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Busbar Size

Merry Christmas
N

NewElec

Member
Location
Arkansas
Occupation
Solar Director
I have a 1200A, 3 phase, 3W bus with the following breakers in the SLD; 100A, 100A, 75A, 50A, 100A, 100A. In addition, there is a 200A ATS, 300A Meter, 300A Generator. The new addition would be a 200A breaker. According to 705.12(b), I would need to upsize the busbar. The EE states that is incorrect, but will not explain how that is possible. Can someone explain?
 
J

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
General panelboard and switchboard bussing is rated based on heat rise. There is no way to determine the ampacity just by looking at the bussing or by knowing it's dimensions.

Custom switchboards and metering equipment may be built using bus bar density (amps/square inch).
 
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