Master electrician advise needed

i need to run a wire from my home breaker panel to the 24x30 shop in the back yard approximately 100'. Current wire (aluminum) has a break in it at a 90 degree elbow coming out of the house. I can trace power up to that point then it signals nothing. What size, type wire should I replace it with?

 

Depends on what you have in the shop. If it's a few plugs and lights I'd say 50A min and #8 copper/#4 aluminum. For 100A go #4 copper/#2 aluminum. You can use direct burial "tray cable" for copper or "USE cable" for aluminum. If it's in pipe you'd just use THHN copper. And if it's on a breaker in the house you need a separate ground.

Also, I'll provide my references only cause I never get to:

 

You should be able to determine the amperage of the existing circuit by looking at the circuit breaker in your house that feeds to the shop. Is there a distribution panel in the shop or just a few receptacles and lights on a single circuit? I assume you are looking to simply repair what's there by running a new wire. Copper is better than aluminum because it is not as brittle and won't break easily, especially smaller sizes, but in larger sizes the cost difference between aluminum and copper is significant.

 

Panel in the house is 200 amp and current wire goes to a small distro panel in the shop which is grounded to a rod in the ground right by the shop

Circuit breaker inside the house is currently a 20 amp. Yes just need to replace the feed wire.

 

You're feeding the shop panel with a 20A breaker? While it's ok to do that, I'd recommend stepping up to a 2p50A and feeding it with #8 copper. 2 hots, a neutral, and a #10 ground. With that you dont need to have a ground rod at the shop, all grounding should be done at the service.

 

That's how it was set up when I bought the place. Wanting to do it right this time around. Your advise is what I need. Thanks.

 

Anytime. If you ever want to or might add a welder, compressor or other big loads you can bump that wire up to 3 #4s and a #8 ground and slap a 2p100A on it. If you've got room in the pipe.

 

I heard of aluminum wiring in homes and was told it does break and may short out. Defiantly replace with copper. I’m sure someone here will know what gauge etc.

 

It really depends on the load you will have in the shed. Oh, I'm an electrician.
Also, one reason it may have broken is aluminum wire and possibly aluminum overloaded.
Let us know what load (equipment, lights, tools, .... you want to run in there, it will be much easier to calculate the load, amp, wire size and breaker size.
Also, what is your home service amp? (probably 200A)
Gas heat? gas water heater? gas range? how many AC units?
This all helps determine if your home service is capable of any additional loads (shed loads or new loads)
And how sharp was the 90o bend? was it a sharp bend or radius bend? I've seen some people use a pulling "L" ( I hate pulling "L"s)
And, go back with copper wire.

 

Shop will need 110 only. Minimum usage like lights a few outlets. Nothing major running but powered hand tools. House is 200amp and yes, gas heat, gas water heater, one A/C which is new. House is 2000 sqft. The break is at a sharp 90 coming through a brick wall rurning straight down then another 90 going under a sidewalk.

 

If that's all you need out there, I would (if it were me) run 2 x 20 amp circuits 2 x hot, (black and red) 1 x neutral, (white) 1 x ground, (green) You will need another 20 amp breaker.
Is it PVC pipe? If so, what size (prob 3/4" or larger, I hope)
If this is the case, 4 x #10 THHN wire, #12 THHN will work since its only 100' away, but #10 would be nice.
If there is a junction box in the building, you will just make joint to lights, receptacles as wanted.
You will need to take the Green to the ground rod.
Hope this helps.

 

Oh another reason to pull 2 circuits, if at any time you have that one wire you are using break, you will have a spare.

 

3/4" pvc but I'm going to go bigger since there is already an issue with the old pipe plus it's very shallow

 

Since you're going to run new pipe, 1" should be good.
Use weather prof junction boxes outside where it goes down into the ground, it's much easier to feed the wire or pull, depends on which way you pull.
Once in the ground, use radius 90o's in the ground.
When pulling new wire in, use wire pull lubricant. and don't be stingy with the lube. Squirt as much as you can in the pipe before pulling.

 

So i am also a master electrician with my own contracting business. So what you should do is not listen to any of these people. Call your local inspection agency and they should be able to tell you who is a good contractor. You will then call the top 3 and get estimates for what you are looking to do. Pick the estimate that you are most comfortable with and pay them to do the work. You should not do potentially deadly work without proper licenses and permits.

