On Oct 10, 10:45*am, bud-- wrote:
On 10/8/2011 7:03 AM, wrote:
On Oct 5, 7:25 pm, wrote:
On Wed, 5 Oct 2011 12:30:40 -0700 (PDT), "
*wrote:
When using a metal junction box, eg handybox for a switch,
is it acceptable code to:
A - Just ground the metal box and rely on the switch getting
grounded by being fastened to the box
B - Just ground the switch and rely on the box getting
grounded by being fastened to the switch
C - Both must be grounded using wire?
Thanks all.
* With switches, the BOX must be grounded - the switch grounds to the
box.
OK, so now we have the switch grounding question
resolved. * But there was mention of a difference for
receptacles? *So, what is the rule for a receptacle
with a metal box?
1. Surface metal box (handybox, ...) with 2 screws securing the
receptacle strap to the box. Often the screws have a paper or similar
disc on the screws to keep them attached to the loose receptacle - at
least one disc has to be removed.
I just installed a Leviton receptacle and 2 Leviton switches, a STSP
and a STDP.
All three devices had a paper disc on 1 screw and a metal bracket that
was riveted to the strap for the other screw.
Here's a pic:
http://i.pgcdn.com/pi/75/87/77/758777524_260.jpg
No need to remove a disc as the devices are "self grounding" -
assuming the box is grounded, of course.
2- Receptacle attaches to metal cover on metal box - all I can think of
are for 4" square boxes. Receptacle has to attach to the cover with 2
screws (a few other requirements). Old covers have the receptacle
attached to the cover with one screw.
* 3. "Self grounding" receptacles with a clip from the yoke to the
screws, metal box.
4. In almost all other cases, a ground wire to the receptacle.
(406.11, 250.146)
And why would one be different
than the other?
Grounding of switches is to ground any metal plates. It should be quite
difficult to get high ground currents.
Grounding of receptacles is to make a good contact for ground return
currents from devices attached to the receptacle through the receptacle
ground pin.
--
bud--- Hide quoted text -
- Show quoted text -