I have a metalic enclosure sandwiched between RNC. I'd like to use a two-terminal landing lug to serve not only as my grounding means but to also splice the grounds (splicing SE cable to THHN). My question is: "Can I use standard bolts, lockwashers, and nuts to fix the lug to the enclosure or must I use some sort of listed components (i.e. specialized nuts, bolts, and washers)?". According to 250.8 (2002 NEC) the stuff must be listed but the folks that I've been talking to have said that standard hardware is good 'nough. My common sense says that standard hardware with lock washers should hold for eternity but I'd like more feedback. I've left messages for the local inspectors without a word back. Any help is appreciated.
By the way, if someone out there has had success with something other than a landing lug, please let me know -- Thanks.

If i am understanding you correctly?
I have done that installation many times and inspection has passed with out any Ifs, Ors and Buts.
However, i am sure you know this the paint of the enclosure must come off first. The lug must make a good mechanical contact with the enclosure.

Edward

PS. where abouts are you in N.Cali.

Standard hardware is OK. Scrape the paint off in the area under the lug. Apply Noalox or coppercoat to make a better connection and
stop rust. I use Stainless.

Thanks for the feedback!
Yea .. on the paint thing I have had success with removing strips of paint by lightly letting my cordless drill "dance" accross the metal with a metal drill bit. Are strips good enough (something tells me "no") or should there not be a stitch of paint under the lug?

P.S. Northern Sacramento (Roseville-Rocklin area)

A drill bit does not work as well as a filler. it is a small 1/4 inch shaft with teeth at the end and on the sides. It is a round file which can be used on a drill motor. It works great.
I would take off paint larger than the area of the lug.Get it down to bare metal.

Edward

Go to the Big Orange Box store and pick up a wire brush for your cordless @ $2.00 it is worth while, it will clean the paint off of any enclosure for a good contact.

Any nuts and bolts are OK just try to size them to the hole in the lug, not really a code issue but using a 1/4" bolt with fender washers on a lug with a 1/2" hole looks real unprofessional in my opinion not to mention you can get far better clamping pressure with the larger bolt.

absolutely, positively remove all the paint . i was called out to a womans home who was getting shocked by her dryer.(1989).
i looked at her panel and found the ground wire had been installed on a mechanical lug added to the panel. i turned off the light in the closet and saw a tiny ball of blue flame at the corner of the lug trying to eat a hole through the paint. after removing the paint the problem was solved.

...What about "tapping" the hole out to accept a 10-32..or 1/4-20 bolt..?? How thick is the enclosure wall??..Granted,paint removal still applies..
Russ

[This message has been edited by Attic Rat (edited 03-15-2004).]

250.8 only covers the lug, which must be listed. The mounting hardware is overlooked.
I asked this question of James Stallcup at a seminar. He said to use stainless with two washers and a locknut. Remove all paint to bare metal. Use an oxide inhibiter like penetrox or copper coat. You may paint the entire assembly, after the inspection.

Earl

It turns out that the landing lug has a quarter inch hole, so the 10-32 screw wouldn't work out unless you really torqued it down. Thanks for the feedback (that goes for all)!

Attic Rat ... caught the 1/4-20 part of the response, ignore the 10-32 portion of the post above. Great Suggestion!

I don't know about the specific UL standard covering the device you are wiring up, but one standard (UL 60950) requires "at least two complete threads into a metal plate, a metal nut or a metal insert" for "screws for electrical contact pressure". Going by that, a 20 thread per inch screw could only be used on minimum .100" metal enclosure. .1 inch is pretty thick - you may not have that much. (I measure .090" on a GE panel in the room I am sitting in right now - that includes the paint) Maybe a finer pitch screw would be in order here.

Although maybe not worth the trouble for fast-track construction work, these are a cool way to bond without tedious paint scraping… Internal-External Tooth Washers — Teeth on both sides let you use washer... for electrical bonding. www.mcmaster.com/param/asp/psearch....,104=4054;138=63200;1515=63023;931=39319

Sez who? Where is the UL bug?