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Main Switchboard and Main Disconnect

A

Aistobasbistoc9

Member
Location
Texas
Occupation
Engineer
There is a 1600A main switchboard that was once rated at 1600A with main at 1600A as well. At some point, services split and they reused the 1600A main switchboard, but rerouted 800A feeders with 800A disconnect over to the switchboard (disconnect before switchboard). Is this allowable per NEC if they kept the 1600A main in the switchboard? As long as what is on the switchboard does not exceed 800A, will the 800A disconnect before the switchboard suffice? If not, could the 1600A main that was in the switchboard simply be updated to an 800A main and then we could call it good?

Please let me know what NEC references would allow or disallow either scenario.

Thank you!
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
With 800 amp protection ahead of the switchboard the 1600 amp main is simply a disconnect means and the rating is irrelevant
408.36 states the buss has to be protected at it's rating by an integral OCP means or by a remote OCP device.
 
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