200amp service to shop

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Old 04-20-16, 03:25 PM
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200amp service to shop

Hello! I have a small woodworking shop in my barn that was a 100amp service until the underground wires shorted and burned in half(dug up wire to figure out what happened). I had an electrician wire up a new 200amp main shut-off under the meter base on the pole. Now I need to trench and bury a new feed to the barn (130ft). I'm wanting to do this myself to save money. What size wires do you recommend? I was told I need 2.5" conduit to run it thru but someone else said run it in black pipe instead. Its cheaper and easier.
 
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Old 04-20-16, 03:47 PM
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someone else said run it in black pipe instead. Its cheaper and easier.
I can only guess at what black pipe is but it defiantly isn't used for electric unless he was referring to electrical duct. Cheapest easiest is quadplex mobile home cable direct buried no conduit needed except to sleeve it where it enters and leaves the ground.
I had an electrician wire up a new 200amp main shut-off under the meter base
Do you mean a 200 amp breaker box? Many home only use 100 amps are you sure your barn needs 200 amps?
 
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Old 04-20-16, 03:57 PM
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Welcome to the forums!

For 200 amps you need 2/0 copper or 4/0 aluminum. Aluminum will be cheaper. If your looking for easier, direct burial wire or cable would be the easiest, only bad side is you have to bury it 24" down, but if you have easy to dig soil it might not be a big deal.

If you would rather use conduit you must use electrical PVC which is gray. There is no black pipe that is approved for electrical work. You can also use RMC but that would be cost prohibitive. As Ray mentioned, if you direct bury the wire/cable you still need conduit to protect it when it gets higher then 24" in the ground.

You will need two hots, one neutral, and one ground. The ground can be smaller then the other conductors. #4 copper or #2 aluminum.
 
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Old 04-20-16, 04:44 PM
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Thanks for the quick responses! Yeah Ray, the black pipe is well pipe. This is what an electrician used at my brother's house years ago. You're correct about it being a breaker box. Thanks Ray and Tolyn, I appreciate your info. Very informative!
 
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Old 04-20-16, 05:23 PM
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the black pipe is well pipe. This is what an electrician used at my brother's house years ago.
That would be using the term "Electrican" very loosely. What you described is a hack job code violation. I've seen a few hack jobs and one worse than well pipe. A couple years ago I saw mobile home feeder run in 4" corrugated drainage pipe to an outbuilding. The "Electrician" called it conduit!
 
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Old 04-21-16, 03:18 AM
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So is the gray PVC resistant to the heat generated from the wires and that's why it's the only one to use? Just wondering...
 
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Old 04-21-16, 08:13 AM
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It is rated for heat, crush pressure, UV resistance, interior smoothness/friction and electrical non-conductivity.
 
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Old 04-21-16, 10:59 AM
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Now that pipe is out of the way why 200 amps? You had 100 amps before so why 200 amps now? It would take a lot of tools used at the same time and a really big air compressor to need 200 amps. Tell us about all the loads you would have at the same time and if you have electric heat. You could save a bit on wire or cable going down to 100 amps.
 
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Old 04-21-16, 01:50 PM
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The reason for the 200 amps is that I will be able to run more than one machine (table saw, planer, etc.) at a time if someone else is there. Also, I have an on demand electric water heater. It can trip the 100 amp breaker alone if the hot water is ran for an extended period of time. I put it in a few years back to save on space and not have a whole tank of water heated when I don't need it.
 
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Old 04-21-16, 01:54 PM
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Then I'd say your good to go.
 
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Old 04-21-16, 01:55 PM
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Thanks ibpooks for the response. That makes sense.
 
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Old 04-21-16, 02:01 PM
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I hope so Ray. There is one more thing...I have the breaker box on the pole grounded (copper rod in ground) where the meter is. Should the panel box in the barn/shop also have its own grounded rod too?
 
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Old 04-21-16, 02:05 PM
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Yes, the panel in the shop must also have at least one ground rod. You said you had a water heater so if the water supply is metal it must be bonded to the panel also.
 
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Old 04-21-16, 02:17 PM
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All of the plumbing is pex pipe. That way it can freeze solid and not rupture the line in the winter. Do I have to have a bigger gauge copper wire going to the grounding rod with the 200 amp service? It seems like if it shorted it would melt the wire going to ground.
 
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Old 04-21-16, 02:33 PM
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The grounding electrode conductor from the barn panel to the ground rod should be #6 copper; solid or stranded is ok.
 
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Old 04-21-16, 03:37 PM
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Thank you Ray and Ben! Sharing your knowledge is deeply appreciated!
 
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Old 04-21-16, 07:28 PM
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So is the gray PVC resistant to the heat generated from the wires and that's why it's the only one to use? Just wondering...
In addition to what ibpooks has already told you, the gray PVC conduit is UL Listed for electrical purposes and the black polyethylene plumbing pipe isn't. The gray PVC conduit has all sorts of companion UL Listed electrical fittings and boxes available such as elbows and LBs and the black poly plumbing pipe doesn't.
 
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