# Splitting a 400amp Service



## Bendigo (Dec 20, 2012)

Who would allow this method of splitting a residental 400 amp service into two (2) parallel 200 amp main disconnects?  I understand that two conductors can not be under the same lug unless specifically rated for that use.  The contractor hasn't yet provided "proof" that these lugs are rated for two conductors.  This is the first time I seen this in a meter enclosure, other installations always utilized double barreled lugs to split the service.your thoughts???

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## rnapier (Dec 20, 2012)

Last week I failed a similar installation. I can't read it but the lug has the information written on it.


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## codeworks (Dec 20, 2012)

have him pull one of the terminations apart, read the lug, see what it says, it looks like (due to "egg shape") it's a 2 conductor lug, still need to verify that though. good call


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## chris kennedy (Dec 20, 2012)

In pic two on the left side of the lug you see two lines of wire gauges stamped. The top is for single conductors and just above the washer you see 3/0. Bet there is a 2 in front of that.


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## BSSTG (Dec 20, 2012)

Greetings,

Looks like they need some bonding wires for the PVC too.

BS


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## codeworks (Dec 20, 2012)

you're joking right. how is pvc going to get energized ?


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## BSSTG (Dec 21, 2012)

codeworks said:
			
		

> you're joking right. how is pvc going to get energized ?


No I'm not joking. It's not the PVC, it's bonding between the can and disconnects. See 250.92 2011 NEC. Additionally, any pvc should have a grounding conductor anyway in all but a few rare circumstances.

BS


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## globe trekker (Dec 21, 2012)

Good catch BSSTG, on the bonding requirement!

.


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## jwelectric (Dec 21, 2012)

BSSTG said:
			
		

> No I'm not joking. It's not the PVC, it's bonding between the can and disconnects. See 250.92 2011 NEC. Additionally, any pvc should have a grounding conductor anyway in all but a few rare circumstances.BS


(1) Bonding equipment to the grounded service conductor in a manner provided in 250.8 This is done by the grounded (neutral) already being bonded in the meter can and by the main bonding jumper in the service disconnect.

To install a conductor in the PVC would be a parallel path between the meter can and the service enclosure.


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## codeworks (Dec 21, 2012)

bonding bushing with jumper only to meter can, due to reducing washers


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## BSSTG (Dec 21, 2012)

jwelectric said:
			
		

> (1) Bonding equipment to the grounded service conductor in a manner provided in 250.8 This is done by the grounded (neutral) already being bonded in the meter can and by the main bonding jumper in the service disconnect.
> 
> To install a conductor in the PVC would be a parallel path between the meter can and the service enclosure.


Only if the can is listed for the purpose. Most are not. Some are. Addtionally, by that reasoning a parallel path would be had with metal conduit. So what's the difference?

BS


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## steveray (Dec 21, 2012)

Maybe they just hadn't gotten around to pulling their grounds in yet? One from each side tied to the POCO?


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## PaulAbernathy (Dec 21, 2012)

BSSTG said:
			
		

> Only if the can is listed for the purpose. Most are not. Some are. Addtionally, by that reasoning a parallel path would be had with metal conduit. So what's the difference?BS


I would consider against making such statements. Why, because I happen to see nearly 99% of the meter socket enclosures do have this case to neutral bond. While there are obviously some meter enclosures for tenant side applications that are not I would venture to say the majority are bonded within the meter enclosure. Now this is clearly not the case in CT Cabinets but I digress.

As for the comment about whats the difference if a metal raceway is installed between the meter enclosure and service panel enclosure versus installing a conductor as Mr. Whitt spoke about previously. The answer is...agreed.....there is no difference as both could technically be a violation. However, it appears that use of a metal nipple is widely accepted (not sure why.....but it is).

Remember as you stated...only if the can is listed for that purpose. In that image you can't determine that one way or the other so suggesting it without knowing is a problem as well. How do we know that can is NOT listed for that application?


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## BSSTG (Dec 21, 2012)

PaulAbernathy said:
			
		

> Remember as you stated...only if the can is listed for that purpose. In that image you can't determine that one way or the other so suggesting it without knowing is a problem as well. How do we know that can is NOT listed for that application?


I'm just going by the research I did on this a few years back. I don't know for sure one way or the other. A lot of cans look to be bonded and reality are, but are not listed. Nevertheless, I shudder to think that of all the thousands of installs I've done over the years that were engineered with a separate grounding conductor in metal pipe was causing a problem because of parallel ground paths. A lot of folks just don't trust metal pipe for a ground anyways. I'm one of them. Throw in some flex at the termination end and it may not be compliant anyway even though it's all metal depending of course on the size, ocp and such.

Bottom line is this, if I see a PVC pipe anywhere without a ground in it, it raises a big red flag.

You folks Have a Merry Chritmas! I'm off to the country to corrupt my grandson!

BS


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## jwelectric (Dec 22, 2012)

There is a big difference in using a metal pipe for a fault current path and using a metal pipe for a parallel path for the neutral conductor.

The neutral is bonded to the meter can and also to the service disconnect enclosure and if a bonding jumper is installed in the raceway with the service conductors then all that has happened is the neutral is paralleled. This would invoke 310.10(H) and all the requirements found there.

