GEC entering panel

[peter d]

You do realize that section was talking about ferrous metal conduit being used to protect the GEC.

He is just throwing everything at the wall to see what sticks at this point.

 

[peter d]

I'm trying to keep up with the gist of where this thread is going and I'm not sure if it matters where the GEC gets terminated. We used to be able to land a GEC inside the meter pan here in NJ but many EI's now will not allow it citing that it is not "serviceable" once the POCO locks the meter pan. So, all grounding wiring has to be done inside the panel with the first or main over-current device. Now we're back to the green ground screw as being the only thing bonding the neutral bar to the cabinet (assuming everything upstream was either PVC or SE cable).

We terminate in the meter socket whenever possible. Our poco allows it and most inspectors don't have an issue with it, but some do. :roll:

The green bonding screw is factory made for that purpose, so I'm not sure what the issue it? :huh:

 

[roger]

From: Romex Jockey Electric
Sent: Monday, December 18, 2017 4:10 PM
To: Rick Holbrook Milbank rep
Subject: Technical Question for you



Dear Rick & Cathy Holbrook
I'm a Vermont electrician with a question about Milbank meters and/or enclosures I'm hoping you can help me with.

It would appear there is a dispute in just what the 1/4" knockouts on the bottom of your meters are really for

Some say it's for the GEC (Grounding Electrode conductor)* , usually a bare #6 or #4 copper wire to simply run through

However, we are finding this is not to code, the* NEC passage(s) below being applicable

Can you unfuzz me please? Thank you for your time
~*Vermont Electrician

From: Rick Holbrook
Sent: Tuesday, December 19, 2017 2:04 PM
Subject: FW: Technical Question for you


Hi Steve,
The ¼” KO’s are for water drainage only.

Steve, just quit using Milbank if they don't have any real tech support and use SQ D where you can get good information.

and

https://www.schneider-electric.us/e...cale=en_US&searchid=1513601844104#__highlight


Roger

 

[goldstar]

The green bonding screw is factory made for that purpose, so I'm not sure what the issue it? :huh:

I'm not trying to make a big issue out of this but, as I mentioned, I have burnt one of these out of the panel before. Even though the screw is factory provided and put through UL, if you stop and think about the number of threads on the screw and how much of it's surface comes in contact with the panel itself it seems clear to me that it is capable of clearing one major fault, as in my case. I understand your point and there's no point in prolonging this part of the thread. I was just trying to make a case for my squeeze connector (extra grounding) method.

 

[infinity]

I was just trying to make a case for my squeeze connector (extra grounding) method.

It certainly wouldn't hurt to do it that way but one poster stated that if a squeeze connector were used then it would be required to strip the insulation off of an insulated GEC, that is not required by the NEC. Good idea for the reason that you've mentioned but good ideas are not requirements (I know that you know that) .

Most of this is a non-issue, GEC's have been run through those small KO's for decades without any issues. If the small KO scenario were so dangerous by now we would be required to use a Kenny clamp or some similar fitting.

IMO the NEC can do a better job of outlining what is and isn't required. I can use the small KO and run the GEC right through, if I knock out a 3/4" KO can I do the same?

 

[goldstar]

It certainly wouldn't hurt to do it that way but one poster stated that if a squeeze connector were used then it would be required to strip the insulation off of an insulated GEC, that is not required by the NEC. Good idea for the reason that you've mentioned but good ideas are not requirements (I know that you know that) .

Most of this is a non-issue, GEC's have been run through those small KO's for decades without any issues. If the small KO scenario were so dangerous by now we would be required to use a Kenny clamp or some similar fitting.

IMO the NEC can do a better job of outlining what is and isn't required. I can use the small KO and run the GEC right through, if I knock out a 3/4" KO can I do the same?

Agreed. Maybe the panel manufacturers can come up with a better idea, although it would seem to me that they would do whatever little it takes to get by with whatever they've already designed

 

[romex jockey]

Because any given manufacturer points out a 1/4" GEC entry does not mean we can forgo 312.5(A)

That it is an KO for 'entry' , means we shall use an approved means to enter the conductor

approved means listed,rated. the '17 has upped the ante' for this

ergo, one can use the entry pointed out as long as 312.5(A) is addressed

yes there are exceptions for flying conductors to enter without said means elsewhere

I see no exception to 312.5(A)

thx

~RJ~

 

[peter d]

Because any given manufacturer points out a 1/4" GEC entry does not mean we can forgo 312.5(A)

That it is an KO for 'entry' , means we shall use an approved means to enter the conductor

approved means listed,rated. the '17 has upped the ante' for this

ergo, one can use the entry pointed out as long as 312.5(A) is addressed

yes there are exceptions for flying conductors to enter without said means elsewhere

I see no exception to 312.5(A)

thx

~RJ~

That section doesn't apply. How does a conductor enter to a closed opening? You're not reading the words, you're forcing your own interpretation.

