Ground Bushing for 750 Kcmil Cu?

[scotteng]

Does anyone make a bushing for a 750 Kcmil ground riser? Have a project in CA where a bare ground needs to be routed via a seismic joint and the current thought is to route via metallic sleeve, but can't find any way to bond both ends. FYI - can't use PVC due to above ceiling being uses as a return air plenum.

 

[GoldDigger]

If you use non magnetic pipe (aluminum or stainless) to sleeve a GEC you do not have to bond both ends since there will not be a strong choke effect.

 

[scotteng]

If you use non magnetic pipe (aluminum or stainless) to sleeve a GEC you do not have to bond both ends since there will not be a strong choke effect.

Interesting. Is there a code section I can reference where this is stated as such?

 

[ActionDave]

Interesting. Is there a code section I can reference where this is stated as such?

250.64 (E) starts right off with the words "Ferrous metal enclosures"

 

[ron]

Maybe you put ground / bonding bushing on each end of the raceway and just jump from the 750 to the bushing with a smaller wire.

 

[scotteng]

250.64 (E) starts right off with the words "Ferrous metal enclosures"

Thanks Dave.

 

[don_resqcapt19]

Maybe you put ground / bonding bushing on each end of the raceway and just jump from the 750 to the bushing with a smaller wire.

If 250.64(E) applies, then 250.64(E)(3) requires the bonding jumper to be the same size or larger than the enclosed grounded electrode conductor.

That being said, is the conductor in this thread really a GEC? If not, then 250.64 does not apply.

 

[MasterTheNEC]

If 250.64(E) applies, then 250.64(E)(3) requires the bonding jumper to be the same size or larger than the enclosed grounded electrode conductor.

That being said, is the conductor in this thread really a GEC? If not, then 250.64 does not apply.

A point that I too often find people seem to forget.....and apply 250.64 broadly....Whats that Charlie Rule again....

 

[donaldelectrician]

Does anyone make a bushing for a 750 Kcmil ground riser? Have a project in CA where a bare ground needs to be routed via a seismic joint and the current thought is to route via metallic sleeve, but can't find any way to bond both ends. FYI - can't use PVC due to above ceiling being uses as a return air plenum.

A Question ? What in the world requires a 750 kcm as and EGC ?





Don

 

[MasterTheNEC]

A Question ? What in the world requires a 750 kcm as and EGC ?





Don

A 4000A service with an AL EGC...or a 5000A service when the local supplier only has 750 kcmil CU available....:jawdrop:

Or.....maybe an Engineer who doesn't have a code book...but has a red stamp available.

 

[don_resqcapt19]

A Question ? What in the world requires a 750 kcm as and EGC ?





Don

This is very likely a communications grounding conductor required by the design specs.

 

[scotteng]

This is very likely a communications grounding conductor required by the design specs.

Bingo

 

[infinity]

Can you use something like this and forget the grounding bushing? We use these all of the time.

 

[pjholguin]

Do you have a part number?

Can you use something like this and forget the grounding bushing? We use these all of the time.

 

[infinity]

I'll see if I can find it.