Potential11

From what I understand they are required on separate derived systems, a service, and where there are concentric and eccentric ko's. Any help?

icefalkon

Hi there,

Well yes you're correct. You need them at a service and at a SDS if you use the provided KO's. However, if you make your own holes...you can use a bonding locknut instead of a MIGB (Malleable Iron Grounding Bushing). Other instances where you might find it necessary to use a MIGB include but are not limited to lightning protection applications and some UPS system installations.

Potential11

Will a main bonding jumper be sufficient in a PV system or will Ground Bushing be required where AC CB are installed?

Shockdoc

Over 250 volts to ground, Centerfrugal knock outs to name a couple.

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All these liberal laws has turned me into a right wingnut..

Dennis Alwon

Once you are past the service no bonding bushings are required unless you have a voltage over 250v to ground and then not always. art. 250.97

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480sparky

Centerfrugal? The middle of being stingy?

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In winter, why do we try to keep the house as warm as it was in summer when we complained about the heat?

icefalkon

LOL

I think he meant concentric and eccentric...which the OP mentioned.

Here's another application where it's necessary...

Ground Riser in a building...IF run in ferrous metal conduit. EMT, GAL, IMC...if it's in FRE or PVC it is not necessary. Problem with that is...many of the large engineering firms are now speccing a 500MCM ground riser...which is ridiculous. UL did a study that over sizing the wire to 500's from 3/0 does nothing. A major problem we have with high rise construction is that the engineer will spec out the 500MCM in a 2" conduit. There is no UL listed MIGB that can handle a wire that size. Besides...BENDING the 500 to get into the split lug would be a job for Superman!