Grounding existing subpanl in separate building.

[Al21]

I replaced 2 100 amp meter mains with a single class 320 meter main. There is 1 1/4 ridged conduit from the main feeding a subpanel in a house 100' away. There are 3 wires in the conduit. The local inspector who inspected the new meter main said I needed to run a new equipment ground from the new meter main to the subpanel at the house. This is not possible. What code section allows me to use a ground rod to ground the subpanel at the house?

 

[George Stolz]

I don't see why it can't be done if the feeder is in conduit - otherwise, see 2008 250.32(B) exception.

 

[hurk27]

If this ridge conduit is metal then why can't it be used as the EGC as allowed in 250.118?

 

[infinity]

Does you jurisdiction require you to upgrade an existing feeder on a service upgrade?

 

[suemarkp]

What code section allows me to use a ground rod to ground the subpanel at the house?

None. The fault ground must be a conductor -- grounded neutral or separate equipment ground. You can't use the earth as a fault conductor. Since you're feeding a detached building with a feeder, that building requires a ground electrode too. Your issue is the feeder -- current rules require all feeders to have a separate equipment ground (can't use a neutral as a ground like on a service anymore). However, the NEC exempts EXISTING feeders from that rule. If you're not pulling new conductors, you should be able to use that exemption. Or, if the rigid conduit is metal, that can be your 4th "wire" if it is well connected and complete to the remote building.

In theory, you should be able to fit 2-2-4-6 THWN copper in that conduit. May be tough to pull though.

 

[Al21]

Thanks for all the responses. It was a new inspector, and he said the integrity of the ridged conduit (underground) could not be verified. I will talk to him about 250.32 B as an exception.