250.64(E) and Back to Back Panels

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ActionDave

ActionDave

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Single phase 200A service. Service disconnect is back to back to the panel inside with a short piece of EMT connecting them. Load side conductors and the GEC for the water pipe run through the EMT.

I am being told I need to add bond bushings. Is this true?

250.64(E) Enclosures for Grounding Electrode Conductors.
Ferrous metal enclosures for grounding electrode conduc-
tors shall be electrically continuous from the point of attach-
ment to cabinets or equipment to the grounding electrode
and shall be securely fastened to the ground clamp or fitting.
 
The rule calls for the raceway to be electrically continuous. I don't see a need for anything other than the standard locknuts on the raceway terminations.
 
250.92B only refers to service equipment. Downstream of service disconnect is not considered Service Equipment. At least that's the way our utility interprets it. For service equipment, all enclosures and conduits have to be bonded by "approved methods". That means at least one end of service conduits have to have a bonding bushing or other approved device.
 
ActionDave said:
Single phase 200A service. Service disconnect is back to back to the panel inside with a short piece of EMT connecting them. Load side conductors and the GEC for the water pipe run through the EMT.

I am being told I need to add bond bushings. Is this true?

250.64(E) Enclosures for Grounding Electrode Conductors.
Ferrous metal enclosures for grounding electrode conduc-
tors shall be electrically continuous from the point of attach-
ment to cabinets or equipment to the grounding electrode
and shall be securely fastened to the ground clamp or fitting.
Click to expand...

is this not a service?
 
ActionDave said:
Single phase 200A service. Service disconnect is back to back to the panel inside with a short piece of EMT connecting them. Load side conductors and the GEC for the water pipe run through the EMT.

I am being told I need to add bond bushings. Is this true?

250.64(E) Enclosures for Grounding Electrode Conductors.
Ferrous metal enclosures for grounding electrode conduc-
tors shall be electrically continuous from the point of attach-
ment to cabinets or equipment to the grounding electrode
and shall be securely fastened to the ground clamp or fitting.
Click to expand...
You omitted the pertinent part of 250.64(E)...

... Bonding shall apply at each
end and to all intervening ferrous raceways, boxes, and
enclosures between the cabinets or equipment and the
grounding electrode. The bonding jumper for a grounding
electrode conductor raceway or cable armor shall be the
same size as, or larger than, the enclosed grounding electrode
conductor. Where a raceway is used as protection for a
grounding electrode conductor, the installation shall comply
with the requirements of the appropriate raceway article.
Click to expand...
 
Smart $ said:
You omitted the pertinent part of 250.64(E)...
Click to expand...
Thanks for adding that. I did study the entire section. I always thought it only applied when you used a ferrous metal sleeve to protect a GEC.

The part you highlighted in red confuses things. In my opionion both ends of the EMT are electrically continious so I consider them bonded.

Is it your belief there needs to be a bond bushing at each end of the EMT nipple and the GEC attached accordingly?
 
ActionDave said:
...

Is it your belief there needs to be a bond bushing at each end of the EMT nipple and the GEC attached accordingly?
Click to expand...
No.

I sorta jump the gun my last post and didn't post the other pertinent part...

"... Ferrous metal enclosures that are not physically continuous from cabinets or equipment to the grounding electrode shall be made electrically continuous by bonding each end of the raceway or enclosure to the grounding electrode conductor. ..."

I say the disconnect, EMT, and inside panel are physically and electrically continuous. IMO, the only place needing bonded is where the GEC from the electrode(s) enters the inside panel.
 
kwired said:
It is not a service, it is a feeder circuit. Overcurrent device in outside box, feeding a panel inside. If it were a meter outside and the main disconnect inside it would be service equipment in question.
Click to expand...

feeder from disconnect is 4 wires.... let me get my thinking cap back on :dunce:

:lol: i swear i past my masters

coming here i have learned so much more .... probably have opened my code book more in the last couple months than the whole time studying for test:ashamed:
 
Gac66610 said:
is this not a service?
Click to expand...

kwired said:
It is not a service, it is a feeder circuit. Overcurrent device in outside box, feeding a panel inside. If it were a meter outside and the main disconnect inside it would be service equipment in question.
Click to expand...

Gac66610 said:
feeder from disconnect is 4 wires.... let me get my thinking cap back on :dunce:

:lol: i swear i past my masters

coming here i have learned so much more .... probably have opened my code book more in the last couple months than the whole time studying for test:ashamed:
Click to expand...
It doesn't matter whether it is a service or not. 250.64(E) is regarding GEC installation. However, I do not agree with "inspector" in the application of 250.64(E). Enclosures and raceways do not individually need bonded where they are physically and electrically continuous.
 
