MCC Ground bus sizes... When do you go up?
MCC Ground bus sizes... When do you go up?
(OP)
I always specify a 300A Ground bus for MCCs. MCC manufacturers offer higher bus ratings as an option, ie 600A.
I'm just curious, when will this be required? How do you properly size the ground bus bar?
I'm just curious, when will this be required? How do you properly size the ground bus bar?






RE: MCC Ground bus sizes... When do you go up?
"Such requirements illustrate a common misunderstanding about the function of a ground bus in switchgear.
In installations subject to the National Electrical Code (NEC) (ANSI/NFPA 70), the equipment ground conductor is not intended to carry normal load current. The ground bus is intended to carry current only when some sort of fault occurs that involves ground."
See: "Ground Bus Ratings"
http
Also see:
"Rating of Ground Bus in Metal-Enclosed Switchgear"
http:
RE: MCC Ground bus sizes... When do you go up?
"While a ground bus, like any conductor,will carry a certain amount of current continuously without damage, just how much and under what circumstances is not defined. Therefore, specifying a continuous current rating for ground bus has little or no meaning and should be avoided."
Source: Rating of Ground Bus in Metal-Enclosed Switchgear
Yeah that is what I figured... and I am wondering why most LV MCC manufacturers provide Ground bus current ratings of 300A, 500A, etc... with the option to upsize.
RE: MCC Ground bus sizes... When do you go up?
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