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#95560 09/21/05 05:32 PM
Joined: Jan 2004
Posts: 1,507
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Member
Does anyone have any information on the use of reducing washers?


George Little
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#95561 09/21/05 05:37 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
UL White Book

OUTLET BUSHINGS AND FITTINGS (QCRV)

Quote
GROUNDING
Metal reducing washers are considered suitable for grounding for use in
circuits over and under 250 V and where installed in accordance with
ANSI/NFPA 70, ‘‘National Electrical Code.’’

That's all I have except they make big holes small. [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#95562 09/21/05 06:01 PM
Joined: Jan 2004
Posts: 1,507
G
Member
Thanks Bob- That's what I needed.


George Little
#95563 09/22/05 07:29 AM
Joined: Nov 2000
Posts: 2,148
R
Member
That information really makes me question the technical expertise of UL.
Don


Don(resqcapt19)
#95564 09/22/05 09:09 AM
Joined: Jan 2003
Posts: 4,391
I
Moderator
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.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#95565 09/22/05 09:30 AM
Joined: Aug 2003
Posts: 1,374
R
Moderator
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.


Ryan Jackson,
Salt Lake City
#95566 09/22/05 11:45 AM
Joined: Nov 2000
Posts: 2,148
R
Member
I'm sorry, but if the test conditions do not represent a real world installation, the results are worthless.
Don


Don(resqcapt19)
#95567 09/22/05 02:22 PM
Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
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.


Greg Fretwell
#95568 09/22/05 07:27 PM
Joined: Jun 2004
Posts: 1,273
T
Member
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.


Tesla
#95569 09/22/05 08:48 PM
Joined: Jan 2005
Posts: 109
L
Member
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.

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