Unprofessional grounding technique

Status
Not open for further replies.
N

Not My Fault

Member
Location
Moundsville, WV
My brother sent his electrician to an affiliated educational facility to install a new 120 V AC light fixture. The electrician noticed that whoever previously installed several metallic junction boxes terminated the ground conductor under a cable clamp screw on the outside of each junction box. The electrician also noted that the cable clamps are snap in types which he has rarely encountered, but I don't think that is relevant.

Surely this installation must be a violation of the NEC; however, I can't find the section or sections that definitively prohibit such a wiring technique. What sections do you think would address this situation?
 
Not My Fault said:
My brother sent his electrician to an affiliated educational facility to install a new 120 V AC light fixture. The electrician noticed that whoever previously installed several metallic junction boxes terminated the ground conductor under a cable clamp screw on the outside of each junction box. The electrician also noted that the cable clamps are snap in types which he has rarely encountered, but I don't think that is relevant.

Surely this installation must be a violation of the NEC; however, I can't find the section or sections that definitively prohibit such a wiring technique. What sections do you think would address this situation?
Click to expand...
The definition of "approved" would suffice. (acceptable to the authority having jurisdiction). Most metal boxes have a threaded spot for a ground screw.
 
Not My Fault said:
My brother sent his electrician to an affiliated educational facility to install a new 120 V AC light fixture. The electrician noticed that whoever previously installed several metallic junction boxes terminated the ground conductor under a cable clamp screw on the outside of each junction box. The electrician also noted that the cable clamps are snap in types which he has rarely encountered, but I don't think that is relevant.

Surely this installation must be a violation of the NEC; however, I can't find the section or sections that definitively prohibit such a wiring technique. What sections do you think would address this situation?
Click to expand...


I've seen this before, pain in the neck to ground a new cable. Seen it done at 60 unit apartment complex.
 
That is so old-school (1960's)

That is so old-school (1960's)

Not My Fault said:
My brother sent his electrician to an affiliated educational facility to install a new 120 V AC light fixture. The electrician noticed that whoever previously installed several metallic junction boxes terminated the ground conductor under a cable clamp screw on the outside of each junction box. The electrician also noted that the cable clamps are snap in types which he has rarely encountered, but I don't think that is relevant.

Surely this installation must be a violation of the NEC; however, I can't find the section or sections that definitively prohibit such a wiring technique. What sections do you think would address this situation?
Click to expand...

That was done in the 60's when there were no tapped grounding location in boxes.
 
Not My Fault said:
...

Surely this installation must be a violation of the NEC; however, I can't find the section or sections that definitively prohibit such a wiring technique. What sections do you think would address this situation?
Click to expand...

He is bonding the clamp and not the box. The connection to the box must be one of the types in 250.8. A machine screw into the box is ok. A machine screw into a fitting not listed for grounding is not.

EGCs shall be protected. 250.120(C)

The terminal for the connection of the equipment grounding conductor shall be identified by one of 250.124(1-3). Usually in retrofits a pressure connector as in 250.124(3) is used.
 
Terminal ID

Terminal ID

starbolin said:
He is bonding the clamp and not the box. The connection to the box must be one of the types in 250.8. A machine screw into the box is ok. A machine screw into a fitting not listed for grounding is not.

EGCs shall be protected. 250.120(C)

The terminal for the connection of the equipment grounding conductor shall be identified by one of 250.124(1-3). Usually in retrofits a pressure connector as in 250.124(3) is used.
Click to expand...

I suspect that you meant to cite 250.126 rather than 250.124?
 
Not My Fault said:
What threw me off in this section was the inclusion of "equipment listed for grounding" or "a listed grounding device." This made me wonder if the cable clamp might qualify as either of these items.
Click to expand...

IMO, based on what I see in the UL White Book, No.
 
Status
Not open for further replies.
Top