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| Subject - Plastic box - metal raised roughing cover | |
| Pierre Belarge |
When installing a metal raised roughing cover to a plastic 1900 box, is it required to bond the raised roughing cover if the device(s) has a bonding conductor connected to it?  If so, why, and how would you do it. Pierre |
| iwire | Pierre IMO the metal ring must be bonded. Is there a way to do this in a code compliant manner? IMO yes I could drill a hole in the ring and either tap the hole for a machine screw or use a nut and bolt to attach a bonding conductor. If drilling a hole for grounding purposes is a violation I would be interested to see how others ground the enclosures of large transformers. Few come with a grounding terminal. 
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| iwire | Oh I forgot......Why in the world would anyone want to do this? Get a metal box or a plastic ring Home Depot has both. Bob |
| Ryan_J | In my opinion, the device's 6-32 screws bond the plaster ring and nothing else is required. We allow a metal plaster ring to ground a switch if there is metal to metal contact, why wouldn't the opposite hold true? I think 250.4(A)(5) would require it. |
| iwire | quote: IMO that conflicts with 250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes. Once the device is removed you have lost grounding continuity. I guess this one is over my head we don't use plastic boxes or rings.
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| Ryan_J | Thats a good point Bob. I've never put much thought into this either, kind of an oddball, isn't it? |
| Pierre Belarge | I believe the ring needs to be bonded regardless of the device connection. The way we do it here is with a grounding clip, with either a tail to the device or selfgrounding devices. |