As to using a metal raceway for an equipment grounding conductor 250.118 is the section. All the engineers in the world do not override this section no matter how dumb they are.


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## gfretwell (Dec 22, 2012)

The NFPA seems to say that we don't care about regrounding the neutral on the line side of the service disconnect.

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## jwelectric (Dec 22, 2012)

gfretwell said:
			
		

> The NFPA seems to say that we don't care about regrounding the neutral on the line side of the service disconnect.
> 
> 
> 
> ...


Are you addressing grounding or bonding, there is a big difference between the two.


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## gfretwell (Dec 22, 2012)

The neutral is grounded in the meter can by the poco and we are required to ground it again in each of the service disconnects but this picture shows it grounded in the gutter too. That makes 4 and the neutral is paralleled by the EGC all the way..


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## gfretwell (Dec 22, 2012)

BTW, in this context, until NFPA changes the green wire to an Equipment BONDING conductor I will say grounded. I know there is a push to say the only grounding conductor is the one going to the GES.


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## jwelectric (Dec 22, 2012)

What we call something has little to do with it actually is.

Ground. The earth.

Grounded (Grounding). Connected (connecting) to ground or to a conductive body that extends the ground connection.

Why would you even mention a green conductor as there is no green conductor in the illustration you posted?

In that illustration there is two main bonding jumpers in the service disconnects and two equipment bonding jumpers one to the trough and the other to the riser. These EBJs are to the isolated neutral bar in the trough and do the same thing that the screw in a single phase meter base does. See 366.60 for more information.

At to the metal raceway between the trough and the two disconnects this constitures a parallel path with the neutral and is addressed in 250.6

Should the neutral of either disconnect be lost then the metal pipe will conduct all unbalanced load for that part of the system.


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## gfretwell (Dec 22, 2012)

I just used "green wire" to imply the EGC which is actually the raceways in the picture but could be a green or bare wire.

If the neutral bar in the gutter is bonded to the raceway and the gutter itself, how is it "isolated"?

I see 6 places plus the meter where there is a solid bond between the EGC and the neutral

(3 busbar jumpers to the can and 3 bonding bushings)

I understand we are not supposed to have circuit current in EGCs, raceways and cabinets but I think NFPA has given up on that in service equipment in the line side of the disconnect since the poco is going to bond the neutral in the meter can.

They even imply this in 250.24(5)



> Load-Side Grounding Connections. A grounded conductor shall not be connected to normally non–current-carrying metal parts of equipment, to equipment grounding conductor(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article.


Then there is the above picture in the handbook

I have seen it argued both ways. I am not willing to even get into it. Just saying there are different opinions.

BTW even the road warriors will not agree in seminars. I think it was Minick who said no and Pauley who said yes but I could have that backward. I am not sure if I heard Ode say.


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## jwelectric (Dec 22, 2012)

I think you are missing the point.

The bonding that is required has nothing to do with grounding. All service equipment must be bonded to the neutral conductor.

When we use a PVC pipe between the meter and the service disconnect enclosure there is no requirement to include an Equipment Bonding Jumper in this raceway.

Should we decide to install a conductor in this raceway then that conductor is under 310 rules including 310.10(H).

If we do install an Equipment Bonding Conductor with the service entrance conductors and it is electrically connected on both ends then it is a parallel conductor that we installed and must follow 310.10(H).


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## gfretwell (Dec 22, 2012)

I am not sure where you are going with 310.10(H) (2011 for you following along)

Are you saying I can't parallel the neutral unless it is a 1/0 or above?

I do see your concern that grounding conductors and raceways become current carrying conductors if the SE neutral (between the disconnect and meter can) opens up but that is a sticky wicket any time it happens.

There are 3 scenarios.

One you do have the meter can and the service disconnect enclosure bonded via a metal raceway and the raceway is carrying the unbalanced load.

The second scenario is the two are not bonded and the unbalanced load is fed down the ground electrode conductor landed in the disconnect enclosure and you are using earth as a return. Your ground rod is a worm chaser.

The worst case is if the GEC lands in the meter can (popular some places) per 250.24(A)(1), the SE neutral opens and the unbalanced load is presented, unimpeded to every GEC and piece of equipment in the building.

Perhaps that is why some think bonding all of the service equipment together is better than worrying about some objectionable current in the SE raceway.

Actually, if you poke around with your clamp you are going to find objectionable current everywhere if look anyway. Everyone's ground system is swapping current with everyone elses.  I have a couple amps in my service neutral with the main tripped and every ground wire on a pole is carrying some current, up to almost 3 amps on my street

If we are going to we expand that discussion I suggest we open another thread.


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## jwelectric (Dec 23, 2012)

gfretwell said:
			
		

> I am not sure where you are going with 310.10(H) (2011 for you following along)Are you saying I can't parallel the neutral unless it is a 1/0 or above?


I think that you will find six rules there not just one


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## gfretwell (Dec 23, 2012)

I was just curious which one covered a wire in parallel with a raceway. Either this doesn't apply or every HFC installation in the country is a violation of several of those rules. (material, length, size etc). The references to 250.122 in (6) clearly do not apply since we use 250.66 for bonding on service conductors.


