sheet metal screws

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monkey

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I am aware self tapping or sheet metal screws cannot be used for grounding or bonding, but I was tagged today for attaching the plastic mounts of a floating neutral bar to the enclosure with self tapping screws. The inspector cited 250.8. Is he right?
 
If the screws were used to mount the bar, and not provide the mechanical/electrical connection, then I'd say he's misinterpreted the code section.
 
250.8 is for conductors and bonding jumpers only... maybe he could say 110.3(B), but I don't know what hardware, if any, came with the neutral bar you installed
 
What does the plastic bar mount have to do with threaded machine screws? Did he cite a particular violation? IMO he's incorrect unless there is a listing issue with using the screws that came with the bar. To me that's a stretch.

Were they tapped holes that you used already in the panel?
 
infinity said:
What does the plastic bar mount have to do with threaded machine screws? Did he cite a particular violation? IMO he's incorrect unless there is a listing issue with using the screws that came with the bar. To me that's a stretch.

Were they tapped holes that you used already in the panel?
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I didn't read that they came with the bar. Just that sheet metal screws were used. Not that its right or wrong, I just don't think I'd do it that way:)
 
It was a former main panel converted to a sub panel. I installed a grounding buss with 10/32s, and I removed the neutral bus, placed plastic mounts under it, and fastened it to one threaded hole with a 10/32, the other with a TEK screw since there was no second hole. I couldn't tap the second hole because the enclosure is mounted on a brick wall with a ramset. The only way I can tap it is to destroy my drill/tap when it plows into the concrete.

360, I use those all the time. Looks like I'll be buying a new 10/32 tho.
 
I just use a tek screw to make a pilot hole, reverse it out, and then chuck in a tap threader directly into the chuck of my cordless and tap the hole. I carry the 10--32 tap with me at all times in my pouch for making bonding screw holes where none existed before I got there. Always got a few tek screws and 10-32 screws bouncing around in my bags somewhere.
 
monkey said:
It was a former main panel converted to a sub panel. I installed a grounding buss with 10/32s, and I removed the neutral bus, placed plastic mounts under it, and fastened it to one threaded hole with a 10/32, the other with a TEK screw since there was no second hole. I couldn't tap the second hole because the enclosure is mounted on a brick wall with a ramset. The only way I can tap it is to destroy my drill/tap when it plows into the concrete.

360, I use those all the time. Looks like I'll be buying a new 10/32 tho.
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He is way off base. 250.8 refers to Grounding and bonding equipment , not nuetral bars. What he should have called was UL listing violation.;)
 
acrwc10 said:
I was looking at those and wondering if they were any good, Now I am going to buy them. They look like they are faster them a box tap.
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Better hurry; I just bought one and there's only one left.

Actually, there are a few others, but not all have the box with the quick-change holder.
 
mattsilkwood said:
ive got a set and love em, but i make a pilot hole the put the tap in my
10 in 1 works out slick. ive broke a few in the cordless ecspecialy the small ones.
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What is a 10 in 1?
 
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mattsilkwood said:
ive got a set and love em, but i make a pilot hole the put the tap in my
10 in 1 works out slick. ive broke a few in the cordless ecspecialy the small ones.
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Yeah, I've broke more than one because it torqued on me before I could stop it. I use them in nut drivers/10-in-1 at times for that reason, as long as I can keep the right size drill bit long enough. :roll:

monkey said:
I couldn't tap the second hole because the enclosure is mounted on a brick wall with a ramset. The only way I can tap it is to destroy my drill/tap when it plows into the concrete.
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It's kind of hard to do with hardware that small, but sometimes you can start with a smaller hole through the enclosure, than a masonry bit to open the concrete and make room for your tap bit. One--it's hard to find a masonry bit that small, two--by the time you go through all that, just get a new tap bit.:grin:
 
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