100 amp subpanel ground


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Old 04-22-12, 01:47 PM
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100 amp subpanel ground

I have a Square D 100 amp QO box and I have the white screws on the left and then on the right side the ground screws it says to remove the bonding screw for subpanel but it looks like the white and ground is still attached to each other just wondering it that is correct thanks so much for any help on this

David Keith
 
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Old 04-22-12, 01:59 PM
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Do you have four wire service to the panel?
 
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Old 04-22-12, 02:03 PM
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Yes I have 200 feet of 2224 aluminum feeder
 
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Old 04-22-12, 02:08 PM
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You need to remove the bond screw (if present), and buy (If you haven't) and install a ground bar.
 
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Old 04-22-12, 02:24 PM
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] OK by ground bar I am assuming you mean the 6 foot metal stake you pound in the ground I bought 2 of em they said to be sure put two in 6 feet apart
 
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Old 04-22-12, 03:05 PM
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OK by ground bar I am assuming you mean the 6 foot metal stake
No it is a bar that goes into the panel to fasten ground wires to. From your description you may already have one. The ground bar is bonded to the panel. The neutral bar is isolated.
 
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Old 04-22-12, 03:48 PM
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OK I gotcha yes there is a neutral bar on the left and a ground bar on the right and it looks to me like there is a metal plate linking them together but the bonding screw is out also do I have to do anything different when attaching aluminum wires to lugs and or breakers? Or just do it like copper?
 
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Old 04-22-12, 04:51 PM
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You need to use anti-oxidant paste and torque to specs for the panel.
 

Last edited by ray2047; 04-22-12 at 06:30 PM.
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Old 04-22-12, 06:07 PM
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Square D uses a auxillary ground bus, purchased separately. You cannot isolate one of the busses that are factory installed to be a grounding bus.
 
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Old 04-23-12, 12:22 AM
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OK great thanks for all the info guys
 
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Old 04-25-12, 01:55 PM
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ground bar

OK I got the ground bar and the anti toxin paste but no luck on the torque screw driver or to find out how much torque is needed
 
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Old 04-25-12, 01:59 PM
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Then just use common sense to torque.
 
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Old 04-25-12, 02:21 PM
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no luck... to find out how much torque is needed
Check the labeling on the inside of the panel cover.
 
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Old 04-25-12, 02:57 PM
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OK thanks so much for the info
 
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Old 04-27-12, 04:37 PM
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subpanel ground

OK so I go through all the proper steps get the sandpaper and ant-toxin paste and open up my main panel and it's 200 amp aluminum cable coming in and guess what ? no anti paste on it nor on the other 50 amp range cable I am assuming the box has been here since the house was built in 1986 and so far it's holding up good or didn't they put paste on back then and torque up the screws? Just wondering if I went through all that for nothing
 
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Old 04-27-12, 05:56 PM
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The anti-oxidant is a good practice, but is not required by the Code.

The installer may have used a torque wrench but there is no real way to check. The value changes after the conductor adjusts to the clamping forces.
 
 

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