handhole Grounding Method

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faresos

Senior Member
I have a situation where a 480/277V service entrance cable (from transformer) going through a handhole to feed a building (main service). The service entrance cable will be spliced in the manhole and extended to the building main service. The specification indicate to provide a driven ground rod and connect to 1/0 AWG bare but it doesn't say where needs to be bond to. I believe the other end of the wire needs to be bonded to the manhole metal cover and cover frame (no other metal components in the handhole) . My questions:

1. I'm not really sure if this will provide any fault path to trip the breaker. Not sure what is the proper way to bond the handhole cover and cover frame.

2. if the cover and the frame did not come with ground connection, what is the method of bonding?

Thanks,
 

jeremy.zinkofsky

Senior Member
Location
nj
I have a situation where a 480/277V service entrance cable (from transformer) going through a handhole to feed a building (main service). The service entrance cable will be spliced in the manhole and extended to the building main service. The specification indicate to provide a driven ground rod and connect to 1/0 AWG bare but it doesn't say where needs to be bond to. I believe the other end of the wire needs to be bonded to the manhole metal cover and cover frame (no other metal components in the handhole) . My questions:

1. I'm not really sure if this will provide any fault path to trip the breaker. Not sure what is the proper way to bond the handhole cover and cover frame.

2. if the cover and the frame did not come with ground connection, what is the method of bonding?

Thanks,

You will need to establish your service ground (bond the neutral and ground). You can either do it at the utility transformer secondary or at the service disconnecting means. Choose one, and drive your ground rod there. The cable that is connected to that bond is considered the grounding electrode conductor (GEC) and will be connected to the building grounding system. This is different than the equipment grounding conductor (EGC) which is the cable that connects each panels ground bus to all exposed metal parts throughout the building.

I would advise establishing your service GEC bond at the main service disconnect. That way you will only need to pull (3) phases, (1) neutral, and (1) EGC through the handhole. That EGC, which is sized according to OCPD amperage, would bond to all metal parts in the handhole.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
You will need to establish your service ground (bond the neutral and ground). You can either do it at the utility transformer secondary or at the service disconnecting means. Choose one, and drive your ground rod there....

No you don't choose one. The NEC doesn't start till you hit the service point. 250.24 tells you to bond and earth at the service.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
I have a situation where a 480/277V service entrance cable (from transformer) going through a handhole to feed a building (main service). The service entrance cable will be spliced in the manhole and extended to the building main service. The specification indicate to provide a driven ground rod and connect to 1/0 AWG bare but it doesn't say where needs to be bond to. I believe the other end of the wire needs to be bonded to the manhole metal cover and cover frame (no other metal components in the handhole) . My questions:

1. I'm not really sure if this will provide any fault path to trip the breaker. Not sure what is the proper way to bond the handhole cover and cover frame.

2. if the cover and the frame did not come with ground connection, what is the method of bonding?

Thanks,
The spec makes no sense. You are correct it won't do anything to clear a fault. Besides almost all handhold boxes are plastic or fiberglass so what would it bond? And besides that the box is burried in the dirt, what's a ground rod going to do?
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
I have a situation where a 480/277V service entrance cable (from transformer) going through a handhole to feed a building (main service). The service entrance cable will be spliced in the manhole and extended to the building main service. The specification indicate to provide a driven ground rod and connect to 1/0 AWG bare but it doesn't say where needs to be bond to. I believe the other end of the wire needs to be bonded to the manhole metal cover and cover frame (no other metal components in the handhole) . My questions:

1. I'm not really sure if this will provide any fault path to trip the breaker. Not sure what is the proper way to bond the handhole cover and cover frame.

2. if the cover and the frame did not come with ground connection, what is the method of bonding?

Thanks,

Since you stated this is a master spec but the handhole is in the service entrance cable I would ignore the building spec and ask the Utility Company what they require and/or want. This is the path of least resistance approach. Likely case, no one else will ever look and the installation is exactly what is needed. That box and that cable don't belong to the owner and they aren't covered by the NEC. Worst case, someone tells you you have to drive a ground rod later on and you ask them to provide a detail of bonding at that time.

Not saying this is the right or wrong way, just what I would do.
 

faresos

Senior Member
The transformer, secondary conductors and the handhole are owned by the customer. This a military base and the government owns the power distribution on the base. The handhole/manhole (almost 5ft deep) is a precast with metal cover. My service entrance equipment (400A service entrance fused disconnect switch with 225A fuses) is in the building. Per NEC we need to bond the metal cover and the frame. Is there any reason why can't bond to the spliced grounded conductor 9neutral) in the handhole ( after bonding the cover and the frame and the manhole ground rod

Thanks,
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
The transformer, secondary conductors and the handhole are owned by the customer. This a military base and the government owns the power distribution on the base. The handhole/manhole (almost 5ft deep) is a precast with metal cover. My service entrance equipment (400A service entrance fused disconnect switch with 225A fuses) is in the building. Per NEC we need to bond the metal cover and the frame. Is there any reason why can't bond to the spliced grounded conductor 9neutral) in the handhole ( after bonding the cover and the frame and the manhole ground rod

Thanks,

In that case, then you need to write an RFI in my opinion. Make them tell you.
 
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