GEC passing through panels

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Cletis

Senior Member
Location
OH
In 250.64 does anyone know why they disallowed in 2011 (the reasoning) running the main GEC from water main into one panel that passes through to a second or more panel as a continuous run ??
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
Sorry but I do not see where this method (if sized correctly) was not permitted in the 2011 NEC. If you are working in 250.64 then the guess is you are working with multiple service disconnects. A daisy chain approach is acceptable as long as it is sized properly. Maybe you can be a little more detailed on what you as asking in case I am missing something here. I purely looked in 250.64 as that was where your reference was based.
 

david

Senior Member
Location
Pennsylvania
Sorry but I do not see where this method (if sized correctly) was not permitted in the 2011 NEC. If you are working in 250.64 then the guess is you are working with multiple service disconnects. A daisy chain approach is acceptable as long as it is sized properly. Maybe you can be a little more detailed on what you as asking in case I am missing something here. I purely looked in 250.64 as that was where your reference was based.

Maybe I am not understanding this section of the code. Could you point me to where daisy chaining from one panels bus to another panels was is an approved method. Secondly why would you involve the hole chain of panels? Why would you not make taps from each panel to the grounding electrode conductor?
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
Maybe I am not understanding this section of the code. Could you point me to where daisy chaining from one panels bus to another panels was is an approved method. Secondly why would you involve the hole chain of panels? Why would you not make taps from each panel to the grounding electrode conductor?

Never said it was the preferred method just not prohibited.

Look at (D)(2), just his unique approach to providing that individual grounding electrode conductor between disconnects. He stated it was unbroken to add to some additional function (not sure how practical it is) but it would serve the purpose.
 

david

Senior Member
Location
Pennsylvania
Never said it was the preferred method just not prohibited.

Look at (D)(2), just his unique approach to providing that individual grounding electrode conductor between disconnects. He stated it was unbroken to add to some additional function (not sure how practical it is) but it would serve the purpose.

250.64(D)
? Taps, from each individual disconnect
? Individual grounding electrode conductors from each service disconnect
? Common location on the supply side of the service disconnects
I the common location is on the supply side of the service disconnects
I am still not seeing where the method of daisy chaining from individual panels bus-bars is specified in this section

When I did electrical work I was always taught not to do it that way and now looking at others installations I am not sure how guys conclude that this method is specified in that section of the code
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
250.64(D)
? Taps, from each individual disconnect
? Individual grounding electrode conductors from each service disconnect
? Common location on the supply side of the service disconnects
I the common location is on the supply side of the service disconnects
I am still not seeing where the method of daisy chaining from individual panels bus-bars is specified in this section

When I did electrical work I was always taught not to do it that way and now looking at others installations I am not sure how guys conclude that this method is specified in that section of the code

Again never said it was the preferred method. however, it is an individual grounding electrode conductor from each disconnect using a continuous unbroken GEC. Too complicated to actual do with the bending radius at the terminals but is possible.

I don't have an image for you....but their is an example in the 2011 NEC Handbook by McPartland/Hartwell/McPartland thats shows it, again i would not do it....too complicated to make it happen.
 

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david

Senior Member
Location
Pennsylvania
Again never said it was the preferred method. however, it is an individual grounding electrode conductor from each disconnect using a continuous unbroken GEC. Too complicated to actual do with the bending radius at the terminals but is possible.

I don't have an image for you....but their is an example in the 2011 NEC Handbook by McPartland/Hartwell/McPartland thats shows it, again i would not do it....too complicated to make it happen.

Doesn?t the section basically direct a connection from the individual service disconnects to a point defined as the grounding electrode system.
Is the neutral bus of the next panel part of the grounding electrode system?

I have the hand book I will take a look at the illustration
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
The only argument I have always really had about this is the fact that if one service disconnect is removed it messes up the path. however, as one AHJ told me one time, if they come and mess it up, we will make them put it back right. Provided they pull a permit.
 

david

Senior Member
Location
Pennsylvania
see image in post #6

Ok I see the image you posted I read the handbook.
I do not see how the actual code text supports the illustration.
The section is titled individual grounding electrode conductors. The text says to go from point A to Point B.
From the individual disconnects grounded conductor to the grounding electrode system,
I do not read that as passing through the next panels buss on way to the grounding electrode system
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
Ok I see the image you posted I read the handbook.
I do not see how the actual code text supports the illustration.
The section is titled individual grounding electrode conductors. The text says to go from point A to Point B.
From the individual disconnects grounded conductor to the grounding electrode system,
I do not read that as passing through the next panels buss on way to the grounding electrode system

Are each of the GEC's running unbroken through each enclosure?...if you take away the enclosure are they each not a single GEC being installed to the GES. Like I said, not a real practical way to install it but it would meet the intent and I do not think lightning cares either way.
 

Cletis

Senior Member
Location
OH
Again never said it was the preferred method. however, it is an individual grounding electrode conductor from each disconnect using a continuous unbroken GEC. Too complicated to actual do with the bending radius at the terminals but is possible.

I don't have an image for you....but their is an example in the 2011 NEC Handbook by McPartland/Hartwell/McPartland thats shows it, again i would not do it....too complicated to make it happen.

