Steel Plaster Ring

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no

no

A round ring is typically used for lighting. Light fixtures and such. The threaded holes on round rings center are 8/32 , on square rings the are 6/32

A single gang square ring will work fine for a 30amp or smaller device, and with devices that have a single yoke.

For 50 amp devices or 4 wires devices , I generally use a two gang ring and a deep foursquare box.
 
rt66electric said:
A round ring is typically used for lighting. Light fixtures and such. The threaded holes on round rings center are 8/32 , on square rings the are 6/32

A single gang square ring will work fine for a 30amp or smaller device, and with devices that have a single yoke.

For 50 amp devices or 4 wires devices , I generally use a two gang ring and a deep foursquare box.
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The 30a or less receptacle will fit through the square opening ?? Thanks
 
This 30 amp twist lock fits in a standard rectangular single gang opening, notice the single yoke and two mounting screws.

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jumper said:
Why not? Maybe I was unclear.

Could you not ground/bond a standard receptacle by removing the insulating washers and mount it directly,metal to metal contact, to a steel plaster ring attached to a bonded steel box?
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No. :)
 
jumper said:
I am guessing Mike meant "remove the tabs" and is referring to 250.146(A) for metal to metal contact for bonding purposes.
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infinity said:
Maybe but that wouldn't apply to a receptacle in a steel plaster ring.
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Thank you for correcting me - I was in a hurry to get out of the door. I mean washers.

The plaster ring is why I brought this up.

314.4 Metal Boxes. Metal boxes shall be grounded and
bonded in accordance with Parts I, IV, V, VI, VII, and X of
Article 250 as applicable, except as permitted in 250.112(I).

Yes a cover is not a box per se but is it a part of a box? I mean if I use a non metallic box and a metal plaster ring does the cover fall under 314.4 ?

Think plaster and lath with metal screen in it. If the ring became energized and was in contact with the metal in the lath it could become energized.

I remember hanging wall paper in a bathroom and was getting shocked touching the walls. Prior to my electrical days. Turned off the breaker no more shock.

So does 314.4 mean only the base of a metal box or would it include the plaster ring making it a 'unit'? Four square (metal) with a single plaster ring (metal) for example. I could bond the box via the plaster ring. Yes/no.

Thoughts?
 
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In this instance this is not a self grounding receptacle. So even if you did remove the fiber washers and installed it to a grounded steel ring or box, you would still be required to provide a ground bonding conductor to the green screw. Self grounding devices have a spring clip on one of the ears that the screw goes through.

-Hal
 
As Hal stated plaster rings would require either a bonding jumper for the receptacle or a self-grounding device. Simply removing one or both fiber/plastic washers wouldn't be acceptable since the box is not surface mounted.
 
hbiss said:
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In this instance this is not a self grounding receptacle. So even if you did remove the fiber washers and installed it to a grounded steel ring or box, you would still be required to provide a ground bonding conductor to the green screw. Self grounding devices have a spring clip on one of the ears that the screw goes through.

-Hal
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Only if the box and ring was flush mount, if surface mounted self grounding receptacles are not required, this also does not apply to switches when metal box's are used, 250.146 clearly allows the ring attached with at least 2 screws to serve as the grounding path of a receptacle that is also connected to the box with two screws and one of the retainer washers removed on surface mounted box's, flush box's the ring is ok but the receptacle needs either a jumper or self grounding clips on the screws, 250.146 does not require this for switches. 404.9(B)(1) allows just the mounting screws on a grounded metal box.
 
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