Converting main panel to sub panel

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  #1  
Old 08-02-14, 08:41 AM
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Converting main panel to sub panel

I am converting my two family home into single family. I want to change one of the two existing main panels into a sub panel. These are both newer Square D QO main panels, and the one that will become a subpanel is 100 amps. I plan to feed the subpanel with 60 amp breaker and 6/3 cable and separately connect the grounds. The panels are side by side.

Regarding the pic below:

1) should the 60amp feed to the subpanel go into the existing 100amp breaker, or is there some other way this should be fed? I see the 100amp breaker acting as a disconnect only, not as the breaker.
2) Anything special I should do for the existing feeds for the subpanel (from the abandoned meter). I would normally just wire nut and tape an abandoned cable.

Thanks.

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  #2  
Old 08-02-14, 08:52 AM
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Also:

3) The two panels each has its own earth ground. Rather than connect the ground bars between the panels, as shown on the diagram, is it OK to just clamp together the two existing earth ground cables outside of the box (the cables that go to the ground rods)?
 
  #3  
Old 08-02-14, 04:55 PM
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1) should the 60amp feed to the subpanel go into the existing 100amp breaker
Yes.

2) Anything special I should do for the existing feeds for the subpanel (from the abandoned meter). I would normally just wire nut and tape an abandoned cable.
I would remove them and close any knockouts left open.

3) The two panels each has its own earth ground. Rather than connect the ground bars between the panels, as shown on the diagram, is it OK to just clamp together the two existing earth ground cables outside of the box (the cables that go to the ground rods)?
I would remove the GEC from the subpanel to the ground rod and use the fourth wire (ground wire) between the two panels to connect the ground bar in the second panel to the grounded neutral bus in the first panel.

In your first panel diagram you show the GEC going to ground rods and/or water pipe. The water pipe connection is not an option and is mandatory in addition to the ground rod/rods. The water pipe connection is required when the water service line entering the house is metallic for at least 10 feet before entering the house; it must be connected within 5 feet of where the water service enters the house. If you have a non-metallic water service line entering the house and metallic water lines in the house, the water lines in the house must be bonded to the grounded neutral bus.
 
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Old 08-02-14, 05:25 PM
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For what you are doing this would be the more correct diagram:

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The one you chose was for one not in the same structure.
 
  #5  
Old 08-03-14, 09:36 AM
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Thanks. Main panel is grounded both to a ground rod, and to an appropriate water line.

Regarding #2, my question was, once I remove the old main feeds, what is the correct way to cap these larger Al cables. Or just tape them and forget about them. They will still connect to the meter box, although now there will be no meter.
 
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Old 08-03-14, 05:42 PM
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Regarding #2, my question was, once I remove the old main feeds, what is the correct way to cap these larger Al cables. Or just tape them and forget about them. They will still connect to the meter box, although now there will be no meter.
Why do you want to keep the old cable? I'd just remove it and be done with it.
 
  #7  
Old 08-03-14, 05:47 PM
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The old cable should be removed from the meter socket and the panel.

Are you sure 60 amps is enough?
 
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