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## jwelectric (Dec 23, 2012)

gfretwell said:
			
		

> I was just curious which one covered a wire in parallel with a raceway. Either this doesn't apply or every HFC installation in the country is a violation of several of those rules. (material, length, size etc).


 I feel sure that you know the difference between a raceway and a conductor. The conductors goes into the raceway. 310.10 addresses the conductors and the conductors is what I am addressing.  





			
				gfretwell said:
			
		

> The references to 250.122 in (6) clearly do not apply since we use 250.66 for bonding on service conductors.


 Equipment grounding conductors are covered in 5 not 6. 6 covers equipment bonding conductors and any conductor on the line side of the service will be an equipment bonding conductor not an equipment grounding conductor.Althouhg a metal raceway between the meter base and the service disconnect enclosure constitures a parallel path the raceway is not a condutor as mentioned in this thread, it is a raceway, therefore not subject to 310.10 as any conductor installed in the raceway would be would be.


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## chris kennedy (Dec 23, 2012)

jwelectric said:
			
		

> the raceway is not a condutor


250.118?....


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## gfretwell (Dec 23, 2012)

> it is a raceway, therefore not subject to 310.10 as any conductor installed in the raceway would be would be.


I suppose that is why I was confused about the 310.10 reference in the first place, looking at the picture. I can see you might bring it up if there was a green/bare wire in the pipe.

I do understand there is some controversy about parallel paths but I think NFPA has avoided looking at that within the various components of service equipment, having the single path concerns only on the load side of the service disconnect. 250.24(5).


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## jwelectric (Dec 24, 2012)

The original picture is of a service to which BSSTG made the comment that an equipment grounding conductor need to be installed.

I commented that this would be in violation of 310.10(H) and Paul made a comment to the listing of the meter can and of the dangers of using metal pipe between the two.

Then you posted the Handbook picture making comments about metal pipes and the NFPA not caring about rebonding. How did you get confused?

Maybe it is because some think that a meter can is part of the service equipment. The meter be it an inline meter or a CT meter is nothing more than a cash register for the power company, a wide spot in the service conductors. It is not part of the service equipment.

We bond the equipment grounding conductors to the neutral at the same point where we have the ability to turn off all the current flow to the building.

We do not have the ability to turn off the power any other place other than at the service disconnect therefore this is where this bonding takes place.

Anything that is happening before the service disconnect is not grounding unless it is a connection to earth but instead it is bonding which is not concerned with an earth connection but instead is concerned with fault current. There is a BIG difference between the two.

As to the connection of the grounding electrode which has nothing to do with fault current, this connection can take place at the weather head or the grounding bar in the service equipment or any point in between, see 250.24.

Around here the #6 to the ground rods takes place in the meter can and the water pipe or CEE takes place in the service equipment. The neutral ties the two together.  The grounding electrode system is installed for four reasons and fault current is not found in that section of the codes, see 250.4(A)(1).

Merry Christmas


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## gfretwell (Dec 24, 2012)

I think we agree and we are just having a semantic discussion.


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## BSSTG (Dec 26, 2012)

Greetings,

Well I stand corrected. In doing some digging I ran across this article from EC&M. It states that bonding is not required when the conduit from the meter can to the panel is PVC. That said, if the conduit is metal then it is required to be bonded with groundling bushings or locknuts around concentric KO"s and so forth. They are saying that it's ok for the meter can to be bonded via the neutral with nothing else required with the PVC. I suspect the reasoning for this is that if a fault were to occur in metal conduit then it would need be bonded since it will carry current. If it were to have a fault in PVC there would be no need to be bonded as the pipe wouldn't be energized.

This is contrary to the research I did a few years back when this very subject came up. What I found was that not all meter cans were considered bonded when the neutral was made up with no additional bonding when PVC was the load side conduit. I also looked at quite a few meter cans and it was iffy for them to be self bonding as the screws did not appear to make up 2 full threads and did not look to comply with 250.8 otherwise. Meter can listings were dubious as well.

This is not an issue where I'm at as the electical provider will not turn on power without direct grounding connections in the meter can to the GEC. Additionally, our local ordinance requires ground wires in all conduits regardless. I don't know who but it in there but it takes a lot of guesswork out of the grounding/bonding question.

Here is the link that I found helpful.

Grounding and Bonding

Happy New Year!

BSSTG


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## gfretwell (Dec 26, 2012)

I suspect PoCos started bonding in the can when the PVC SE raceway showed up. That avoids all of the parallel neutral thing if someone ran a green wire.


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## codeworks (Dec 27, 2012)

bs, what month, year was that in. i've got a bunch of 'em, i'd like to read that (again probably)


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## codeworks (Dec 27, 2012)

duh, you provided a link,


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## BSSTG (Dec 27, 2012)

codeworks said:
			
		

> bs, what month, year was that in. i've got a bunch of 'em, i'd like to read that (again probably)


June 21, 2011


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## BSSTG (Dec 27, 2012)

codeworks said:
			
		

> duh, you provided a link,


Is it not working?

BS


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