sub panel ques?

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wireman1

Senior Member
in a dwelling can install two 2oo amp 20 ciruit sub panels off the main which is a 30 circuit 200amp panel? since you did not exceed the over current protection of the main panel breaker which is 200 amps
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
The number and ratings of subpanels is not relevant. You can install ten 400 amp subpanels and feed them all from a 200 amp main panel. What matters is the "calculated load" you supply from the panels. You cannot load any panel beyond its rating, nor can the total load on all the subpanels exceed the rating of the main panel.
 

charlie b

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Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
And the feeders are sized to the load also,right?
Yea, that is important too. I have one client that insists that the feeder to any panel be sized for the full ampere rating of the panel, even if the intended (or calculated) load is lower. That is not an NEC requirement, but is within their published standards.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
Yea, that is important too. I have one client that insists that the feeder to any panel be sized for the full ampere rating of the panel, even if the intended (or calculated) load is lower. That is not an NEC requirement, but is within their published standards.

It's always been my thought that if you were putting in a 200 amp panel and the main can handle the load, why not? Same amount of work just bigger conduit and wire.
 

kwired

Electron manager
Location
NE Nebraska
It's always been my thought that if you were putting in a 200 amp panel and the main can handle the load, why not? Same amount of work just bigger conduit and wire.

Then you trim a few strands at the 60 amp feeder breaker so the conductor will fit in the lug:cool:
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
Yea, that is important too. I have one client that insists that the feeder to any panel be sized for the full ampere rating of the panel, even if the intended (or calculated) load is lower. That is not an NEC requirement, but is within their published standards.

Are you saying it's within the panel's published standards that even if a feeder is properly protected with OCPD upstream it has to be sized to the panels full amp rating or are you talking about our client's standards?
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Are you saying it's within the panel's published standards that even if a feeder is properly protected with OCPD upstream it has to be sized to the panels full amp rating or are you talking about our client's standards?
That was stated in my client's standards.
 
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