ECN Forum Forums Code Related Discussion NEC & other Code issues Plaster rings and 4 wire 30A outlet

I put in two outlets:
50A 4 wire in kitchen
30A 4 wire in laundry

in both cases I put a 4 inch square box and a 1 gang plaster/switch ring on the box.

The 50A outlet fit into the 1 gang ring
The 30A outlet did not fit into the 1 gang ring without widening the ring.

I'm often not clear, hope this explains it

Thanks,

jfw11:

I'm not sure if this is exactly what is meant here*, but relative to 4" square boxes with a metal plate on the front, the number of wires supposedly makes no difference with regard to the size of the opening. Here's what Steel City lists in their literature:



However, I had the same thing happen--the old plate was not compatible with the 4-wire receptacle on a 30AMP dryer circuit. Wheeeee!
__________
*I am not an electrician, so as to the "plaster rings", "switch rings", etc., I don't know if I'm thinking of the same thing that is mentioned in the posts above. I thought a "surface outlet" was this:


jfw11: It's not that you are not clear, it's that there are so many names for things, between "generic" names and trade names that are picked up.

[This message has been edited by ThinkGood (edited 08-14-2003).]

I guess I stand corrected..kinda.
Appleton and T&B call them "device covers"
Bowers calls them "switch rings".
Hubbell/Raco calls them "mud rings"
(I guess they're all plaster rings).

[This message has been edited by electure (edited 08-17-2003).]

Thinkgood both items you show are good for surface installations.

For recessed or flush installations

30 amp we use a 4"sq Deep box with a two gang "plaster ring" that makes a 4" sq box have the front dimensions of a two gang box but leaves more volume for conductors in the rear.

50 amp we use a 4 11/16" sq Deep box with a two gang "plaster ring" that makes a 4 11/16" sq box have the front dimensions of a two gang box but leaves even more volume for the larger 50 amp conductors in the rear.

This may seem like overkill but when putting in the devices it goes much quicker and there is no question of having the required conductor space.

Do not forget that 300.14 requires 6" free conductor and on a box of this size 3" outside the box, using 6 AWG on the 50 amp outlet makes getting this much conductor in the box a bit tough.

99% of our work is commercial, the only boxes we use are 4" deep and 4 11/16" deep boxes.

To that we add plaster rings single, double, round etc.

The boxes have no mounting bracket we use Caddy H-23s

The one on the right is as close as I could find to how we do it, plaster ring / Caddy bracket / 4" sq box

Caddy

Bob


[This message has been edited by iwire (edited 08-16-2003).]

iwire:

That Caddy looks neat. Figures it's made by ERICO. They also make CADWELD. I've never actually used one, but "Can carry more current than the conductor" sounds pretty strong to me!