Feed wire sizing to my garage

Not exactly on topic but ..

I just changed out my workshop (cubby hole) lighting for led flurecesent fitting of 50w, it has a maintained live and a battery that will keep half the lights on for upto 3h if the power drops might be worth considering if your going to be working at night in the dark surrounded by spinny and sharp things :)

They have got a lot cheeper, and you can get a small bulk head light as a very cheep one juat to give enough light to find your way out.

Stuart

Magnetic contractors are your friend in a power outage....
 
Hate to point this out, but.... It's never a good idea to sit and think about how little you are going to do and then subtract from what you think you need for power in a shop. If you are not going to work in the shop, then forget about it. Put up a sky light to get some light in and start building shelves to store crap on. It's typically easier to begin building shelves in the middle of the floor so you can store as many things you will never use again on them. OR you can do it with the idea that you WILL be working out there. And buying equipment that will consume more power and build to accommodate it now.

I am not saying to get a new 400 amp service put in, but running 3 12 gauge runs of Romex ain't gonna cut it either.

First off, how big of a panel is in the house? You can't exceed that so don't bother trying to. If the main is 100 amp, then a 200 amp sub panel on it fed from a 200 amp breaker is pointless. You can go 100% of the main, but no more than that. and I wouldn't do that. 75% is where I would stop and 80% is a hard limit in my book. Code's in your area may vary, so don't think I am quoting regulation, I am not.
So lets size the wire for 80 AMP.

Book says that you are looking at 4 gauge copper but that is for 50 foot. I would go to 2 gauge and call it good for that distance.
Cutting it in is easier that you might think.
Use a rototiller and just go from one building to the other over and over again. Have a couple friends or kids walk behind you with shovels and clean out the trench until you are 2 foot or so down and lay the pipe. Cover it up, put in the wire and go to town.
get a used panel and an ebay breaker to feed it power and you are off to the races.
Wire garage to the sub panel you installed and you are golden.

If there is at any point, any doubt as to your abilities to do this work, stop and call a professional.
 
Forget ebay for panels.

We got our 200 amp capable subpanel with a good supply of breakers at home depot for 70 bucks.

The box stores have different sizes from small to large with breakers for decent money.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
We got our 200 amp capable subpanel with a good supply of breakers at home depot for 70 bucks.

One might, also, consider wiring in a Main Breaker Load Panel, if there is any thought that over 100 Amps will be needed. When I re-wired my (soon to be) workshop, I did so, knowing that an addition of a phase converter to existing lights and whatnot might exceed the capacity. If I find 100 A won't cut it, all I'll need to do is change some wiring, add a meter base, and pay the utility to connect.

NOTE: That wiring a subpanel and wiring a main breaker fed from the utility are two different animals. If you don't know the differences, you might want to get professional help...
 
My garage is about 50 ft from the house. I ran 2 #4 wires for each leg. I had a tiny panel in there until I got into the lathes and mills. I found a 100A panel on CL and upgraded and have been very happy since. I have almost 0 voltage drop from the house and have never been able to blow the 100A breaker in the house, even when welding 3/8" aluminum. I suggest you go bigger than you think you need. Overkill is good in this situation.

Chris
 
If you ran 2-#4 per phase in parallel then it's a code violation. NEC prohibits conductors smaller than 1/0 in parallel (310.10 (H)(1)). Also, most lugs on breakers and panels are not rated for more than one wire per terminal so you would have to splice them to a larger wire to connect to the panel.
I'd hate to see someone try it and get shot down in a building inspection.
 
If you ran 2-#4 per phase in parallel then it's a code violation.

You would probably spend about 1/3 more in wire cost (minimum) to run 2-#4 wires vs., say, a #1 wire, which is roughly (but not quite) equivalent. Check your local codes, one #2 would probably be sufficient and meet code....
 
If you ran 2-#4 per phase in parallel then it's a code violation. NEC prohibits conductors smaller than 1/0 in parallel (310.10 (H)(1)). Also, most lugs on breakers and panels are not rated for more than one wire per terminal so you would have to splice them to a larger wire to connect to the panel.
I'd hate to see someone try it and get shot down in a building inspection.

Bummer. My buddy that wired it is a licensed electrician, so I thought he knew what he was doing. Maybe he just cut a corner to save bucks in my situation.

Thanks for the info.
Chris
 
Bummer. My buddy that wired it is a licensed electrician, so I thought he knew what he was doing. Maybe he just cut a corner to save bucks in my situation.

Thanks for the info.
Chris

Very likely so..... he may have had a surplus of #4 wire left from a particular job. It is unlikely that (after the fact) any inspector is going to be rummaging in your panel. If it works, enjoy what you have...... others, that may have an inspector driven solely by the black and white of the NEC may not be so forgiving..... IMHO, everything should be driven by common sense, an all to rare animal in this "Nation of Laws."
 
You have a baby? Well, I can see why shop wiring is not a high priority budget item <G>.

For my shop, I have a 15A 240v circuit that runs VFD's for a drill press, lathe, and mill. At 3.6KW, I could run 2 at once, but I'm not nimble enough to do that.

All the outlets (12?) are on one 15A 120V circuit. A baby MIG is on that. Lights are on a shared house circuit.

I know, "more is better", "better now than to have to upgrade later", yada yada. But if I were you, I would pull a 12-3 wG through the conduit you have & put in a sub panel large enough to hold a 15A 240 & 2 15A 120's. 15A is big enough and 14ga wire is so much easier to handle than 12ga. In other words: what you said.

This could satisfy your needs for years, depending. Could probably even have a moderate (20 gal) compressor on it.

Bob
 
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