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Arrow Hart Murray main panel and adding a subpanel on the new building

Arrow Hart Murray main panel and adding a subpanel on the new building

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  #1  
Old 03-17-13, 09:24 PM
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Arrow Hart Murray main panel and adding a subpanel on the new building

Hey all,

The workshop build is coming along nicely, and we're planning for the electric service.

The house itself is served by a panel with "Arrow Hart Murray" on the cover, it's an integrated service entrance/meter/breaker panel unit. The breakers are arranged in two horizontal rows, rather than two vertical rows. There's an unused position in the top row next to a single-pole breaker that's unused, and the bottom row has a couple of positions that were previously in use for a pool that is now no longer present.

I'm assuming that a pair of hot wires, a neutral wire, and a ground wire will need to be pulled through the in-ground conduit, and that the two hots and the neutral will need to be sized the same, and that the ground can be sized a little smaller. I'm currently planning on 2AWG THWN for the hots and neutral, and 8AWG for the ground...

The new building foundation does have ground. I assume that even with this, I need to bond the grounds together and to the sub panel itself, but the neutral needs to be non-bonded, letting that occur in the main panel only...

I'm sizing this for 100A total. The workshop will have an air compressor, a vehicle lift, an evap cooler, a couple of circuits of lights, and at least two, possibly four electrical circuits for outlets.
 
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Old 03-17-13, 09:38 PM
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Oh, it looks like SER cable might be a better choice... 2-2-2-4 cable is apparently available, would that actually be the best choice? Conduit will be 2" PVC in the ground...
 
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Old 03-17-13, 09:58 PM
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Depending on the length it might be a little light. However.....SER is not rated for underground use. You would have to use USE (underground service entry) and I don't think you can pull USE thru pipe.

Personally I'd stick with the three #2 THWN's and one #8 THWN. If you were to use aluminum it really should be #1

You will also need ground rods at your shop panel.
 
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Old 03-18-13, 12:45 PM
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Okay, got it, no SER.

When the shop foundation was built the ground was installed...

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I assume that this will be enough...

We're going to find a subpanel that fits nicely between the two studs if possible.
 
  #5  
Old 03-18-13, 02:31 PM
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If that is a Ufer ground you should be fine as far as grounding.

Most panels will fit between standard stud spacing.
 
 

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