I have a power pedestal - strut framed rack of 5 disconnects, fed through an auxillary gutter by way of tapped conductors coming from a disconnect inside of a building about 50ft away. This pedestal's strut rack is embedded in the concrete and there is a Ufer ground provided at the base of the rack. My question: In the conduit feeding this pedestal, I want to leave the EGC out, just pulling in the three phases and neutral. Can't I do this because of my use of the Ufer ground at the pedestal? My neutral is not bonded anywhere on the pedestal and is bonded at the disconnect feeding it. That disconnect is fed from the secondary of an transformer.
EGC to remote power pedestal
- Thread starter jimioy
- Start date
- Status
- Location
- Illinois
- Occupation
- retired electrician
What type of conduit is being used? Is the pedestal a stand alone installation? Is it outside or inside of a building?
Don
Don
- Location
- New Jersey
- Occupation
- Journeyman Electrician
hillbilly said:
Why? If this is a separate structure RNC could be used and the neutral could be bonded at the separate structure. Of course this would have to meet all of the restrictions of 250.32(B).
Thanks guys – I think I have it now. 250.32.B.1 makes it clear that my branch circuit out to the pedestal must have an EGC, since it is a branch circuit feeding a seperate structure. I’ll pull a ground over there because I have PVC in the middle of my RMC conduit run – 250.118. 250.32.B.1, last sentence, tells me not to bond my neutral. Then I’ll tie the Ufer ground to the EGC on the ground bus. Again, thanks!
jtester
Senior Member
- Location
- Las Cruces N.M.
jimioy
From the description in your original post, you don't have a branch circuit, you have a feeder. In general, branch circuits don't land on OCPD's, particularly 5 of them. You may not need to run an EGC, but you do need to be sure you have an effective fault clearing path. Eliminating the EGC will require the neutral to carry the fault current.
Jim T
From the description in your original post, you don't have a branch circuit, you have a feeder. In general, branch circuits don't land on OCPD's, particularly 5 of them. You may not need to run an EGC, but you do need to be sure you have an effective fault clearing path. Eliminating the EGC will require the neutral to carry the fault current.
Jim T
Jim - I'm still confused. This pedestal sits outside. The disconnect that feeds it is inside a building about 50ft away. This disconnect is fed from the secondary of an transformer (which has it's chasis and XO bonded to a Ufer ground and the ground is carried on to the downstream disconnect) and has it's neutral and grounds bonded. The conducters are then run out to this pedestal, tapped to feed 5 unfused disconnects, which have Canon plugs on the load side. The Canon plugs are for 3 phase portable HVAC units that have input OCPDs. I don't know if you're familiar with Military Canon plugs - they have 4 ground wires. These are landed in the disconnects on a ground bus and the neutral is landed on an isolated bus. The neutral is not extended to the HVAC units.
- Location
- Illinois
- Occupation
- retired electrician
Jim,
You must have a fault clearing path for the circuits to the HVAC units. You must either pull an EGC to the pedestal (you can leave out the grounded conductor is it is not needed for the equipment), or you pull the neutral and bond it to the grounding electrode conductor at the pedestal and extend your EGCs from that point.
Don
You must have a fault clearing path for the circuits to the HVAC units. You must either pull an EGC to the pedestal (you can leave out the grounded conductor is it is not needed for the equipment), or you pull the neutral and bond it to the grounding electrode conductor at the pedestal and extend your EGCs from that point.
Don
- Status