Ground Bar vs Individual Lugs

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xguard

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Is there a benefit, or a requirement, to use a grounding bar instead of installing individual grounding lugs on a disconnect or panel? I'm including a photo, hopefully it's not too blurry to clarify what I'm talking about.
 

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Using individual lugs relies on the conductivity of the steel box, and the connection between the lug and the box.
The dissimilar metals (aluminum or copper lug, steel box) is vulnerable to corrosion, the bolted joint is vulnerable to loosening, and there might be a poor connection from Day One if the paint isn't disturbed.
If there's a very high fault current, the thin steel might not have adequate cross-sectional area or conductivity.

Using a ground bar, or a multiple lug, the wires are clamped to the very same piece of metal, eliminating several electrical connections and mechanically-fastened joints.

I'm probably overthinking it and seeing potential problems that seldom actually occur.
 
There is no code issue with the EGC connections in the photo unless they haven't properly cleaned the metal surface.
 
infinity said:
There is no code issue with the EGC connections in the photo unless they haven't properly cleaned the metal surface.
Click to expand...

It may be up to code, but how are those little sheet metal screws going to hold under conductor movement from a bolted fault? Is it not an issue, or are they not expected to?
 
So what about using what the panel lists for grounding lugs and bars? Is bolting your own individual lug in a panel code compliant when its not listed in the panel instructions?

and it appears in the picture, he had to make his own bolt hole pattern for those lugs.
 
mopowr steve said:
So what about using what the panel lists for grounding lugs and bars? Is bolting your own individual lug in a panel code compliant when its not listed in the panel instructions?

and it appears in the picture, he had to make his own bolt hole pattern for those lugs.
Click to expand...

If the instructions don't say you can't do it, I do think it's a clear violation.
 
In the 2008 NEC, 408.40 states "...Where the panelboard is used with nonmetallic raceway or cable or where separate equipment grounding conductors are provided, a terminal bar for the equipment grounding conductors shall be secured inside the cabinet. ..." This does not indicate that individual lugs are acceptable for multiple equipment grounds. As a former NYC inspector, this would have been grounds for a violation, as well as the self tapping screws attaching the lugs. A listed terminal bar bolted or attached with threaded machine screws would have been required to correct this.
 
shadowfax said:
In the 2008 NEC, 408.40 states "...Where the panelboard is used with nonmetallic raceway or cable or where separate equipment grounding conductors are provided, a terminal bar for the equipment grounding conductors shall be secured inside the cabinet. ..." This does not indicate that individual lugs are acceptable for multiple equipment grounds. As a former NYC inspector, this would have been grounds for a violation, as well as the self tapping screws attaching the lugs. A listed terminal bar bolted or attached with threaded machine screws would have been required to correct this.
Click to expand...

I can't tell from the blurry photo what types of screws are being used, it's also hard to tell but that may not even be a panelboard in the photo.
 
shadowfax said:
In the 2008 NEC, 408.40 states "...Where the panelboard is used with nonmetallic raceway or cable or where separate equipment grounding conductors are provided, a terminal bar for the equipment grounding conductors shall be secured inside the cabinet. ..." This does not indicate that individual lugs are acceptable for multiple equipment grounds. As a former NYC inspector, this would have been grounds for a violation, as well as the self tapping screws attaching the lugs. A listed terminal bar bolted or attached with threaded machine screws would have been required to correct this.
Click to expand...
Sheet metal screws is an issue if relying on them for bonding. So are machine screws if not engaged at least two threads or if a nut is installed on back side.

mopowr steve said:
Even still it has instruction sticker inside that shows what grounding lugs to use.
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Use of the mentioned bars or lugs in the positions designated for them is simple for the reason the combination of what you have was listed/tested per those instructions. You shouldn't need to scrape any paint, add additional hardware, etc. to use those combinations.

If you choose to use something else forget those instructions and do what NEC says, which may be scraping paint or adding a nut to the back side to assure sufficient securing of the bolt/screw.
 
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