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Overcurrent sizing for NM

TimNY

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Joined
Jan 13, 2010
Messages
1,133
Location
Charleston, SC
Given a subpanel fed with 6-3 NM, what is the proper overcurrent device size?

Code says ampacity of NM to be based on 60C.

60C says 55A for #6.

Inspector says must be protected at 50A.

Contractor asks me to look.

Seems to me it is allowed to be protected at 60A per E3605.5.2?

Thanks,

Tim
 
TimNY said:
Given a subpanel fed with 6-3 NM, what is the proper overcurrent device size?Code says ampacity of NM to be based on 60C.

60C says 55A for #6.

Inspector says must be protected at 50A.

Contractor asks me to look.

Seems to me it is allowed to be protected at 60A per E3605.5.2?

Thanks,

Tim
I agree with you Tim, the next size up rule is permitted to be used in this situation since 55 amps is not a standard circuit breaker size.

Keep in mind that the calculated load of the panel could not exceed 55 amps though.

Chris
 
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