ground question

[don_resqcapt19]

What is the size of the OCPD on the line side of the parallel 600's? In one place you say 800 amps, but in your last post you say you need a 3/0 EGC which implies a 1200 amp OCPD. If the OCPD is 800 amps, then a 1/0 is fine.

 

[duluthelectrical]

1200 amp swithgear, 800 disco so 3/0 is still correct, should have stated that sorry

 

[don_resqcapt19]

If the OCPD is 800 amps, the equipment grounding conductor is 1/0 copper or 3/0 aluminum. Are you using aluminum for the EGC and copper for the phase conductors?

 

[duluthelectrical]

Copper phase conductors and copper ground

 

[don_resqcapt19]

Copper phase conductors and copper ground

If the OCPD is 800 amps then the code minimum size EGC is 1/0, not 3/0.

 

[quogueelectric]

Just bond the conductor to the pipe at both ends and there is no choke effect.

In Crossman's scenario the pipe enclosing the EGC wire conductor would be physically connected to the equipment and the conductor is too, the bonding is already done.

Roger

I was going to add that in my next post but didnt to avoid further clubbing thanks I wasnt 110% sure.

 

[quogueelectric]

I was going to add that in my next post but didnt to avoid further clubbing thanks I wasnt 110% sure.

Funny story about working with my father who has been an electrician since ben franklin. Working on my mothers house service we were arguing over sleving the ground I wanted pvc he wanted emt so I let him win until it got knocked down by the inspector. It killed him to admit a mistake but I had to let him do it his way at eighty something he still has a lot of fight left in him. He had a low 3 digit license number like #3 too funny mine is like 30,000. Sometimes you have to let the seniors win out of respect.

 

[duluthelectrical]

mdp is 1200 amps- the switchgear, then we go to the disco which is 800 amps, I sized the 3/0 off the 1200 mdp

 

[don_resqcapt19]

mdp is 1200 amps- the switchgear, then we go to the disco which is 800 amps, I sized the 3/0 off the 1200 mdp

How do you get to the 800 amp disconnect from the 1200 switchgear? If you ran the parallel 600's, then they are way undersized if they are protected at 1200 amps unless you meet the requirements of one of the tap rules. Are the runs in question fed from the switchgear or from the 800 amp disconnect? Is the disconnect a circuit breaker or have fuses? Or is it a nonfused disconnect?