessary or even practical? I want to be able to expand of course.

I looked up some power distribution units that would be required to use a 240V outlet. They were expensive. I have limited funds.

I know very little.

Please help.
Well lots of electrical questions here.  First lets establish that your wall outlet is 120 NOT 110 (youll need to use the correct voltage for calculations).  1900w is almost to the line of being dangerous by about .17 amps.  The National Electrical Code states that you can only run a load up to 80% of your branch circuit rating (In your case a 20a circuit) for CONTINOUS DUTY. To figure amperage you just take your total watts divide by volts (120v) and the answer is amps. So in your case 1900w/120v = 15.83A on a branch circuit rated for 16A for continuous duty.
To determine total number of watts (for continuous duty on a circuit) you take the Branch rating (amps number on circuit breaker) and times that by 120v. The answer to that is in watts multiply that by 80% (.Cool.  IE: 15a circuit = 15Ax120v=1800w x .8=1440w for continuous duty. (A rig is continuous duty).
The reason for this 80% derating is to prevent excess heating of wiring, circuit breaker and the outlets.  Heat causes metal to warp, form bad connections, breakers to fail and ultimately one or more of these situations results in a fire.  You DONT want a fire in your wall or in your Breaker Panel.
30A circuit are optimal but you can easily use dedicated 20A circuits.  They will each provide 1920w for continuous duty.  You will need a 20a breaker for each circuit. Dont make the mistake of plugging in a 15a power strip into a 20a outlet AND end up exceeding the rating of the 15a power strip by plugging in too much into the power strip. You can use (2) parallel or even (3) parallel duplex outlets on one 20a circuit to give you more outlet availability for each branch circuit.  Each duplex (standard house outlet) has 2 plug ins (sockets). Just make sure you have the electrician mark eat duplex by its circuit breaker number that feeds each so you can keep everything straight.
The A/C unit must (Per the NEC) have its own dedicated circuit breaker feed to the outlet that it is plugged into, again to prevent overheating of the outlet, wiring, breaker. Since youll be running 20a anyway I would go ahead and install a 20a circuit for the window a/c unit so you can go big 120v a/c unit if you have to later. 12awg Wire is cheap enough now.
member
Activity: 155
Merit: 11
February 10, 2018, 12:59:25 PM
#1
I'm having an electrician come to upgrade the main box on my house and add another circuit in the bedroom for my mining equipment.

He's replacing the very old 50A box outside with a new 200A box. I also want another circuit inside to run more equipment. 

I have 10 GPUs right now on 3 systems totaling ~1900W. But I'm not running them on one circuit because I think that's too much for the old 110V(I think??)/20A circuits.

I also need to install a windows A/C unit for the summer.

What type of circuit should I have him add? How many watts can run on a single circuit? I know it depends on the circuit.

Is 240V/30A circuit unnecessary or even practical? I want to be able to expand of course.

I looked up some power distribution units that would be required to use a 240V outlet. They were expensive. I have limited funds.

I know very little.

Please help.
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