That's how we used to do it. We just used lay in lugs and 1/2" romex connectors to go in/out each panel. Actually, it was quite easy and no bending radius problem. Now, our inspectors won't let us do it that way anymore around here
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
That's how we used to do it. We just used lay in lugs and 1/2" romex connectors to go in/out each panel. Actually, it was quite easy and no bending radius problem. Now, our inspectors won't let us do it that way anymore around here

While I might not accept the 1/2" NM-B connectors(but Im not an AHJ anymore so have at it)....as they are not listed for that application I would ask them what section they are referencing that they would not let you do it, if thats a method you happen to like doing.
 

david

Senior Member
Location
Pennsylvania
Are each of the GEC's running unbroken through each enclosure?.

yes

.if you take away the enclosure are they each not a single GEC being installed to the GES. Like I said, not a real practical way to install it but it would meet the intent and I do not think lightning cares either way.

No

And besides that is not what the section says, It says from each of the individual enclosures a grounding electrode conductor from each of the grounded conductors to the grounding electrode system

That becomes more clear in the rest of the section when it tells you how to size the grounding electrode conductor going from each of the enclosures grounded conductor to the grounding electrode system. No where in that section does it tell you to size the grounding electrode conductor as a common grounding electrode conductor
 

david

Senior Member
Location
Pennsylvania
I would ask them what section they are referencing that they would not let you do it, if that?s a method you happen to like doing.

The section is 250.64

The section says shall be installed as specified

This method is not specified in this section of the code, and I would point out in each section it is specific in how to size the grounding electrode conductor.

If you daisy chain the panels together you would have to interpolate from other sections to determine a method of sizing this common grounding electrode conductor you are using to tie the buses together and continue to the grounding electrode system.

The daisy chain method does not have individual grounding electrode conductors, but rather a common grounding electrode conductor, a common grounding electrode conductors method, according to 250.64 originate at a point on the supply side of the multiple service disconnects.
 

hurk27

Senior Member
In 250.64 does anyone know why they disallowed in 2011 (the reasoning) running the main GEC from water main into one panel that passes through to a second or more panel as a continuous run ??

First you haven't stated if these are all service panels like on a multi-occupancy apartment building or a strip mall? or are we talking about running through sub panels and the raceway back to the main service? both will have different requirements that may make or break this method.

The main one that jumps out at me is the requirement in 250.64(E) that would require us to bond every raceway at each cabinet, junction box that encloses the GEC, also with the fact the GEC has to be continuous it would make the above very hard to do in some cases.

From lightning stand point I myself would not want to invite lightning to flashover to circuit conductors along the way, so in no way would I use this method.
 

Cletis

Senior Member
Location
OH
First you haven't stated if these are all service panels like on a multi-occupancy apartment building or a strip mall? or are we talking about running through sub panels and the raceway back to the main service? both will have different requirements that may make or break this method.

The main one that jumps out at me is the requirement in 250.64(E) that would require us to bond every raceway at each cabinet, junction box that encloses the GEC, also with the fact the GEC has to be continuous it would make the above very hard to do in some cases.

From lightning stand point I myself would not want to invite lightning to flashover to circuit conductors along the way, so in no way would I use this method.

In this case, I'm just talking about your standard apartment setup. Say a 320/400 amp service going to 3 - 150 amp main breaker panels side by side grouped together or something similar. We have done them this way since the 80's and this is first time I got tagged on doing it that way. We ended up just making taps below with split bolts to pass inspection and he was fine with that. Not really a big deal time or effort so I didn't even put up a fight. Just curious if he is making something up or not.
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
Well you all better let McPartland and Hartwell know their 2014 Handbook is wrong..lol...I posted their picture from their book. As for me, I find it unorthodox but compliant good news is I'm not an AHJ so have at it.
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
First you haven't stated if these are all service panels like on a multi-occupancy apartment building or a strip mall? or are we talking about running through sub panels and the raceway back to the main service? both will have different requirements that may make or break this method.

The main one that jumps out at me is the requirement in 250.64(E) that would require us to bond every raceway at each cabinet, junction box that encloses the GEC, also with the fact the GEC has to be continuous it would make the above very hard to do in some cases.

From lightning stand point I myself would not want to invite lightning to flashover to circuit conductors along the way, so in no way would I use this method.

"(1) General. Ferrous metal raceways and enclosures for grounding electrode conductors shall be electrically con- tinuous from the point of attachment to cabinets or equipment to the grounding electrode and shall be securely flattened to the ground clamp or ?tting. Ferrous metal raceways and enclosures shall be bonded at each end of the raceway or enclosure to the grounding electrode or grounding electrode conductor. Nonferrous metal raceways and enclosures shall not be required to be electrically continuous."

This is not an impossible task. As for the lightning, everything would be at the same potential so not sure why that would be a concern for flash over. Again, not something I care to condone but it is possible and that's why I believe the graphic was generated.
 

Cletis

Senior Member
Location
OH
Typically, I just buy a few of these lay in lugs, run typically a #4 Cu conductor from water main all the way to first panel and in/out of each panel. 2 parts, quick and easy. Now, it's against code all of a sudden (or is it ? )

I'd love to get to the bottom of this. I'd rather go back to my method for last 30 years.
 

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