 

[infinity]

If the conductor fills most of the hole in many jurisdictions that is the way that it's done and it's closed in an approved manner.

312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures.
Conductors entering enclosures within the scope of this article
shall be protected from abrasion and shall comply with
312.5(A) through (C).
(A) Openings to Be Closed. Openings through which
conductors enter shall be closed in an approved manner.

 

[kwired]

We terminate in the meter socket whenever possible. Our poco allows it and most inspectors don't have an issue with it, but some do. :roll:

The green bonding screw is factory made for that purpose, so I'm not sure what the issue it? :huh:

I'm not trying to make a big issue out of this but, as I mentioned, I have burnt one of these out of the panel before. Even though the screw is factory provided and put through UL, if you stop and think about the number of threads on the screw and how much of it's surface comes in contact with the panel itself it seems clear to me that it is capable of clearing one major fault, as in my case. I understand your point and there's no point in prolonging this part of the thread. I was just trying to make a case for my squeeze connector (extra grounding) method.

The neutral terminal in the meter socket is attached to the cabinet with a screw(s).

Burning that bonding screw out of the panel - I can see possible, Lightning event - I bet there was more damage then just at that bonding screw, failure of an overcurrent device to open a ground fault - either OCPD malfunction or improper application is my top of the list of what went wrong here, maybe followed by bonding screw not properly tightened. GEC resistance shouldn't matter, majority of such fault current should be coming into this on the EGC and returning to source via grounded service conductor, should be low enough overall impedance that fault current will be high and will cause rapid operation of the OCPD, for some reason you did have enough resistance to limit fault current or maybe had a fault on a service conductor.

 

[goldstar]

The neutral terminal in the meter socket is attached to the cabinet with a screw(s).

Burning that bonding screw out of the panel - I can see possible, Lightning event - I bet there was more damage then just at that bonding screw, failure of an overcurrent device to open a ground fault - either OCPD malfunction or improper application is my top of the list of what went wrong here, maybe followed by bonding screw not properly tightened. GEC resistance shouldn't matter, majority of such fault current should be coming into this on the EGC and returning to source via grounded service conductor, should be low enough overall impedance that fault current will be high and will cause rapid operation of the OCPD, for some reason you did have enough resistance to limit fault current or maybe had a fault on a service conductor.

Sorry, I forgot to mention that the main 200A breaker did trip when that incident happened. The green screw was no longer able to function as a means to bond the neutral bar to the cabinet. I ended up using (2) self tapping screws for that purpose. It was a Square D Homeline panel if that matters.

Yes and BTW, several of the slots in the panel where the wire hit and where the breakers plug in had to be filed down to remove the burn marks so that the breakers would fit. As I've said many times in past posts "You have to pay for your education". Needless to say I won't do that again and I'm thankful that I didn't get injured from the arc flash. :thumbsup:

 

[kwired]

Sorry, I forgot to mention that the main 200A breaker did trip when that incident happened. The green screw was no longer able to function as a means to bond the neutral bar to the cabinet. I ended up using (2) self tapping screws for that purpose. It was a Square D Homeline panel if that matters.

Yes and BTW, several of the slots in the panel where the wire hit and where the breakers plug in had to be filed down to remove the burn marks so that the breakers would fit. As I've said many times in past posts "You have to pay for your education". Needless to say I won't do that again and I'm thankful that I didn't get injured from the arc flash. :thumbsup:

Panel bus probably should have been replaced also in that situation. Homeline bus is tin plated aluminum, filing off anything leaves you with just aluminum wherever you do this.

self tapping screws - in particular a coarse threaded screw - leaves you with less thread contact in the metal then a machine thread screw - plus the factory bonding screw location is machined to make thicker wall at the point the screw is installed to make more thread contact depth. Add to that if the bonding screw wasn't tight enough you have additional arcing at that weak connection point(s)

 

[romex jockey]

If the conductor fills most of the hole in many jurisdictions that is the way that it's done and it's closed in an approved manner.

