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Old 12-02-2019, 09:31 PM   #1
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Default reducing washers in KO's

Regarding reducing washers, looking for guideance in proper way to install reducing washers. I have always put the raised portion of both washers to face into enclosure. This prevents movement of washer and connector, let's say. I recently spoke with a solar installer who installs them opposite, flat against enclosure and raised portion facing away from opening in enclosure. Feedback?
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Old 12-02-2019, 09:40 PM   #2
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Your way is correct. They can't properly reduce the hole unless they are in the hole. Thr raised portion keeps the washer centered.
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Old 12-02-2019, 09:42 PM   #3
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Depends on how thick the enclosure wall is. I install them with the raised part going in usually, but if the connector bottoms out and does not get tight, then I might put one of them backwards and sometimes both.

Keep in mind that you can not use them as a bond connection as per code so it really doesn’t matter which way you install them, although like Joe just posted, it helps keep them in place when installed inwards
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Old 12-02-2019, 09:45 PM   #4
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Originally Posted by eddy current View Post
Keep in mind that you can not use them as a bond connection as per code so it really doesn’t matter which way you install them, although like Joe just posted, it helps keep them in place when installed inwards
Is that a Canadian code about the reducing washers not being used for bonding?
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Old 12-02-2019, 10:09 PM   #5
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Is that a Canadian code about the reducing washers not being used for bonding?
Yes 10-606(2)

But I assume the NEC has a similar rule no?
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Old 12-02-2019, 10:12 PM   #6
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Yes 10-606(2)

But I assume the NEC has a similar rule no?
It’s allowed , unless the code changed and I overlooked it.
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Old 12-02-2019, 11:47 PM   #7
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If putting both washers the 'right way' results in it being too loose, I'll put one the 'right way' and the other the 'wrong way'. This ensures that the fitting is centered on the oversize hole and also the locknut makes a tight connection.

I've also been known to screw a blank plate (4sq. , 3-0 or 4-0 round) over the oversize hole and punch the correct size KO in it. This is especially handy with larger motors that have sheet steel terminal boxes and huge KOs.

Of course, this violates the listing and who knows how many other equally idiotic regulations...........
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Old 12-02-2019, 11:54 PM   #8
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Quote:
Originally Posted by micromind View Post
I've also been known to screw a blank plate (4sq. , 3-0 or 4-0 round) over the oversize hole and punch the correct size KO in it. This is especially handy with larger motors that have sheet steel terminal boxes and huge KOs.

Of course, this violates the listing and who knows how many other equally idiotic regulations...........
Ha ! We had this problem today, and that solution was mentioned 11/2 KO in the peckerhead, but this one wasn't threaded
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Old 12-03-2019, 02:45 AM   #9
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Quote:
Originally Posted by eddy current View Post
Yes 10-606(2)

But I assume the NEC has a similar rule no?
Quote:
Originally Posted by Awg-Dawg View Post
It’s allowed , unless the code changed and I overlooked it.
Could be a gray are depending on AHJ and brand of reducing washer.

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non-current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any non-conductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

Then you have...
250.12 Clean Surfaces.
Nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuity or be connected by means of fittings designed so as to make such removal unnecessary.


So that says to remove paint or use a washer tested and marked UL to not require removing paint.


UL listing QVRC says
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," for raceways containing other than service conductors. Reducing washers are intended for use with metal enclosures having a minimum thickness of 0.053 in. Reducing washers may be installed in enclosures provided with concentric or eccentric knockouts, only after all of the concentric and eccentric rings have been removed. However, those enclosures containing concentric and eccentric knockouts that have been certified for bonding purposes may be used with reducing washers without all knockouts being removed.

So technically, it depends on the reducing washer listing and the box type and listing. It's a fine point, but could be nit picked. I never have been.

I checked a few suppliers to see if there product was listed and marked for use.

The old Arlington ones on my shelf have no listing, the same with RACO.


Topaz, Crouse Hinds, and T&B did have a listing, and the products are marked with a UL stamp.


So is it compliant? Can you prove it? It depends...
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Old 12-03-2019, 06:05 AM   #10
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Quote:
Originally Posted by CMP View Post
Could be a gray are depending on AHJ and brand of reducing washer.

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non-current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any non-conductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

Then you have...
250.12 Clean Surfaces.
Nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuity or be connected by means of fittings designed so as to make such removal unnecessary.


So that says to remove paint or use a washer tested and marked UL to not require removing paint.


UL listing QVRC says
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," for raceways containing other than service conductors. Reducing washers are intended for use with metal enclosures having a minimum thickness of 0.053 in. Reducing washers may be installed in enclosures provided with concentric or eccentric knockouts, only after all of the concentric and eccentric rings have been removed. However, those enclosures containing concentric and eccentric knockouts that have been certified for bonding purposes may be used with reducing washers without all knockouts being removed.

So technically, it depends on the reducing washer listing and the box type and listing. It's a fine point, but could be nit picked. I never have been.

I checked a few suppliers to see if there product was listed and marked for use.