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Smart $ said:
It doesn't matter whether it is a service or not. 250.64(E) is regarding GEC installation. However, I do not agree with "inspector" in the application of 250.64(E). Enclosures and raceways do not individually need bonded where they are physically and electrically continuous.
Click to expand...

Correct - 250.64(E) is regarding GEC installation. Now we complicate it with a raceway containing both GEC and feeder conductors. Situation that is not specificially addressed so does the raceway still need to comply with 250.64(E) since there is a GEC in it? Take the GEC out of this raceway and I have no question at all about whether or not bonding bushings would be necessary. I also have to ask - does the GEC need to be landed on an EGC bar in the panel it passes through? Can it land on a EGC bus or do you have to make a tap off it with an irreversible connection? I generally would try to avoid running the GEC through the raceway with the feeder like that just to avoid some of these potential problems.
 
kwired said:
Correct - 250.64(E) is regarding GEC installation. Now we complicate it with a raceway containing both GEC and feeder conductors. Situation that is not specificially addressed so does the raceway still need to comply with 250.64(E) since there is a GEC in it? Take the GEC out of this raceway and I have no question at all about whether or not bonding bushings would be necessary. I also have to ask - does the GEC need to be landed on an EGC bar in the panel it passes through? Can it land on a EGC bus or do you have to make a tap off it with an irreversible connection? I generally would try to avoid running the GEC through the raceway with the feeder like that just to avoid some of these potential problems.
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The bonding of the GEC to enclosures and raceways is regardless of any other conductors in the enclosures and raceways.

Properly installed, it is bonded to the service disconnect and its enclosure. It does not exit (i.e. continue through) the enclosure.

The GEC is required to be bonded where it enters and exits all other enclosures and raceways. For continuations where electrically continuous, bonding intermediate entry and exits with jumpers, bushings, and such is not required per 250.64(E). The raceway, properly installed, is bonded (electrically continuous) with service disconnect enclosure and inside panel. Thus the only remaining uncertainty is bonding where it enters the inside panel from the electrode side. No, it does not get bonded to the EGC or EGC busbar. It gets bonded to the enclosure at the point of entry. The jumper or bonding connector does not have to be irreversibly connected to the GEC or the enclosure.

It seems weird that most do not even consider bonding at the point of entry to the service disconnecting means... but add one piece of conduit or another enclosure and it needs bonded where it enters (and exits, if electrically discontinuous).
 
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Smart $ said:
The bonding of the GEC to enclosures and raceways is regardless of any other conductors in the enclosures and raceways.

Properly installed, it is bonded to the service disconnect and its enclosure. It does not exit (i.e. continue through) the enclosure.

The GEC is required to be bonded where it enters and exits all other enclosures and raceways. For continuations where electrically continuous, bonding intermediate entry and exits with jumpers, bushings, and such is not required per 250.64(E). The raceway, properly installed, is bonded (electrically continuous) with service disconnect enclosure and inside panel. Thus the only remaining uncertainty is bonding where it enters the inside panel from the electrode side. No, it does not get bonded to the EGC or EGC busbar. It gets bonded to the enclosure at the point of entry. The jumper or bonding connector does not have to be irreversibly connected to the GEC or the enclosure.

It seems weird that most do not even consider bonding at the point of entry to the service disconnecting means... but add one piece of conduit or another enclosure and it needs bonded where it enters (and exits, if electrically discontinuous).
Click to expand...

You are saying if I leave the service enclosure with a GEC in metal raceway that the GEC needs bonded to raceway at the point it leaves the raceway, and the raceway attachment (if installed properly) should already be bonded to the service enclosure. I totally agree with that.

Are you also saying that if GEC leaves service enclosure through 1/4" hole you still need to bond it at the point of emergence from the service enclosure? I kind of see the reasoning for that but have never seen the bonding done - have seen the GEC leave through a 1/4" hole more times than I could ever remember.
 
kwired said:
You are saying if I leave the service enclosure with a GEC in metal raceway that the GEC needs bonded to raceway at the point it leaves the raceway, and the raceway attachment (if installed properly) should already be bonded to the service enclosure. I totally agree with that.

Are you also saying that if GEC leaves service enclosure through 1/4" hole you still need to bond it at the point of emergence from the service enclosure? I kind of see the reasoning for that but have never seen the bonding done - have seen the GEC leave through a 1/4" hole more times than I could ever remember.
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I'm saying the same thing you have.

Does 250.64(E), or any other section, state "other than the service disconnecting means enclosure" or something to that effect? Not that I'm aware of...
 
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