sub panel grounding

jprince

Hi guys
Quick question. I have seen a sub panel that is connected to the panel with metal conduit also have a ground wire run and bonded to the sub-panel. everything else is bonded at the main neutral and ground and panel. It is my understanding that you need not to run a ground wire if the sub panel is connected to the main panel by metal conduit. The ground wire he ran just came out of the conduit and was screwed directly to sub panel cabinet. Is this ok

thanks Jrff

RenoDon

Most sub-panels need to have an isolated neutral bus bar and a grounding
bar. Check local codes. The reason why is to be certain no current will flow when a ground wire is disconnected for any reason. You should install
a ground bar attatched directly to the panel box and seperate the grounds from the neutrals. You do not really need any additional grounding
if connectors are not insulated and are tight. An extra ground wire will not hurt anything,
its just not required. Yes thats OK.

220/221

Yes.

Generally we install a ground bus to accept the branch circuit grounds, but there is nothing saying that you can't just run the ground right to the can.