The old Arlington ones on my shelf have no listing, the same with RACO.


Topaz, Crouse Hinds, and T&B did have a listing, and the products are marked with a UL stamp.


So is it compliant? Can you prove it? It depends...
Any inspector that busts you on this one should have his genitals removed with a hook knife.
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Old 12-03-2019, 06:45 AM   #11
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Any inspector that busts you on this one should have his genitals removed with a hook knife.
Brutal.
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Old 12-03-2019, 07:54 AM   #12
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Quote:
Originally Posted by CMP View Post
Could be a gray are depending on AHJ and brand of reducing washer.

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non-current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any non-conductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

Then you have...
250.12 Clean Surfaces.
Nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuity or be connected by means of fittings designed so as to make such removal unnecessary.


So that says to remove paint or use a washer tested and marked UL to not require removing paint.


UL listing QVRC says
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," for raceways containing other than service conductors. Reducing washers are intended for use with metal enclosures having a minimum thickness of 0.053 in. Reducing washers may be installed in enclosures provided with concentric or eccentric knockouts, only after all of the concentric and eccentric rings have been removed. However, those enclosures containing concentric and eccentric knockouts that have been certified for bonding purposes may be used with reducing washers without all knockouts being removed.

So technically, it depends on the reducing washer listing and the box type and listing. It's a fine point, but could be nit picked. I never have been.

I checked a few suppliers to see if there product was listed and marked for use.

The old Arlington ones on my shelf have no listing, the same with RACO.


Topaz, Crouse Hinds, and T&B did have a listing, and the products are marked with a UL stamp.


So is it compliant? Can you prove it? It depends...
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Old 12-03-2019, 08:18 AM   #13
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Here is the Canadian code. It’s pretty clear that they can not be used for bonding.

10-606
2) Reducing washers shall not be used to maintain the bonding continuity of the wiring system.
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Old 12-03-2019, 08:31 AM   #14
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Originally Posted by eddy current View Post
Here is the Canadian code.

10-606
2) Reducing washers shall not be used to maintain the bonding continuity of the wiring system.
That is so convoluted.
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Old 12-03-2019, 08:36 AM   #15
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Quote:
Originally Posted by eddy current View Post
Here is the Canadian code. It’s pretty clear that they can not be used for bonding.

10-606
2) Reducing washers shall not be used to maintain the bonding continuity of the wiring system.
Quote:
Originally Posted by splatz View Post
That is so convoluted.
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Old 12-03-2019, 10:13 AM   #16
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That is so convoluted.
Yeah it's complicated too.
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Old 12-03-2019, 08:10 PM   #17
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Quote:
Originally Posted by CMP View Post
Could be a gray are depending on AHJ and brand of reducing washer.

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non-current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any non-conductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

Then you have...
250.12 Clean Surfaces.
Nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuity or be connected by means of fittings designed so as to make such removal unnecessary.


So that says to remove paint or use a washer tested and marked UL to not require removing paint.


UL listing QVRC says
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," for raceways containing other than service conductors. Reducing washers are intended for use with metal enclosures having a minimum thickness of 0.053 in. Reducing washers may be installed in enclosures provided with concentric or eccentric knockouts, only after all of the concentric and eccentric rings have been removed. However, those enclosures containing concentric and eccentric knockouts that have been certified for bonding purposes may be used with reducing washers without all knockouts being removed.

So technically, it depends on the reducing washer listing and the box type and listing. It's a fine point, but could be nit picked. I never have been.

I checked a few suppliers to see if there product was listed and marked for use.

The old Arlington ones on my shelf have no listing, the same with RACO.


Topaz, Crouse Hinds, and T&B did have a listing, and the products are marked with a UL stamp.


So is it compliant? Can you prove it? It depends...
All that stuff you said applies to raceways/cables and other supplies.

I would be surprised to see any reducing washers not listed(although I’ve never even paid attention), I would just install them and let the EI duke it out with the manufacturer.
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Old 12-03-2019, 11:20 PM   #18
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Quote:
Originally Posted by Awg-Dawg View Post
All that stuff you said applies to raceways/cables and other supplies.

I would be surprised to see any reducing washers not listed(although I’ve never even paid attention), I would just install them and let the EI duke it out with the manufacturer.
Take it however you like, or don't. Most of the text was quoted from the NEC and UL. Reducing washers are a raceway accessory, so to my knowledge the information is accurate and enforceable.

I just took the time to post it for others, on reducing washer use. For washers that are not listed, I gave two brands as examples. It's a money saving thing to not list them.

As to letting the AHJ duke it out with the manufacturer, that's a good one, I'll need to remember that the next time I ever get a red tag. Southeast Power might be able to use that one in his sealing locknut issue.

Doing a job over again on my dime to clear a reg tag for something silly is not my way. I like to spend the customers money on doing it right the first time, and getting a cut of it.

I have had teaching moments with several AHJ many times over the years, when you can present the facts, and show them the error, they usually become pretty good friends, when approached in the correct manner. But you need to know the facts first.
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