Lots of asks for a mining rig electricity guide on what is the skinny on electrical and safety of operation info so I felt I would do a write-up here on it but first…


The basics and our rigs

We need the juice, and lots of it! It seems that we can never get enough good wattage to the machines to run that extra last card. So here is how you start knowing what is going on in your house and electrical as well as stay safe and sound. Lets start at the outside of the house.


This is a few, typically 3, large heavy twisted wires that are either coming down from a pole to you roofline or up from the ground if you have underground utilities. These should never be touched nor messed with ever ever. They are not your property and anything that happens to them you are liable for and the electric company WILL come after you for damages. They will supply a total of around 220-240 volts. (sidenote, you can call the electrical CO to trim any dangerously overhanging trees that are near these power lines. This is free and a good idea while we are at this)


Yup again this is not your “property” so dont mess with it unless you want a very large bill. Look up at the head of it. Does it have 2 black and 1 silver wire? Then you have single phase service. Does it have 3 black and a silver? Thats 3 phase. Not many homes will have 3-phase. The rest of this is applicable to single phase service.


This is sometimes present. Sometimes it is just the amps breakers used for this purpose. If it is present it is a fat copper plate that will be inline prior to the circuit box. (It may have a lockhole on it. Do you have yours locked? Not a bad idea.)


Basically the circuit panel. This wonderful box control your ability to eat the electric you need. It is sometimes outside a house, sometimes inside a house. It is always live to some degree unless you have pulled the disconnect or tossed the mains circuits. The main circuits are going to be 200 amps into you house. It might be 2 large fat black double breakers or a long single arm breaker. Unless you asked for an additional 200 amps from the power co, its 200 amps. That disconnects the entire house. You should NEVER work on a panel yourself, however tossing that does kill power to the rest of the panel. It does not mean you cannot get electrocuted if you open the panel. You can/will if you go north of the 200 amp breakers. Its prolly instant massive heartattack death so lets not do that.

Now you will see your individual breakers. These will be labeled 15 or 20 amp (on the breaker) and a few 30 or 40 amp ones also (stove, hottub, washer/dryer) Most modern homes are 20 amps. Most older homes are 15 amps. There is some important reasons to note this well. Now is also the perfect tome to clear-up the crappy label job that installing electrician surely did. Use masking tap and a sharpie to go tape over to the sides and write in which plugs are effected. Use both room and a number starting with 1-X. Then mark the outlets if you suspect a room is on 2 circuits. (I.E the outlet in the house gets a label bathroom/master/1….the circuit breaker gets a label bathroom/master) That happens in bathroom sharing walls often. Now you wont leave the label on the house outlet….unless you are really OCD….but you will use it to create a nice map of your house and breakers. This should come standard with every house. I have never heard of it coming with any house.

So now we know the amps and which breaker controls what. Lets move inside a bit now.

(It may have a lockhole on it. Do you have yours locked? Not a bad idea.)


This is important. For lighting its often 14 for outlets its usually 12. The bigger the wire (12 gauge is larger then 14 just FYI, the less resistance it will present (heat) as electrons flow down it.) You want to check this out especially if you have an old house! Make sure you have the breaker tossed off. Hell pull the 200 amp breaker to be safe. CALL AN ELECTRICIAN. This is if you are going to open a plug and take a measure. Thats however could be less safe then the following.

You can usually see if you crawl in the attic, and see a huge bundle of yellow wires running. Thats your houses electrical romex wires. It will say what gauge on it. If you see nothing but 14….beware. If you see nothing but 12, overkill but fine. If you see both 12 and 14, your like 90% of folks. Its fairly okay to assume the 12 is running to the plugs and 14 to the lights.


Find the Room(s) and outlet(s) that you want to have your rig(s) on. Note them on a photocopy of our overhead map. Write out the WATTS TOTAL your rig will draw. If you have no idea, you can get one with thehttp://makearig.com app, it does wattage calcs.


Lets say you have a sweet 4 card 270 setup like the 1K build So we know that we will be using about 620 watts at the wall. So thats also on 120 volts since I am in the US. If you are in some other location it may well be 220-230 volts.

How much draw can I get from this plug then? Here is how we calculate that. So I have 120 Volts and 20 Amps. That is TOTAL 2400 watts of supply. Now I wont draw over 80% of that, or if I do I will pop the circuit most likely every time I go over 80%! Now that gives us 2400 * .8 = 1920 Watts draw max. If you have a spike to thats above it briefly, its not a huge issue. This is often a breaker tossing problem, not a fire risk (unless you are in a older house, have 14 gauge wires, or some other mysterious configuration that supplies you electric)

So 1920 watts. Lets look at all the other things that are on that outlet. Add them up. Make sure to never have a windows AC or printer/fax/shredder/microwave on the same circuit. If you are smart you wont run anything else off that circuit so you can get the full 1920.

1920/620 = 3.1 So we could put 3.1 rigs on that circuit. (…Its like I must have planned that out right 😉 So we will stick 3 rigs on that puppy then!

Nothing else needs to nor should run on that circuit.


Q. Can I “upgrade” to a 20 amp breaker on a 15 amp slot?

A. No, unless you want to burn down your house while you sleep and kill your family and pets. The answer is more complex then that however and you should contact a licensed electrician to tell you yes or no. Also have the 20 amp breaker already bought so that you can have him install it without some insane part charge while he is out. It will come down to wire gauge and distance.

Q. Can I “upgrade” to a 30 amp breaker on a 20 or 15 amp slot?

A. No, unless death, third degree burns and skin grafts sound like fun to you. This one is very much in the CALL ELECTRICIAN category. Don’t risk it as you prolly dont have large enough wires for the distance. Hence heat. Hence fire. Hence death.

Q. Can I get a new 200 amp service installed on my house, for my garage.

A. Actually prolly yes. You might tell the power co. you have some heavy machine tools to put in your garage.

Q. Does this all apply to 3 phase service?

A. Not a bit. You need to contact an electrician.

Q. What about me! Im in AUS/GB/JP/RU and have 220vac.

A. You will be able to use the same power supply as everyone else (modern PSU’s switch to the correct line voltage) and will have a more efficient use of energy as a result. However you will most likely pay substantially more for electric…so it usually evens out.

Q. Can I install a 30 amp breaker with a 220 vac breakdown? Is that going to work to power my rigs?

A. Yes, but you should have an electrician do all that. Think about the home insurance policy. It doesn’t cover your wire job and death sucks.

Q. Will it be more efficient to run 220 VAC then 120 VAC?

A. Yes. See 1 above as that is your next question 🙂


-120 VAC, 30 Amp circuit = 2880 watts usable

-220 VAC, 30 Amp circuit = 5280 watts usable

-120 VAC, 20 Amp circuit = 1920 watts usable

-220 VAC, 20 Amp circuit = 3520 watts usable

-120 VAC, 15 Amp circuit = 1440 watts usable

-220 VAC, 15 Amp circuit = 2640 watts usable