Grounding all metal parts

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goldstar

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
This is classic. We all find things that make us shake our heads at times when we see them. This is one of those times. I had to remove sheathing from an outside wall to install wiring for coach lights and recessed lights for a new porch. Whoever did this had good intentions (in their own mind) but obviously did the wrong thing. Also, I didn't show this photo but, in the wall bay adjacent to this one is a 2-gang metal gem switch box. The machine screws for the clamps holding the NMC cables have nuts on the back holding the ground wires for both cables. Luckily I don't have to do any work in the rest of this house (at least not yet :rant:). AND, on top of it all, if you could have seen the single and two gang switch plates on the finished side of the wall the one with the blue plastic box is 1/4" lower that the 2-gang box. I don't think there was pride in this installation nor do I want to believe it was done by an electrician. :happyno:

 
It never ceases to amaze me the ways an installation can be done wrong.
 
iwire said:
I don't think that connection complies with 250.8. :D
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Making me wonder.

When was it common practice to take the grounds out of the metal box and attach it to the exterior if the box with a fork terminal.

In this case I think there was an existing metal box that did that so they followed suit with the plastic box then had no place to land it

The other box had no location for landing so it was nut and bolted.
 
ritelec said:
When was it common practice to take the grounds out of the metal box and attach it to the exterior if the box with a fork terminal.
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In my area never, but what was done here was wrapping the EGC around the cable and clamping down on it with a metal NM connector. :(
 
ritelec said:
Making me wonder.

When was it common practice to take the grounds out of the metal box and attach it to the exterior if the box with a fork terminal.

In this case I think there was an existing metal box that did that so they followed suit with the plastic box then had no place to land it

The other box had no location for landing so it was nut and bolted.
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Not sure about that. There were holes in the backs of the metal gem boxes where ground screws usually would be installed. However, I found that they were not tapped and made ready for #10/32 ground screws. Did that mean, way back when, that you didn't have to carry a tap and tap out the hole ?
 
iwire said:
In my area never, but what was done here was wrapping the EGC around the cable and clamping down on it with a metal NM connector. :(
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At least in that case the box was grounded. Maybe not properly but it was grounded. FWIW, I've come across many installations in my area where metal boxes were used and the grounds landed on the backs of the metal gems. Not sure if that was ever a correct method but it certainly was popular.
 
goldstar said:
FWIW, I've come across many installations in my area where metal boxes were used and the grounds landed on the backs of the metal gems. Not sure if that was ever a correct method but it certainly was popular.
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FWIU, it was legal up until the code changed in the late 1960s or so and started requiring that the egc be terminated and/or spliced within the box.
 
goldstar said:
Not sure about that. There were holes in the backs of the metal gem boxes where ground screws usually would be installed. However, I found that they were not tapped and made ready for #10/32 ground screws. Did that mean, way back when, that you didn't have to carry a tap and tap out the hole ?
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I have seen those holes you're talking about in the back of the gem boxes be used for mounting- box mounted with wood screws in 2x4 run between studs. Other times in old installations have seen the egc actually in box but wrapped around the screw of un unused bottom cable clamp- which would be legal if the clamp was removed- the screw cannot serve any other purpose.
 
user 100 said:
Other times in old installations have seen the egc actually in box but wrapped around the screw of un unused bottom cable clamp- which would be legal if the clamp was removed- the screw cannot serve any other purpose.
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Understood. Wouldn't the screw also have to be identified for the inrended use (i.e. green)?
 
ritelec said:
When was it common practice to take the grounds out of the metal box and attach it to the exterior if the box with a fork terminal.
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I've never seen it done that way, either.

Apprenticed in '68 under the '65 NEC and we ignored the metal boxes, but landed on the device screw. By '71, was also bonding to the metal enclosure (different jurisdiction, more rigorous.)
 
jumper said:
I think that a screw type main bonding jumper has to green also.
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Yes- 250.28(B).

But as far as egc screw in device box, the answer (apart from the egc terminal on the device itself) is no.

jumper said:
You lost me.:?

I am referring to a screw that is commonly used to bond an enclosure to the grounded conductor at the first disconnect.
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Look just to the right of center in op pic.:happyyes:
 
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