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Old 01-23-2012, 10:38 PM   #1
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Subpanel WITH bonded neutral


I know, I know, it's like beating a dead horse. But, I'm a little perplexed and my computer is down so reading the online code is difficult.

Anyway, rural setting. POCO service enters a pole mounted service head, down the pipe and into the meter box. Mounted to the bottom of the meter box is a service disconnect. From there the service conductors (3- wire) travel back up the pipe (service loop?), exit the service head, and are strung overhead to another service head at the dwelling. This service head is attached to an exterior panel mounted on the dwelling. There is no main disconnect at this panel. There is an EGC and ground rod installed at this panel.

Again, this panel is not the location of the service disconnect. So is this an example of a subpanel which requires the neutral and ground bars to be bonded? Or is this a main panel with a missing service disconnect?

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Old 01-23-2012, 11:05 PM   #2
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Subpanel WITH bonded neutral


Great post!! Looking forward to the responses as I may have a similar application.

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Old 01-23-2012, 11:25 PM   #3
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Can you post pictures?
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Old 01-23-2012, 11:30 PM   #4
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No...not immediately. It's in-laws house 100 miles away. I thought my description was pretty good.
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Old 01-23-2012, 11:52 PM   #5
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Quote:
Originally Posted by jlmran View Post
No...not immediately. It's in-laws house 100 miles away. I thought my description was pretty good.
Not really, due to it leaves too much amiss. My thought is all they are doing, is using the meter pan as a pass through, not anywhere as a disco, unless it goes into a breaker and back out at that point.
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Old 01-23-2012, 11:55 PM   #6
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Yes...the service disconnect is a 2-pole breaker, immediately after the meter.

What is amiss?
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Old 01-24-2012, 12:04 AM   #7
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Subpanel WITH bonded neutral


The first disconnect should be grounded even if the lateral aerial line doesn't also have a ground with it.

ETA: missed that the load side off that disconnect is in same conduit as feed.
This is a "Real Bad Idea".

But until the power goes through a FUSED or breakered disconnect
(of some sort) ... I say it's still the feed and doesn't get the N/G split.

But I also say... that the "exterior panel mounted on the dwelling" should have a main.
Quote:
is this an example of a subpanel... NO.
Or is this a main panel with a missing service disconnect? also NO
Not missing... just not up to current specs.

So... when are you going to fix this place up?

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Old 01-24-2012, 12:25 AM   #8
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The first (and only) disconnect is grounded (bonded) to the POCOs copper conductor which runs the length of the pole.

The overhead conductors (after meter and disconnect) is 3-wire. Thus, the panel fed by these conductors requires a N/G bond. Otherwise you have no function or no safety.

I guess what exists is a main panel which has it's main disconnect located elsewhere (on the pole). A remotely controlled main panel, if you will.

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Old 01-24-2012, 01:15 AM   #9
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You've got some problems with this setup, no matter what code cycle is was built under. The first and most obvious issue is that the service entrance conductors share a conduit with the conductors leaving the disconnect. This is not permissible - nothing can share a raceway with service entrance conductors. If you've ever seen them on fire, you'd understand why - that disconnect will do nothing! Next, the house requires a disconnect at the structure regardless of whether the panel is considered a sub or a main. If this service was built prior to 2008 (I think), then the 3-wire feed to the house was code compliant. If it was built on a later code cycle then it should have been 4-conductor with the N-G bond at the disconnect.

Regardless, the panel at the house MUST have the N-G bond if it has a 3-wire feed. It is extremely dangerous without it, because the grounding system will not function and could electrify all of the grounded metal in the house.
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Old 01-24-2012, 01:52 AM   #10
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Here is a friends setup in South Dakota.

Line through the disconnect and then spliced together serving 2 structures and a well pump. The conduit going to the meter at the bottom of the pole is small so I think there are CT's in the disconnect box as well. He doesn't think it is fused until the structure panels and it is all 3 conductor. I don't know any of the bonding/grounding schemes at the pole.

Do you guys think that all 3 panels would have the neutral to equipment ground bond? I guess it would have to...right?


Subpanel WITH bonded neutral-img_3770.jpg

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Old 01-24-2012, 02:38 AM   #11
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Quote:
Originally Posted by zappa View Post
Here is a friends setup in South Dakota.

Line through the disconnect and then spliced together serving 2 structures and a well pump. The conduit going to the meter at the bottom of the pole is small so I think there are CT's in the disconnect box as well. He doesn't think it is fused until the structure panels and it is all 3 conductor. I don't know any of the bonding/grounding schemes at the pole.

Do you guys think that all 3 panels would have the neutral to equipment ground bond? I guess it would have to...right?


Attachment 44568
Zappa.,

That is the pole topper disconnect switch / transfer swith with current transfomer in there.

And with that set up it is NOT fused ( but it is fused by POCO transfomer but if any overhead drops do short it will do crazy stuff )

Also with the C/T ( Current transfomer ) meter JAMAIS ever remove the meter let the POCO deal with it. it is not the same as convental meter is.

Most farm toppers ( farm distubation set up ) I have see how the ground / bonding goes and the actual answer will varies a bit but it will always be more than one AFAIK plus the POCO may have differnet regulation related to it.

Nowdays they are start to switch over to lateral ( underground ) and moderized the set up but have proper OCPD /disconnect switch for each building and they will be running 4 conductor anyway.

Merci,
Marc
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Old 01-24-2012, 08:22 AM   #12
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Note that a typical modern residential service is 3 wire (hot, hot, messenger) from pole to house. The only overcurrent protection on the service line is the fuse that protects the pole transformer.

The situation described is the same, a 3 wire feed from the pole to the house. The fact that the "service line" to the meter and the "customer line" from the meter share the same conduit would produce no safety hazard except to the meter itself.

With one big exception. There is no appropriate overcurrent protection for your building panel downstream of the juxtaposition of service and customer lines in the shared conduit.

To fix that safety problem would eliminate grandfathering (if any) of your system. If you installed an appropriate breaker outside your building main panel then that "main" panel becomes a subpanel and needs neutral unbonded from ground. Heaven forbid you would have to put in a new building panel with main breaker inside it. If modifications are made out at the pole keeping a main disconnect out there, then you need a 4 wire feed be run from the pole to the building panel.
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Old 01-24-2012, 01:27 PM   #13
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Quote:
Originally Posted by TarheelTerp View Post

So... when are you going to fix this place up?
Hah...why do you think I'm thinking about it.

The real wow factor is that the existing service is limited by a 60 amp disconnect (breaker). How many houses today can function on only 60 amps? Probably quite a few...but you know the trend these days...amp it up!
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Old 01-24-2012, 01:40 PM   #14
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Originally Posted by AllanJ View Post
The fact that the "service line" to the meter and the "customer line" from the meter share the same conduit would produce no safety hazard except to the meter itself.

With one big exception. There is no appropriate overcurrent protection for your building panel downstream of the juxtaposition of service and customer lines in the shared conduit.
What would be protected by a post-juxtasposition OCPD, which would not be protected by a mid-span or pre-juxtasposition OCPD?

(I thought only attorneys used that word...
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Old 01-24-2012, 02:01 PM   #15
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Next, the house requires a disconnect at the structure regardless of whether the panel is considered a sub or a main.
How is this interpreted? Is the DC required to be physically attached to the structure?

In this example, the DC on the pole is located quite literally the same distance as the panel attached to the structure, from the nearest entry/exit to the structure...if that is even a consideration.

Meaning, when one exits this structure, one can either walk one direction towards the pole (and DC) or walk another direction towards the panel. Both courses of travel are the same length.

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