puzzler no egc with service

[PEDRO ESCOVILLA]

:happysad:existing installation, disconnect below meter, driven rod, gec bonded to neutral at 1st disconnect. 3 wire run into bldg, no egc run with feeders to interior panel. fire in bldg, doesn't affect panel, however, owner decides to have sparkmeister install new panel while fixing fire damage. there is no egc with feeders to panel, sparky bonds interior panel with bonding screw provided. i say take it out (bonding screw) and pull in an egc, sparky says theres an lb buried in the wall. i believe they may (will have to expose it) have to find the lb to get an egc to that panel, any ideas

 

[Cow]

Not having looked at the job, I might be inclined to install or attach to an existing grounding electrode system in this SEPERATE building and treat it like a new service. There are a lot of existing 3 wire services still in use today. Since yours is fed from a pole it sounds highly unlikely that you have any other metallic paths in parallel with the grounded conductor making this installation still legal.

 

[charlie b]

I agree with you, Pedro. The N-G bond takes place at the first disconnect, and never again at a downstream location. Yours takes place at the disconnect below the meter. You need an EGC from there to the panel, and the N-G bond must be removed at the panel. Reference 250.24(A)(5) {2011 NEC}.

 

[augie47]

I agree that the proper install would be to install an EGC.
That said, as Cow referenced, the job may have been compliant when installed.
I would imagine since no new feeder is being installed a number of inspectors would allow the install as "repair to existing".. a stretch I will admit, but I have seen such.
You are faced with an "alteration" of an existing situation which was possibly Code compliant and possibly operated safely for years. Addressing those is always a tough call.

 

[hurk27]

Not having looked at the job, I might be inclined to install or attach to an existing grounding electrode system in this SEPERATE building and treat it like a new service. There are a lot of existing 3 wire services still in use today. Since yours is fed from a pole it sounds highly unlikely that you have any other metallic paths in parallel with the grounded conductor making this installation still legal.

I'm still trying to find the "pole" mounted service in the OP?:?


If the raceway between the service disconnect and the inside subpanel is metallic then remove the bonding screw, install a grounding bar, and call it a day, if it's non-metallic then as was said you need an EGC.

 

[jumper]

Is the meter and disconnect on the building?

 

[renosteinke]

This does not strike me as a violation of the neutral/ground separation issue. Instead, it seems more like they are using the conduit as a EGC.

We can do this for branch circuits, but not for feeders. This circuit is a feeder. Today, this would be a violation. So, the question is: can we rely upon the pipe to carry the fault current necessary to trip the main?

If it's threaded pipe, I might be content to take the chance; maybe add a few bonding bushings at the connections.

One other detail bothers me. Is there overcurrent protection at the main disconnect? If so, then that is the proper place to separate the ground from the neutral. If it's only a switch, then the panel is the correct place- and the bond at the disconnect should be removed.

 

[Cow]

I'm still trying to find the "pole" mounted service in the OP?:?

You know, me too...? Where did I see that?:roll:

I saw a 3 wire feeder ran into building and somehow got it in my head there was a seperate pole mounted service. If this is all mounted on/in the same building, then I absolutely agree, you should pull the 4th wire.

 

[kwired]

This does not strike me as a violation of the neutral/ground separation issue. Instead, it seems more like they are using the conduit as a EGC.

We can do this for branch circuits, but not for feeders. This circuit is a feeder. Today, this would be a violation. So, the question is: can we rely upon the pipe to carry the fault current necessary to trip the main?

If it's threaded pipe, I might be content to take the chance; maybe add a few bonding bushings at the connections.

One other detail bothers me. Is there overcurrent protection at the main disconnect? If so, then that is the proper place to separate the ground from the neutral. If it's only a switch, then the panel is the correct place- and the bond at the disconnect should be removed.

Where does it say raceway can be used as EGC for branch circuits but not for feeders? I'm pretty sure it does not say that anyplace in NEC. I have seen branch circuits many times that are larger capacity than a feeder on same premesis - size of circuit has nothing to do with it.

 

[PEDRO ESCOVILLA]

ok, here I am again, conduit won't work for an EGC as its PVC below the meter ON THE POLE, ABOVE THE FIRST POINT OF DISCONNECT, at which point the neutral and gec are bonded. now, it runs 3 wire (240/120) in to a panel in the interior of the building, (somewhere below grade they transition to EMT, or somewhere in the building, as I said, it's all existing, i cant see a lot of it, it's buried or behind walls)with no ECG, however, he ran the bonding screw into to the tub, which is, I think , fruitless, he needs to pull a ECG

 

[charlie b]

OK, based on that clarification, I will revise my response. The incoming wires are still "service conductors," until they get to the first overcurrent device (not just the first disconnecting means). That appears to be inside the building, at the panel (presuming it is a main breaker panel). So the N-G bond should take place at the panel, there should be a grounding electrode conductor going from the neutral bar to a grounding electrode system, you only need three wires (not an EGC) coming into the building, and the N-G bond and ground rod at the pole are irrelevant. I will also mention that the panel should have a main breaker, or there should be some other disconnecting means (the one on the pole does not count) to allow all power to be removed from the building.

