Neutral/grounding lug

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It baffles me why they can't design a lug that can be listed for both the EGC and a neutral. Better yet that should be required by the listing of the lug.
 
infinity said:
It baffles me why they can't design a lug that can be listed for both the EGC and a neutral. Better yet that should be required by the listing of the lug.
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Totally....I wonder sometimes if stuff like this has more to do with "we didn't bother to do the legwork, which is often just paperwork, to get this UL".
 
Does a lug need a different listing depending on what color wire comes into it? I would think that if the lug is rated for the connection methods at both ends (lug to wire, lug to case or whatever), it doesn't matter where it's an EGC or a neutral. (Of course an isolated neutral bar would need the proper standoffs/insulation, but say in a service disconnect.)

Cheers, Wayne
 
infinity said:
It baffles me why they can't design a lug that can be listed for both the EGC and a neutral. Better yet that should be required by the listing of the lug.
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I agree. the one aftermarket lug that is neutral rated for GE that attaches to the rail seems to be much harder to find.
 
wwhitney said:
Does a lug need a different listing depending on what color wire comes into it? I would think that if the lug is rated for the connection methods at both ends (lug to wire, lug to case or whatever), it doesn't matter where it's an EGC or a neutral. (Of course an isolated neutral bar would need the proper standoffs/insulation, but say in a service disconnect.)

Cheers, Wayne
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I think the answer may be this. A ground lug only has to sustain current flow for a few cycles until the OCPD opens up. The neutral lug has to sustain full load indefinitely.
 
petersonra said:
I think the answer may be this. A ground lug only has to sustain current flow for a few cycles until the OCPD opens up. The neutral lug has to sustain full load indefinitely.
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Thanks, that is a plausible distinction, so the next question is whether the listing standards do in fact reflect that distinction, and have different tests for the two types of lugs. And whether the grounding lug test standard is, in fact, less rigorous than the neutral lug testing standard.

If someone points me to the correct UL standard to page through, I'm happy to at least cursorily investigate.

Cheers, Wayne
 
wwhitney said:
Thanks, that is a plausible distinction, so the next question is whether the listing standards do in fact reflect that distinction, and have different tests for the two types of lugs. And whether the grounding lug test standard is, in fact, less rigorous than the neutral lug testing standard.

If someone points me to the correct UL standard to page through, I'm happy to at least cursorily investigate.

Cheers, Wayne
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Try UL 467 for grounding connections and 486A, B and C for other connectors.
 
don_resqcapt19 said:
Try UL 467 for grounding connections and 486A, B and C for other connectors.
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UL 486A-B is spot on for a neutral bar, section 1.1(e) of the Scope is "neutral bars".

I'm a bit unclear on UL 467. The closest scope section is 1.2(b), which reads:

1.2(b) equipment for making electrical connections between
(i) the grounding conductors used in electrical power systems, non-current-carrying metal parts of electrical equipment, armored grounding wires, metal raceways, and the like; and
(ii) grounding electrodes;

If that means connecting any two of the items in (i) or (ii), then it would apply to ground bars. But that would be a strange way to present things; why separate out (ii) grounding electrodes? So I take it to mean connecting any item in (i) to any item in (ii), i.e. to a grounding electrode.

There's also 1.2(a) which reads:

1.2(a) ground clamps, bonding devices, grounding bushings, water-meter shunts, grounding electrodes, and the like used in a grounding system.

So maybe ground bars are "the like"?

Anyway, to the novice reader there is a difference between the tests required in UL 467 and UL 486A-B for terminal bars. Briefly UL 467 requires wire connectors to undergo the "static heating sequence" and the "mechanical sequence" tests of UL 486A-B (or other referenced standard). There's also a test of "short time current" and "thickness of protective coating".

While UL486A-B has a "current-cycling" test in addition to the aforementioned "static heating sequence" and "mechanical sequence" tests. As well as other tests for connectors that involve insulated parts, on the durability/function of the insulating covers.

So as suggested, the difference comes down UL 467 having a "short time current" test with a larger current, and UL486A-B having a "current-cycling test."

But it sounds like if you have a product labeled as "ground bar," if it is listed to UL 486A-B, you can use it as a neutral bar; if not, you can't?

Cheers, Wayne
 
wwhitney said:
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So as suggested, the difference comes down UL 467 having a "short time current" test with a larger current, and UL486A-B having a "current-cycling test."

But it sounds like if you have a product labeled as "ground bar," if it is listed to UL 486A-B, you can use it as a neutral bar; if not, you can't?

Cheers, Wayne
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And that higher short time current for grounding connections was the reason Ideal tried to insist that the only wire nut that could be used for rounding was their Greenie. That insistence resulted in 250.8 including any listed pressure connector as a permitted termination method for grounding.
 
don_resqcapt19 said:
And that higher short time current for grounding connections was the reason Ideal tried to insist that the only wire nut that could be used for rounding was their Greenie. That insistence resulted in 250.8 including any listed pressure connector as a permitted termination method for grounding.
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How does a grounding connection have a higher current than the line conductor?
 
electrofelon said:
How does a grounding connection have a higher current than the line conductor?
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I think that it's more that the grounding connections (UL 467) are tested for fault conditions, as that's the main stressor on them. Whereas as the normally current carrying connections (UL 486A-B) are tested for temperature behavior from current cycling, and not explicitly tested for fault conditions.

Perhaps the assumption is that if it passes the current cycling test, it would pass the short-time current test?

Cheers, Wayne
 
wwhitney said:
I think that it's more that the grounding connections (UL 467) are tested for fault conditions, as that's the main stressor on them. Whereas as the normally current carrying connections (UL 486A-B) are tested for temperature behavior from current cycling, and not explicitly tested for fault conditions.

Perhaps the assumption is that if it passes the current cycling test, it would pass the short-time current test?

Cheers, Wayne
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It was Ideal's assertion that it would not, but of course they wanted to sell more green wirenuts.
 
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