Sub-Panel Question


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Old 12-26-16, 09:39 AM
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Sub-Panel Question

My main electrical panel is on the exterior wall of my attached garage. I would like to install a 60A or 70A sub-panel in my basement. In order to do this, I will need to run wire over the garage ceiling (where all of the existing circuits are run), down the wall and into a crawlspace that leads into my basement.

My plan was to install a new double pole breaker in the existing panel as a shut off for the sub-panel, run the wire open above the garage ceiling, run conduit down the wall of the garage (since finishing the wall isn't possible), drill through the block and put a pipe chase into the crawl space, run open wire through the crawl space into the basement sub-panel. Does this meet code?

What size and type of cable should be used and do I need to install any additional grounding rods?
 
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Old 12-26-16, 02:23 PM
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Welcome to the forums! For any of your open runs like in the attic you would use cable and secure it as you run along the joists. If you plan on using conduit to run vertically in an unfinished wall, secure a junction box to the conduit and run individual wires down the conduit to another junction box, where you would transition again to cable, securing it to the floor joists of the crawl.

THAT's an ideal situation. We don't know how long the run is. Whether you will be installing a 60 or 70 amp circuit, what your total service ampacity is in the main panel. So a little more information would help.

Remember the subpanel will need to have separated ground and neutral busses and a #6 bare grounding wire from it to two ground rods on the exterior of the building.
 
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Old 12-26-16, 03:14 PM
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Thank you for the warm welcome!

The vertical conduit would be outside of the wall because running the wire through the wall is not possible without tearing out plaster etc. The main reason I thought conduit was the right choice was for protection since the cable would be run in an area that is accessible to people in the garage. What is the reasoning for individual wires in the conduit?

The length of the run is approximately 50'. The main panel ampacity is 100A. For arguments sake, let's say the sub-panel is 60A. What is the correct wire size and type?

I thought that separate grounding rods were only needed if there were two separate structures. Does an attached garage count as a separate structure? I'm not sure if I understand the rules correctly.

Thanks for all of your help!
 
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Old 12-26-16, 03:32 PM
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I thought that separate grounding rods were only needed if there were two separate structures.
That is correct.
Does an attached garage count as a separate structure?
No. You may want to consider running conduit all the way and using THHN/THWN individual wires, two #6 black, one #6 white and one #10 green. Individual conductors are easier to pull in conduit.
 
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Old 12-26-16, 03:46 PM
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Missed the attached part, and it is correct that no grounding rods are necessary.

Ok after the wires run across the garage ceiling they go down a wall. Is this an external wall? It wasn't clear and I assumed a common wall. I would do as Ray suggested and run conduit all the way, make one pull and be done with it.
 
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Old 12-26-16, 04:13 PM
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The wall the vertical run is on is a common wall.

Is there any code stating how high a junction box has to be off of the floor of a garage. Plaster runs all the way down the common wall until the last 8" or so which is the block that I will be going through to get into the crawlspace. If I have a box that low, should it be a weatherproof box to negate any water getting in from hosing down the garage floor etc?
 
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Old 12-26-16, 05:09 PM
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You don't necessarily need a junction box. You may find it easier to use an LB. LB's are weather sealed anyway, so no restrictions on height.
 
 

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