 

[renosteinke]

Kwired ....

That a feeder cannot rely upon the conduit alone as the EGC is implied in 215.2(A)(2), where it states that the size of the feeder grounded conductor shall not be smaller than that required by 250.122 ....

Now, I cannot find any reference in 250.122 to the ampacity of steel pipe, of whatever wall thickness- only to copper and aluminum wire. If, perhaps, I overlooked some table listing the ampacity of 3/4" EMT, I'm open to correction.

 

[charlie b]

Now, I cannot find any reference in 250.122 to the ampacity of steel pipe, of whatever wall thickness- only to copper and aluminum wire.

That is because, (1) 250.122 is specifically about EGCs "of the wire type," as it says in its opening sentence, and (2) We do not speak of EGCs in terms of ampacity, but rather in terms of their sizes. Take a look at 250.118.

 

[jumper]

OK, based on that clarification, I will revise my response. The incoming wires are still "service conductors," until they get to the first overcurrent device (not just the first disconnecting means). That appears to be inside the building, at the panel (presuming it is a main breaker panel). So the N-G bond should take place at the panel, there should be a grounding electrode conductor going from the neutral bar to a grounding electrode system, you only need three wires (not an EGC) coming into the building, and the N-G bond and ground rod at the pole are irrelevant. I will also mention that the panel should have a main breaker, or there should be some other disconnecting means (the one on the pole does not count) to allow all power to be removed from the building.

If the disconnect is not an OCPD, fused or breaker, then we still got a problem.

230.91 Location. The service overcurrent device shall be
an integral part of the service disconnecting means or shall
be located immediately adjacent thereto.

 

[renosteinke]

Article 215 ("Feeders") simply states that the EGC SHALL be sized in accordance with 250.122. Since 250.122 is ONLY for 'wire type" EGC's, I infer that only wire type EGC's are allowed.

Article 215 goes on to say that the EGC must be identified in accordance with 250.119, so I have to ask: does this mean we have to paint the pipe green? Again, there seems to be a presumption that the EGC for a feeder is a wire, and not the pipe.

While I am certain a better citation exists, I haven't found it ... yet. I know I've seen it, but where.... ?

 

[jumper]

Article 215 ("Feeders") simply states that the EGC SHALL be sized in accordance with 250.122. Since 250.122 is ONLY for 'wire type" EGC's, I infer that only wire type EGC's are allowed.

Article 215 goes on to say that the EGC must be identified in accordance with 250.119, so I have to ask: does this mean we have to paint the pipe green? Again, there seems to be a presumption that the EGC for a feeder is a wire, and not the pipe.

While I am certain a better citation exists, I haven't found it ... yet. I know I've seen it, but where.... ?

How about 250.118?

 

[hurk27]

If the disconnect is not an OCPD, fused or breaker, then we still got a problem.

230.91 Location. The service overcurrent device shall be
an integral part of the service disconnecting means or shall
be located immediately adjacent thereto.

Remember the disconnect on the pole is not required by the NEC, if it is there then its just another way to turn off the power but is not a required disconnect so there is no requirements for OCPD. see 230.70

As far as the NEC is concerned you could just mount the meter on the pole, then run to the building then have your disconnect and OCPD's

 

[renosteinke]

250.118 described EGC's of many types, including conduit. It's a general description of EGC's.

217 discusses feeders in the specific. 217 is worded in a manner that refers only to wire-type EGC's. I infer from this that only wire-type EGC's are acceptable, as the 'specific' overrules the 'general.'

That's how I see it. Rather like a town having a 'general' speed limit of 25mph, but that limit being overruled by a sign in a specific area.

 

[kwired]

Kwired ....

That a feeder cannot rely upon the conduit alone as the EGC is implied in 215.2(A)(2), where it states that the size of the feeder grounded conductor shall not be smaller than that required by 250.122 ....

Now, I cannot find any reference in 250.122 to the ampacity of steel pipe, of whatever wall thickness- only to copper and aluminum wire. If, perhaps, I overlooked some table listing the ampacity of 3/4" EMT, I'm open to correction.

Must be from 2011 NEC, I find what you are saying in 2008 in 215.2(A)(1), but that is talking about the grounded conductor (the neutral in most cases). 215.6 is all I see in 215 that tells us what to do with the equipment grounding conductor.

215.6 tells us to comply with 250.134.

250.134(A) tells us it can be any type permitted by 250.118.

250.118 allows different conductor types and also specificially mentions just about every type of metal raceway there is as being suitable for use as an equipment grounding conductor.

 

[infinity]

Kwired ....

That a feeder cannot rely upon the conduit alone as the EGC is implied in 215.2(A)(2), where it states that the size of the feeder grounded conductor shall not be smaller than that required by 250.122 ....

Now, I cannot find any reference in 250.122 to the ampacity of steel pipe, of whatever wall thickness- only to copper and aluminum wire. If, perhaps, I overlooked some table listing the ampacity of 3/4" EMT, I'm open to correction.

There is nothing written or implied in 215.2(A)(2) that the EGC cannot be a metallic raceway.