Does anyone have any information on the use of reducing washers?

UL White Book

OUTLET BUSHINGS AND FITTINGS (QCRV)


That's all I have except they make big holes small.

Thanks Bob- That's what I needed.

That information really makes me question the technical expertise of UL.
Don

Don I think the problem is the difference between test conditions and real life.

I have no doubt you or I could make reducing washers carry fault current if we used a wire brush to remove all paint from the enclosure and tightened the lock nuts decently.

However I know I see reducing washers all the time that are up against paint and loose.

I think an inspector could cite 250.12 Clean Surfaces almost every time.

Personally I dislike everything about reducing washers.

I discussed this matter with the UL representative of CMP 5 (Article 250). He was surprised as well, but looking at the listing standard, it appears as though under test conditions reducing washers that are listed are capable of carrying a tremendous amount of fault current. I don't recall the exat test now, but it was several thousand amps for a substantial duration.

I'm sorry, but if the test conditions do not represent a real world installation, the results are worthless.
Don

I vote with Bob. Reducing washers keep the connector from falling out but I would use a bonding nut if I wanted to make a secure grounding connection.

Reducers -- gotta hate 'em....

Every time I see them it's a hack job.

I particularly dislike reducers used at NEMA3R disconnects where the installer is shrinking back from a 1 inch KO goof.

I hate RE plates. I would rather screw a plate in the can and make sure there is a ground wire. I have had inspectors fail an installation; he wanted reducing washers; I had bolted a cover plate to the top of the box and had a grounding bushing and ground wire in the EMT. My way was better and I proved it to him with a megger. He made me change it to pass inspection. Still scratching my head Rod.

All in favor of eliminating pre-punched knockouts on anything painted grey- raise your hands!

Hand up.

An alternative in many cases is to use reducing bushings with locknuts inside and outside.

An extreme gripe of mine is that small motors come with a 3/4" KO already knocked in them, heavily painted. It's a regular thing to find them with a 1/2" sealtite connector hanging by the conductors, RE washers floating around and a locknut floating on the inside :down:

What is with you guys? I'll bet that at least 1/2% of the times I've come across reducing washers, they have provided a good ground.
I hate those things!

.05% Wow that's bad. Did you mean 50%.

I'm sorry cheap shot but I'm a cheap shot artist.

George, you mean .5%? (cheaper shot)

Found this picture on another site and thought it would say it all.


Thank you, Joe Tedesco

[This message has been edited by jw electric (edited 09-23-2005).]

[This message has been edited by jw electric (edited 09-23-2005).]

[This message has been edited by jw electric (edited 09-23-2005).]

After three trys I get it right, YEA!!


[This message has been edited by jw electric (edited 09-23-2005).]

First off, reducing washers are heavily used in my side of the biz. (Cinemas) Mainly on the flex for the DC leads to the Xenon lamp, though. Seems that the manufacturers of that equipment can't get on the same page and design a standard KO size for a given lamp type.

And did any of you catch the doublespeak in this from the UL white book? (Bold emphasis is added by me.)

It was a test Greg to see if you were watching.