Grounding outlet and switch box

infinity

Moderator
Staff member
I guess I don't know exactly what FS is, but many refer to those like you pictured that are typically water resistant to at least some degree. Simple "handybox" or 4x4 with raised covers are also pretty commonly found surface mounted.

I think your post could be interpreted by some that only those weatherproof boxes like you posted a picture of are allowed to not utilize a bonding jumper to the device, may or may not be what you intended though.

Add: my comment wasn't addressing removing screw retaining non metallic washers as much as it was addressing the need to require a wire bonding jumper, or not.
Got it. In my original post I said "FS like boxes" not thinking that FS wasn't common terminology.

You're correct a handy box would be another type of box (not similar to an FS) where removing the washer to provide the bonding would be permitted. :cool:
 

romex jockey

Senior Member
.

What are you talking about?

(A) Surface-Mounted Box. Where the box is mounted on the
surface, direct metal-to-metal contact between the device yoke
and the box or a contact yoke or device that complies with
250.146(B) shall be permitted to ground the receptacle to the
box. At least one of the insulating washers shall be removed
from receptacles that do not have a contact yoke or device that
complies with 250.146(B) to ensure direct metal-to-metal
contact.
This provision shall not apply to cover-mounted receptacles
unless the box and cover combination are listed as
providing satisfactory ground continuity between the box and
the receptacle. A listed exposed work cover shall be permitted
to be the grounding and bonding means when (1) the device is
attached to the cover with at least two fasteners that are permanent
(such as a rivet) or have a thread locking or screw or nut
locking means and (2) when the cover mounting holes are
located on a flat non-raised portion of the cover
yup...250.146B Bill

~RJ~
 

ramsy

Senior Member
(A) Surface-Mounted Box. Where the box is mounted on the
surface, direct metal-to-metal contact between the device yoke
and the box or a contact yoke or device that complies with
250.146(B) shall be permitted to ground the receptacle to the
box. At least one of the insulating washers shall be removed
from receptacles that do not have a contact yoke or device that
complies with 250.146(B)..
Thanks Bill.

Strange that flush-mount metallic boxes are excluded.
 
Thanks Bill.

Strange that flush-mount metallic boxes are excluded.
I've justified that it applies to surface and not flush because with flush mount, there's a chance that the yoke isn't tight up against the box because of drywall/plaster and therefor not making solid metal to metal contact between yoke and box. With self-grounding receptacles that wouldn't be a problem so only they are ok for flush without the jumper. No?
 

PaulMmn

Senior Member
Let's see... the mounting screw for the duplex outlet goes through the mounting strap and into the hole in the box. The head of the screw, with or without the "don't lose the screw" washer, makes contract with the strap. The threads of the screw make good, solid contact with the box. Now, please explain how removing one of the "don't lose the screw" washers improves conductivity??
 

infinity

Moderator
Staff member
Let's see... the mounting screw for the duplex outlet goes through the mounting strap and into the hole in the box. The head of the screw, with or without the "don't lose the screw" washer, makes contract with the strap. The threads of the screw make good, solid contact with the box. Now, please explain how removing one of the "don't lose the screw" washers improves conductivity??
Because it allows the yoke to make direct contact with the box when using a surface mounted box.
 

ramsy

Senior Member
..with flush mount, there's a chance that the yoke isn't tight up against the box because of drywall/plaster and therefor not making solid metal to metal contact between yoke and box..
Yes, that makes sense.
 

nickelec

Senior Member
Here in NYC inspectors want to see the Bonding jumper from box to device even with self ground devices
even though the whole Installation is metallic I can't seem to locate in the NYC amendments where it's required

Sent from my SM-G965U using Tapatalk
 

infinity

Moderator
Staff member
Here in NYC inspectors want to see the Bonding jumper from box to device even with self ground devices
even though the whole Installation is metallic I can't seem to locate in the NYC amendments where it's required

Sent from my SM-G965U using Tapatalk
Not sure why you're seeing that because it is not required. We have been using MC-ap for years with self-grounding receptacles and never install a bonding jumper to the box. Here are all of the NYC electrical code amendments for Article 250:

NYC 2011 Electrical Code Technical Provisions

ARTICLE 250
Grounding and Bonding
SECTION 250.52
Subsection 250.52(A)(1) – Delete the Exception in its entirety.
 

kwired

Electron manager
Let's see... the mounting screw for the duplex outlet goes through the mounting strap and into the hole in the box. The head of the screw, with or without the "don't lose the screw" washer, makes contract with the strap. The threads of the screw make good, solid contact with the box. Now, please explain how removing one of the "don't lose the screw" washers improves conductivity??
Though I never did this with receptacles, which also need to pass the EGC onto whatever is plugged into them, I have taken this approach before with switches and had inspector shoot it down even though it sort of doesn't make any sense. But I somewhat reluctantly changed it because wording in code says what it says.
 

mbrooke

Senior Member
Not sure why you're seeing that because it is not required. We have been using MC-ap for years with self-grounding receptacles and never install a bonding jumper to the box. Here are all of the NYC electrical code amendments for Article 250:
Is NYC still on the 2011 modified code?
 
Top