Sub-Panel Ground

[gsurace]

Simple question, is it allowed by code to use rigid conduit as the ground to a sub-panel if the existing feeder only has 3 wires? The sub-panel is feed with 200 amps. Just looking to see if it is NEC acceptable, not exactly how it "should" be done.

 

[gsurace]

Let me just clarify my situation. I have an existing 200 amp sub-panel where the feeders are in 2" rigid conduit and there is a #6 ground wire pulled with the feeders. Unless I am unaware of some exception to use #6 I am looking to see if I could utilize the rigid conduit for the ground conductor.

 

[dkidd]

A #6 copper is good for 200 amps.

 

[gsurace]

If that is the case, then this is yet another situation were I've always gone over and above (using #4 for a 200 amp sub-feed ground) and was unaware exactly what the actual minimum requirement is. Can you point me to an article in the NEC where this is found for my own education.

 

[dkidd]

If that is the case, then this is yet another situation were I've always gone over and above (using #4 for a 200 amp sub-feed ground) and was unaware exactly what the actual minimum requirement is. Can you point me to an article in the NEC where this is found for my own education.

Table 250.122 Minimum Size Equipment Grounding
Conductors for Grounding Raceway and Equipment

 

[gsurace]

Got it. Thanks you.

My issue was always using 250.66 all the time to size the ground wires which does not apply to this situation. With that said, it appears my RMC could be used as the equipment grounding conductor per 250.118(2) if ever needed, correct?

 

[dkidd]

Got it. Thanks you.

My issue was always using 250.66 all the time to size the ground wires which does not apply to this situation. With that said, it appears my RMC could be used as the equipment grounding conductor per 250.118(2) if ever needed, correct?

Yes. However, if for example, the ground wire was only #8, you would have to remove it, since it wouldn't be compliant, and only use the conduit.

Left the outrage commence.