My 220v mining project

[knightslugger]

Let me start off by saying I AM NOT AN ELECTRICIAN (but I did stay at a Holiday Inn Express one night) and electricity scares the living crap out of me (everyone has shoved a butter knife into a wall socket as a child... right?). This project is about me facing fears, learning valuable information about electricity, how electronics utilize electricity, and why large operations use the high voltage they do. The reason i wanted to use 220v power is due largely to the reduced load on the circuits. By pulling half of the current needed to run a peice of equipment from each leg, you are reducing the load on the circuit as a whole. for example on 110v, you're only using one leg of 110v power. on 220, you are using 2 legs of 110v, but you're still drawing 900w total. it splits the load between the two legs as if to pull 450w from one leg and 450w from the other. This enables you to put more equipment on a circuit without overloading the wiring. pretty important if you don't want to burn the place to the ground! with 50A of 220, to get the total usable wattage available, you multiply the amperage by the voltage. in this case 50 x 220 = 11,000 watts. electricians will build in a 15% load de-rating so multiply the wattage by .85 to get the safe maximum which is 9,350 watts, which is 42.5 Amps. PLENTY for my needs.

 

I have this barn. It's older than my grandparents' grandparents. To illustrate, the beams that hold up the structure are solid oak, harvested locally, squared BY HAND, and are joined together by the weight of the structure on top of them. In each support beam is a notch cut into it with an axe, and the brace is wedged into the notch and held in place by the weight of the horizontal beam, and the structure above it. There are no pegs, no nails, no steel joints, nothing that would even resemble modern design. It stands solely on geometry. Amazing really. Anyway, previous owners of the property had added onto the structure with an electric well room and office room to conduct animal/farm business. This office has mostly gone unused by us as we are not in the farming/cattle/kennel business. I decided to use it as a room to house high powered mining equipment. It's cold, it's floored, and is away from my sleeping family.

 

But there's a problem. The only electricity into the room is 110v on farm quality quality wiring. There's a subpanel in the pump room that is not labeled with anything, no conduit (or hardly any to speak of) and a LOT of 220v 2P breakers that run to things I can't easily identify, and I know that it feeds to other buildings on the property. The last owners of the property ran a kennel and had a stove top range in the pump room where i assume they would prepare food and hot water for bathing dogs. Knowing that this is a source for a good 50A 220v circuit, i decided to tap into that with a patch cable and run it into the office and terminate at a 70A service box. This required drilling through walls with rather long augers not knowing what's behind it.

 

Let me tell you, you've never quite lived until you've blindly drilled through a wall hoping to Christ that you don't "find" a live electrical cable.

Anyway, to get the full 50A, i needed to use 6ga stranded copper wire and a 25 foot run of it would get me there. i punched through the wall with a very long (about 3 foot long) 5/8 drill and then finished the hole with a 3/4" bit to fit the 5/8 cable in snugly as i wasn't going to even attempt a chase. The cable is stiff enough i was able to just slide it through all four holes as there is an 8 foot wide hallway that it would be suspended from.

 

 

Finishing up on the oven side of this equation, i used a 30/50A 3 spade angle adapter and configured it for 50A service. the cutout the old owners left me certainly didn't think i'd be using a plug that was the size of my palm when they placed their receptacle. i had to bend the 6ga wire nearly 90* from center to slide it into the outlet but before all that i wanted to make sure the damn thing had power and that the ground was good (also wanted to make sure which breaker it was attached to). i turned off the breaker, tested the ground from a nearby 110v outlet, and then reapplied power to check both legs of energy for voltage. The results were 115 on one leg, and about 117 from the other. I checked this with a multimeter between each leg to get the total 230v and between one leg and the ground to get the 115v. When i was done there, i left the plug hang and shut the breaker off.

 

onto the subpanel.

 

This is where things got hairy. the 6ga feeder had to come down into the subpanel to connect to the busbars (the spades that the breaker connects to). these cables had to be trimmed VERY precisely as they do not bend like speaker wire does and i didn't have a lot of extra cable to play with. INSANELY stiff would be an understatement. After realizing i needed to install the cable clamp on the cable BEFORE sliding it into the subpanel, I trimmed those down and removing only enough of the jacket that i needed to in order to screw into the connector i wired that up. When you're dealing with this much power, it can be over before you even knew what hit you. having exposed bare Connected the ground on the cable to the neutral bus bar since i am not adding a 110v circuit.

