joshuawcurtis
New User
- Location
- Michigan/Indiana
I recently saw a video and read some post about reducing washers being rated for grounding and bonding. We have to remember that listing correlate to a testing facility doing test under the ideal conditions given by the manufacturer or by similar product listings. Most grounding and bonding devices assume the box is unpainted steel in dry environment that is not a classified explosion-proof area. Some panel and disconnects are rated at their ampacity not considering the use of reducers and/or KO plugs. Also they are not listed to be used with certain connectors such as LFMC and ridged hubs.
From: 2015-16 GUIDE INFORMATION FOR ELECTRICAL EQUIPMENT — THE WHITE BOOK
OUTLET BOXES AND FITTINGS (QBPZ) OUTLET BOXES (page 405)
"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."
From: 2015-16 GUIDE INFORMATION FOR ELECTRICAL EQUIPMENT — THE WHITE BOOK
OUTLET BOXES AND FITTINGS (QBPZ) OUTLET BOXES (page 405)
"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."
