Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
I have been reading a lot of material regarding the 2014 NEC. So my brain may be a little scrambled.
Metal reducing washers were mentioned in a document on UL's website that I happen to have come across.
I have 2 questions.
1. When installing the metal reducing washers, and they become part of the effective ground fault path (such as using them with EMT), is it required to remove the paint from the surface of the enclosure (both inside and outside the enclosure), if the surface is painted, to keep the effective ground fault current path "effective?" 250.12 Clean Surfaces
If so, is any one actually doing so?
2. This same document states that the reducing washers can be used for Service Entrance Conductors.
I have read the UL White Book and do not see where it says they can be used for Service Entrance Conductors????
From (QCRV)UL - 2013
"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.?? Reducing washers are
intended for use with metal enclosures having a minimum thickness of
0.053 in. for non-service conductors only. 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."
When I read 'official' documents on a website, especially one such as UL, I generally take the info as gospel. This time I have read it and am not so sure this is in fact correct.
Thanks for the help here.
Metal reducing washers were mentioned in a document on UL's website that I happen to have come across.
I have 2 questions.
1. When installing the metal reducing washers, and they become part of the effective ground fault path (such as using them with EMT), is it required to remove the paint from the surface of the enclosure (both inside and outside the enclosure), if the surface is painted, to keep the effective ground fault current path "effective?" 250.12 Clean Surfaces
If so, is any one actually doing so?
2. This same document states that the reducing washers can be used for Service Entrance Conductors.
I have read the UL White Book and do not see where it says they can be used for Service Entrance Conductors????
From (QCRV)UL - 2013
"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.?? Reducing washers are
intended for use with metal enclosures having a minimum thickness of
0.053 in. for non-service conductors only. 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."
When I read 'official' documents on a website, especially one such as UL, I generally take the info as gospel. This time I have read it and am not so sure this is in fact correct.
Thanks for the help here.