 

 

Next came the outlets. The PDU (That's Power Distribution Unit for you PCMR peasants out there :tougue: ) i'm using has L6-30A plugs on the end so I went out and bought a pair of outlets to match. pretty simple things, really, but WOW expensive. I think they were $25 a piece! I made wiring these things harder than i should have, but it works. i didn't want to feed one plug off the other because that just sounds like a horrible idea, so i paired up two leads to each terminal on the breaker and secured them. I then ran the wire into the box (once again forgetting to put the cable clamp on the wires before feeding them) trimmed the wires to length, bent to a 90* and before i secured them i wrapped electrical tap around the sides of the outlet to prevent any sort of trouble should something come into contact with bare wires. like a hand reaching for a connector without killing the power.

 

After quadruple testing that all my contacts were tight, no wire was bare, and that continuity was solid, i turned off the subpanel breaker, turned off the 50A breaker in the other panel that fed the outlet where the range was, and completed my circuit.

the first breaker is always the hardest to flip. I was confident my wiring was good, that nothing was touching anything it shouldn't be, and that everything had been correctly terminated and secured. but there's always that element of WHAT IF... and with this kind of voltage, the what-ifs are generally fatal. The first flip was anti-climactic, as it should be. no pops, no crackles, no hissing, or fires. satisfied that i wasn't going to burn the place down in the next 25 feet, i proceeded into the office where i installed the subpanel. with the cover off, i once again inspected the wiring, took a deep breath, finished my beer, took a step to the left and flipped the switch. Once again, i was presented with an anticlimactic response. nothing happened. no hiss, pop, bang, sizzles, or fires. Checking voltages again to make sure i'm getting the voltage i expected, and that grounding was complete, i proceeded to testing.

 

 

Time to get excited.

 

So i wanted to make sure that the PDUs worked, and that when loaded a little, everything would hold. I ran into the house and grabbed the biggest pile of crap computer i could find: An old (circa 2004) Dell Optiplex 745, a 768x11...something 21" monitor, and a keyboard. Thankfully i had a pair of C13 to C14 cables lying around that i could use to connect to the computer's PSU and the Display's power brick. i switched the computer's PSU to 230v operation, and the display's power adapter was auto-sensing. Everything was ready, i just needed to turn the computer on.

 

and i was blessed by a pleasant blue screen BIOS. Now i know i can run my power hungry ASICs from this power source with little issue. The only problem left to solve is network connectivity, which will be done with a Ubiquity AP and a switch.

 

 

What an adventure. I'm glad i've got the absolute basics of wiring grasped so that i can do projects like this in the future and not kill myself in the process. having a healthy respect for electricity is worth the effort.

 

 

$185 for everything in the cart.

 

[Dujith]

I'm gonna try to get through the whole post. But you made 1 big error at the very start.

110 to 110 is NOT 220v

its 110 * Root(3) = 190,5V and that might be an issue with your PSU's, that also means every other calculation is wrong at this point.

 

Digging through the rest now  

[knightslugger]

1 hour ago, Dujith said:

I'm gonna try to get through the whole post. But you made 1 big error at the very start.

110 to 110 is NOT 220v

North American 220 is 2 legs of 110 each.

[Dujith]

6 minutes ago, knightslugger said:

North American 220 is 2 legs of 110 each.

Your on 3 fase 4 wire delta? Holy crap i have not seen that in many places  thats old.

Then yeah you will have 240V between legs.

Also beware of 1 of the legs when attaching 110V cuz one will be 208V to neutral.

[knightslugger]

47 minutes ago, Dujith said:

Your on 3 fase 4 wire delta?

it's just regular NA single phase 200A service. I hit the contact points of two hots with a multimeter i get 230V. I hit between a hot and a neutral, i get 115V. :SHRUG: 2 legs of 115v and a ground.