Then we can ask Milbank manufacturing etc, if it is in fact listed as such



>>>

250.8 Connection of Grounding and Bonding Equipment.
(A) Permitted Methods. Equipment grounding conductors,
grounding electrode conductors, and bonding jumpers shall be
connected by one or more of the following means:
(1) Listed pressure connectors
(2) Terminal bars
(3) Pressure connectors listed as grounding and bonding
equipment
(4) Exothermic welding process
(5) Machine screw-type fasteners that engage not less than
two threads or are secured with a nut
(6) Thread-forming machine screws that engage not less than
two threads in the enclosure
(7) Connections that are part of a listed assembly
(8) Other listed means




~RJ~

 

[infinity]

Then we can ask Milbank manufacturing etc, if it is in fact listed as such
~RJ~

If Milbank want to say that the small KO's in their equipment aren't listed for GEC's that fine but as Roger pointed out Sq D and likely other manufacturers specify in their literature that the small KO's are designed for GEC entry.

 

[romex jockey]

If Milbank want to say that the small KO's in their equipment aren't listed for GEC's that fine but as Roger pointed out Sq D and likely other manufacturers specify in their literature that the small KO's are designed for GEC entry.

Then any given manufacturer rep claims vs. what the product is listed for is in dispute here then Mr Infinity

Here's my closest Milbank rep's response>>>


From: Rick Holbrook
Sent: Tuesday, December 19, 2017 2:04 PM
Subject: FW: Technical Question for you

The ¼” KO’s are for water drainage only.

Does his 'opinion' trump 110.3(B) ?

~RJ~

 

[infinity]

Then any given manufacturer rep claims vs. what the product is listed for is in dispute here then Mr Infinity

Here's my closest Milbank rep's response>>>


From: Rick Holbrook
Sent: Tuesday, December 19, 2017 2:04 PM
Subject: FW: Technical Question for you

The ¼” KO’s are for water drainage only.

Does his 'opinion' trump 110.3(B) ?

~RJ~

Is that an opinion or a fact? Most inspectors around here are not going to care if they call it a GEC KO or a drainage KO. House A has Sq D Meter pan next door house B has Milbank, does the inspector care if each uses that KO for the GEC?

 

[kwired]

Is that an opinion or a fact? Most inspectors around here are not going to care if they call it a GEC KO or a drainage KO. House A has Sq D Meter pan next door house B has Milbank, does the inspector care if each uses that KO for the GEC?

My question also. I have seen many 3R cabinets that already have holes that I would assume are for drainage in the bottom corners (and no option as to whether you want to knock them out either - the hole is already there)plus a small KO that many often use for GEC's. Pretty much all Square D QO and Homeline 3R type loadcenters are like this.

 

[peter d]

Then we can ask Milbank manufacturing etc, if it is in fact listed as such



>>>

250.8 Connection of Grounding and Bonding Equipment.
(A) Permitted Methods. Equipment grounding conductors,
grounding electrode conductors, and bonding jumpers shall be
connected by one or more of the following means:
(1) Listed pressure connectors
(2) Terminal bars
(3) Pressure connectors listed as grounding and bonding
equipment
(4) Exothermic welding process
(5) Machine screw-type fasteners that engage not less than
two threads or are secured with a nut
(6) Thread-forming machine screws that engage not less than
two threads in the enclosure
(7) Connections that are part of a listed assembly
(8) Other listed means




~RJ~

That article doesn't apply since a GEC passing through an opening is not a "connection". That section is addressing things like connecting the GEC to a ground rod via a listed acorn clamp, or connecting it to a bus bar, lug, etc. You really need to brush up on Charlie's Rule for reading the NEC because you're falling on your face right now.

 

[infinity]

My question also. I have seen many 3R cabinets that already have holes that I would assume are for drainage in the bottom corners (and no option as to whether you want to knock them out either - the hole is already there)plus a small KO that many often use for GEC's. Pretty much all Square D QO and Homeline 3R type loadcenters are like this.

I'm not the best guy to ask about 3R listings but I would assume that for 3R meter enclosures they are already designed to drain without removing any KO's. If you look at a Milbank meter enclosure they have slots at the front lower corners seemingly for this purpose.

 

[kwired]

That article doesn't apply since a GEC passing through an opening is not a "connection". That section is addressing things like connecting the GEC to a ground rod via a listed acorn clamp, or connecting it to a bus bar, lug, etc. You really need to brush up on Charlie's Rule for reading the NEC because you're falling on your face right now.

My first thought was that section didn't apply, wasn't coming up with a way to word a response right away though, but you are right passing through a hole is not the same thing as a connection.