# How to do electrical load calculations for Bitcoin mining

Knowing how to do electrical load calculations is essential for running ASIC or GPU miners in your home or office. By doing a load calculation you can see how many miners you can run on each circuit without tripping breakers or blowing fuses.

To calculate your electrical load first you need to know what voltage your circuits are running. If your planning on plugging in a GPU miner in your home or office most likely your working with 120V in Canada. If your planning on using ASICs most Antminers generally use server style PSU (Power Supply Units) that are designed to work with higher voltage, generally 240V in your home or 208V if you have a commercial three phase service.

VoltagePhasesCommonly foundCommon AmpsCommon outlets
120vsingleHome or office15 or 20 amp
240vsingleCommercial15, 20, 30 amp
208VThreeIndustrialComing soon 🙂Coming soon 🙂

Next, you are going to need how many watts your miners are pulling at the wall. For ASIC miners you can get this information from the manufacturer or you can check our ASIC Miner comparison. For GPU miners I have found the watts listed on whattomine.com to be fairly accurate, however, depending on your overclocking or BIOS modifications, it could be significantly different. The most reliable method to check how many watts your rigs are using is to get a simple watt meter. Plug it in and you can see in real time exactly how much each rig is pulling.

Now that you have the voltage of the circuit and the watts of the miner you can do a simple load calculation in Amps.

Circuit Load in Amps = Watts / Voltage

Common examples:

Antminer S9 load on 240v is calculated as 1372 watts / 240V = 5.71 amps

the same miner on a 120v circuit would be a different amp draw.

Antminer S9 load on 120v is calculated as 1372 / 120v = 10.6 amps

It is important to note that circuits can only be loaded up to 80% of their rating. So a 15 amp breaker can only handle 12 amps of steady state load.

I  am more familiar with 240v single phase as my first mine is using this voltage. Once my second location is dialed in I will expand on this article to include more information on 3 phase 208 v circuits.

Important Note: I am not an electrician, these calculations should be used for you to gain a basic understanding of how load calculations work but It is essential to be working with an electrician when building out a mining farm.