250.146 Again.......

[San -Brooke]

If a receptacle is being fed through a raceway that does in fact meet NEC requirements as providing EGC (such as EMT,Rigid, IMC etc...) from the supply(panel board) to a box then why would you ever require to bond to the box(4x4, FS, bell box, etc...) if you pull a ground wire to the device? If you refer to the NEC hanbook on page 277 exhibit 250.59 it illustrates an IG receptacle with a grounding conductor going directly to the device and illustrates the metal raceway(EMT and box) as providing a suitable grounding means without pulling a second grounding conductor. So if that is the case then why would it be necessary to gound to the box just because you would have continuity between the receptacle and yoke?

 

[texie]

If a receptacle is being fed through a raceway that does in fact meet NEC requirements as providing EGC (such as EMT,Rigid, IMC etc...) from the supply(panel board) to a box then why would you ever require to bond to the box(4x4, FS, bell box, etc...) if you pull a ground wire to the device? If you refer to the NEC hanbook on page 277 exhibit 250.59 it illustrates an IG receptacle with a grounding conductor going directly to the device and illustrates the metal raceway(EMT and box) as providing a suitable grounding means without pulling a second grounding conductor. So if that is the case then why would it be necessary to gound to the box just because you would have continuity between the receptacle and yoke?

Yes, it does seem like a contradiction. Been that way since I can remember.

 

[A/A Fuel GTX]

I believe it's beacuse the contact between the yoke and the device box is not considered an adequate ground path.

 

[GoldDigger]

I believe it's beacuse the contact between the yoke and the device box is not considered an adequate ground path.

Some devices (switches, receptacles) are available in special construction which carries a listing approval for the yoke to be used for bonding. (Assuming that the right screws, etc. are used.)
In the absence of that listing, the yoke is, as mentioned, not rated or tested for bonding.

 

[texie]

Some devices (switches, receptacles) are available in special construction which carries a listing approval for the yoke to be used for bonding. (Assuming that the right screws, etc. are used.)
In the absence of that listing, the yoke is, as mentioned, not rated or tested for bonding.

Yes, you are referring to self grounding receptacles. But that is not what the OP is referring to (I think). He is saying if it is an isolated ground recep/install you don't have to have an EGC connected to the box, but if it was a standard recep. and you chose to run an EGC even though the raceway qualified as an EGC you still have to connect the EGC to the box.

 

[MarineTech]

This is just my personal thing, but if it is up to me, even if I use something like a Leviton Decora Commercial Side Wire Duplex Receptacle Outlet, which has a yoke self grounding screw connection to a metal box, I prefer to include a green ground wire and not rely solely on the self-grounding yoke screw attachment. On residential grade, I do not see the self grounding option.

 

[San -Brooke]

Yes, you are referring to self grounding receptacles. But that is not what the OP is referring to (I think). He is saying if it is an isolated ground recep/install you don't have to have an EGC connected to the box, but if it was a standard recep. and you chose to run an EGC even though the raceway qualified as an EGC you still have to connect the EGC to the box.

Exactly!!!!! Thanks texie! I see absolutely no reason to have to provide a bonding jumper if you run a seperate EGC from the panel when by NEC standards you did not have to run the ground in the first place but just run a bonding jumper to the device. For what reason should you have to bond the box when by code it is already an EGC? And in reality what safety issue is that bonding jumper protecting you from? That when you remove the device you may be shocked by a metal plaster ring?

 

[texie]

Exactly!!!!! Thanks texie! I see absolutely no reason to have to provide a bonding jumper if you run a seperate EGC from the panel when by NEC standards you did not have to run the ground in the first place but just run a bonding jumper to the device. For what reason should you have to bond the box when by code it is already an EGC? And in reality what safety issue is that bonding jumper protecting you from? That when you remove the device you may be shocked by a metal plaster ring?

I guess that is just one of the quirks of the NEC.

 

[jap]

I didnt think you had to run a jumper from the receptacle to the box if they were the self grounding type.
I thought the 6/32's bonded the receptacle to the box and the jumper was not required, or am I
remembering this all wrong?

 

[infinity]

I didnt think you had to run a jumper from the receptacle to the box if they were the self grounding type.
I thought the 6/32's bonded the receptacle to the box and the jumper was not required, or am I
remembering this all wrong?

He's asking if you had a metallic raceway and a wire type EGC why would you need to connect the wire type EGC to the box. The same installation with an IG receptacle requires no such connection between the wire type EGC and metal box.

 

[Smart $]

He's asking if you had a metallic raceway and a wire type EGC why would you need to connect the wire type EGC to the box. ...

The NEC is chock full of redundancy when it comes to grounding...

 

[infinity]

The NEC is chock full of redundancy when it comes to grounding...

I agree and not all of it, like this example, actually make any sense. This is up there with requiring a #10 EGC for a 20 amp circuit in EMT when pulling a #10 ungrounded conductor.

 

[jap]

The same installation with an IG receptacle requires no such connection between the wire type EGC and metal box.

I thought once the Isolated Ground receptacle came into play then you default to the requirements
of 250.96B Which requires you to install a Supplemental Insulated Equipment grounding conductor to
ground the equipment enclosure, meaning you would be required to install (2) insulated equipment
grounding conductors. One for the isolated ground (that would go to the isolated ground terminal on the
receptacle) and one for the equipment ground (That would bond to the box).

Therefore only having an isolated ground wire and considering the conduit as the equipment grounding
conductor would not be allowed.

 

[Smart $]

I thought once the Isolated Ground receptacle came into play then you default to the requirements
of 250.96B Which requires you to install a Supplemental Insulated Equipment grounding conductor to
ground the equipment enclosure, meaning you would be required to install (2) insulated equipment
grounding conductors. One for the isolated ground (that would go to the isolated ground terminal on the
receptacle) and one for the equipment ground (That would bond to the box).

Therefore only having an isolated ground wire and considering the conduit as the equipment grounding
conductor would not be allowed.

250.96(B) is regarding the isolation of an enclosure. In this case a non-metalic conduit, either an entire run or just a short section or fitting, is used to isolate the enclosure. In this case, a wire EGC would be required for bonding the enclosure... but it could be the same isolated EGC as a receptacle enclosed therein.

 

[jap]

250.96(B) is regarding the isolation of an enclosure. In this case a non-metalic conduit, either an entire run or just a short section or fitting, is used to isolate the enclosure. In this, a wire EGC would be required for bonding the enclosure... but it could be the same isolated EGC as a receptacle enclosed therein.

I realize that, but, isnt an IG Receptacle the same scenario?

 

[jap]

Never mind, I see the point. We've just always installed (2) insulated Ground Wires, (1) for the IG
and (1) for the EGC, its just always been spec'd that way on every job I can recall.

Dont know that we've ever used just the conduit only for the EGC.
Even if it was allowed it was always spec'd to install an EGC along with the circuit conductors.

I guess it's all in what you've been brought up around.