 

True if trying to wire/rewire the whole house, addition, major equipment or multi story building or something else.
A small 20A branch circuit? The permit would cost more than the material.
If the OP wants to do the work himself, nothing wrong with that as long as he understands the potential risks.
Most states do not require a home owner to hire an electrical contractor if a home owner wants to do work on his own property.

 

Plus inspectors wont recommend contractors.

 

Very true

 

Don’t use aluminum for this circuit! It’s a fire hazard. Aluminum wiring expands and contracts as it heats/cools and will “wiggle” out of the connector (unless you use crimped terminations which sounds unlikely with what you’re describing). Use copper wire. If you run it in conduit, use THWN (not THHN unless it is dual rated THHN/THWN). Voltage drop could exceed 3% with a 14-15 amp load at 100’. To be sure you don’t have voltage drop issues, use #10 copper for a 20A circuit instead of #12. Include a ground wire of the same size with your circuit conductors.

And it sounds like the wiring in your shop goes directly to receptacles and lights. If so, this circuit can not exceed 20A unless you want to install a sub-panel in the shop.

I’m a licensed professional engineer (electrical) and have designed building electrical systems for over 30 years.

 

It really depends on the load.
10A load, #12 will be good.
16A load (max allowed on 20A circuit @80% unless derating for conduit fill) #10
Most all THHN wire is dual rated THHN/THWN these days.
But yes, I do recommend #10 at 100' or more.

 

I agree. I was going to reply about the voltage drop. 100 feet isn’t terrible but I’ll let you do the math since you’re an engineer. I am a Journeyman Substation. Master technician. I have made a lot of outdoor cables pulls, both DC and AC and I have never pulled aluminum.
Go with copper.

 

Also, if you are comfortable working with electricity, understand how to isolate and keep yourself safe I see no reason for you to contract this out. It’s really a simple project.
Now, permits have always made me wonder. I haven’t really ever needed to pull any but I have quite a few neighbors that finished their basements and I’m confident a few never pulled a permit. It’s makes me wonder if you can get yourself in an insurance bind if they pinpoint the work as the reason for fire etc.

 

Any idea what your single phase voltage was out there to begin with? If you were at 120 and assume a 3 percent voltage drop, that’s less than 4 volts. 116 volts is low but really the regulated bandwidth is 114-126 so you’re still good. Much lower than that and you could have voltage issues.

 

I don't. It hasn't worked since we've been there. I've just used the space for storage.

 

I think you’ll be fine but throw a meter on it when it gets energized.

 

Lots of good advice here, but most of it seems like overkill for what you are trying to do.

If you have a 20 amp double breaker there now, then you are running 220 volts to the shop, replacing the broken wire with number 10 copper; two wires for the feed, a neutral, and a ground.

I was an electrician 40 years ago, so I do not know current code very well, but I think the person who said that you should run a ground from your main service to the panel in the shed is right. If you do that then you don't connect to the ground rod by the shop. Disconnect that ground rod from the panel in the shop.

Since you plan to install new conduit, it is easier to slide the sections of pipe onto the wire individually before gluing them together. You can then drop the conduit into the ditch and cover it up with the wires already inside.

 

Oh I just read where you have a distribution panel in your shop. I missed that the first time through. Do you know what the amp rating is for the shop panel? Does it have a main breaker? Those panels are usually rated for 60A but you need to confirm. If it is rated 60A you could feed it with 60A breaker but that might be overkill for what you need. If it was mine in your situation, I would install a 40A/2-pole circuit breaker in the house panel and feed the shop panel with 2#8AWG copper (phase conductors), 1#8AWG copper (neutral conductor), and 1#10AWG copper (ground). That will fit in a 3/4" conduit. The #8AWG copper conductor is good for 50 amps so that will take care of any voltage drop issues since it has a higher rated ampacity (lower impedance) than you need and you will be protecting it with a 40A breaker. You can leave the ground rod and ground connection to the shop panel...it's actually a good thing...just make sure there is not a neutral to ground bond (or jumper) between the ground and neutral busses in your shop panel. If so, remove the jumper since that will cause nuisance tripping of your ground fault devices.

@Geezer suggestions above are good if you want the minimum. I'd still leave the ground rod connection but remove any neutral-ground jumpers.

 

CITY? CES?

 

Mayer electric?