Hand Hole W/Metal Cover

Ajimenez

Member
Location
florida
Occupation
Project coordinator
Good morning ,
I have a hand hole with a metal traffic cover where the service feeders are splice with Polaris , the inspector is asking me to bonding the cover with the service ground , so in other words he want me to run back from the service ( first point ) to the hand hole a ground wire to bonding the metal cover , this is a correct method to bonding or grounding with ground rod ?
https://www.dropbox.com/sh/hvg9xtfis6y08z8/AACCA2sM4en7pnJwSnTftO0pa?dl=0
 

tom baker

First Chief Moderator
Staff member
Not clear, is this a service or feeders, you mention "service feeder", and "service ground", services don't have a ground, ground is not the correct term.
 

Eddie702

Senior Member
I think the inspector is nuts.

I don't think it needs to be bonded. If it did it could be connected to the neutral (grounded service conductor) as it is on the line side of the service opd

I have never had an inspector ask for that. I would think the box/cover mfg would have to provide a means of attachment if that were true
 

tom baker

First Chief Moderator
Staff member
Sorry, I couldn't open your drawing earlier. Yes you will need to bond the cover with a bonding jumper, it may be easier to go the service disconnect. You mention a ground rod and make sure you understand that a ground rod will not prevent an electric shock if the cover is energized, do the math, 120V, 25 ohms resistance results in about 4 amps, more than enough for a fatal shock.
The size of the bonding jumper is based from Table 250.66. I've not run into this type of bonding before but you should be able to use the neutral to do the bonding in the handhole.
 

tom baker

First Chief Moderator
Staff member
I think the inspector is nuts.

I don't think it needs to be bonded. If it did it could be connected to the neutral (grounded service conductor) as it is on the line side of the service opd

I have never had an inspector ask for that. I would think the box/cover mfg would have to provide a means of attachment if that were true
 

tom baker

First Chief Moderator
Staff member
ConEd didn't think the handhole needed to be bonder either....

Handholes are required to be bonded, all the ones I have installed have a strap to the lid and a bonding stud
 

PaulMmn

Senior Member
Location
Union, KY, USA
ConEd didn't think the handhole needed to be bonder either....

Handholes are required to be bonded, all the ones I have installed have a strap to the lid and a bonding stud
Was the ConEd a handhole, or one of those steel plates used to cover an excavation so cars can drive over them?
 

texie

Senior Member
I think the inspector is nuts.

I don't think it needs to be bonded. If it did it could be connected to the neutral (grounded service conductor) as it is on the line side of the service opd

I have never had an inspector ask for that. I would think the box/cover mfg would have to provide a means of attachment if that were true
No, the inspector is correct. See 314.30(D). This has been in the code for a long time. There have been many electrocutions from energized metallic hand hole covers over the years.
 

tom baker

First Chief Moderator
Staff member
Was the ConEd a handhole, or one of those steel plates used to cover an excavation so cars can drive over them?
ConEd handhole. This electrocution made all the utilities sit up and take notice that they had stray voltage issues.
Even though they are not subject to the NEC, the danger is the same.
 
ConEd handhole. This electrocution made all the utilities sit up and take notice that they had stray voltage issues.
Even though they are not subject to the NEC, the danger is the same.
I would be curious to know more details about that incident. How did the cover become energized? Was it neutral current? Seems unlikely that the cover would be energized with line voltage. Also seems like just bonding the frame the cover mates to would be adequate.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
I would be curious to know more details about that incident. How did the cover become energized? Was it neutral current? Seems unlikely that the cover would be energized with line voltage. Also seems like just bonding the frame the cover mates to would be adequate.
It could easily be line voltage, the cover, just like ground rods, can be high resistance connections. I had a gas station I wired many years ago shock people when they opened the door (metal door, frame and handle set in block) I was getting 120 volts to ground. Checked everything I did, could not find the problem. Turned off the power to the pump panel that the petroleum company installed, voltage disappeared. Found wire straight off a 20 amp breaker stripped and laying against the wire way outside. Their “electrician” used a pvc nipple between the wire way and the panel, but no grounds. Even with 100’s of feet of rigid buried in the ground, the resistance was still not low enough to trip the breaker. It truly was a wonder somebody didn’t start a fire since the pumps were live too!
 
It could easily be line voltage, the cover, just like ground rods, can be high resistance connections. I had a gas station I wired many years ago shock people when they opened the door (metal door, frame and handle set in block) I was getting 120 volts to ground. Checked everything I did, could not find the problem. Turned off the power to the pump panel that the petroleum company installed, voltage disappeared. Found wire straight off a 20 amp breaker stripped and laying against the wire way outside. Their “electrician” used a pvc nipple between the wire way and the panel, but no grounds. Even with 100’s of feet of rigid buried in the ground, the resistance was still not low enough to trip the breaker. It truly was a wonder somebody didn’t start a fire since the pumps were live too!
I am thinking of a typical utility/transformer vault that is made of concrete, except for the cover an the cover ring. The cover and ring are presumably many feet away from the conductors. I guess maybe there are electrical vaults that are wired so messy (like telco and cable company style) that there are conductors in close proximity and/or sweeping wildly into the access hole area? Maybe I just havnt been in enough vaults to understand and I am blissfully enjoying my naivety 😇
 

hillbilly1

Senior Member
Location
Atlanta,Ga
I am thinking of a typical utility/transformer vault that is made of concrete, except for the cover an the cover ring. The cover and ring are presumably many feet away from the conductors. I guess maybe there are electrical vaults that are wired so messy (like telco and cable company style) that there are conductors in close proximity and/or sweeping wildly into the access hole area? Maybe I just havnt been in enough vaults to understand and I am blissfully enjoying my naivety 😇
The fault can actually conduct through the concrete vault to the cover, even though the concrete is in contact with the soil. The soil at the gas station was rocky and a poor conductor. Could have been the same at the accident site. I drove two ground rods through almost solid rock there! LOL!
 
The fault can actually conduct through the concrete vault to the cover, even though the concrete is in contact with the soil. The soil at the gas station was rocky and a poor conductor. Could have been the same at the accident site. I drove two ground rods through almost solid rock there! LOL!
It seems like that would be more of a step potential issue and thus the most dangerous parts would be the ones that are LESS conductive, so not the cover. Like I said, I would like to know exactly what happened in the Con Edison case.
 

tom baker

First Chief Moderator
Staff member
The accident was in November in NYC. Roads had been salted. Cover was energized by a 120/208 in a handhole by curb. I think Jodie was walking her dog, dog got shocked, then she got shocked, fell down and reached for curb that had a metal strip in it. Someone else came by to to help, got shocked, policeman said if any one touches here I will arrest them. She died and a huge lawsuit, a foundation was set up. Lots of information available via google.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
The accident was in November in NYC. Roads had been salted. Cover was energized by a 120/208 in a handhole by curb. I think Jodie was walking her dog, dog got shocked, then she got shocked, fell down and reached for curb that had a metal strip in it. Someone else came by to to help, got shocked, policeman said if any one touches here I will arrest them. She died and a huge lawsuit, a foundation was set up. Lots of information available via google.
Unfortunate and sad, I investigated a case where at a big box home improvement store an employee got shocked from a pipe threading machine. The ground pin was missing from the cord, and the foot pedal had an internal short. He touched the grounded racking and completed the path. The doctors said he was lucky he was overweight or it would have killed him. Still messed him up pretty bad. On another store, they had hit a conduit drop with a forklift and broke it. They were using the emt as the egc so it energized the racking, luckily nobody was hurt other than mild shocks.
 
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