neutral

[Sparky32297]

question I have a new 200 amp service to replace burnt up pole top disconnect . I came down to the meter disconnect combo with PVC -120/240 single phase - with 3 wires - going back up the pole with PVC, do I need to include the neutral in this other PVC or can I just run the ungrounded conductors and the equipment ground wire up this pipe

 

[raider1]

Do you need a neutral after the service disconnecting means?

If a neutral is not required then you don't need to bring it any farther than the service disconnecting means.

Chris

 

[erickench]

What exactly do you mean by "other PVC"?

 

[augie47]

I think I understand as I see it on occassion here. A meter/disco on the POCO pole with line and load conduits. In essence the question that arises here is can the neutral be spliced at the top of the conduits (from POCO aerial to load side aerial) without being routed thru the two conduits.
(an appropriate sized bonding conductor is insatlled to bond the meter)

If that is the situation my answer would be that according to 300.3(B), no, the neutral would need to run thru both conduits. That said, I see it installed the other way often.

 

[erickench]

Well the best way I could answer your question is by saying that if you do not run a neutral through the feeder then all your loads will be 240 Volts. No 120 V.

 

[Sparky32297]

I think I understand as I see it on occassion here. A meter/disco on the POCO pole with line and load conduits. In essence the question that arises here is can the neutral be spliced at the top of the conduits (from POCO aerial to load side aerial) without being routed thru the two conduits.
(an appropriate sized bonding conductor is insatlled to bond the meter)

If that is the situation my answer would be that according to 300.3(B), no, the neutral would need to run thru both conduits. That said, I see it installed the other way often.

Sorry about the lack of info

this is exactly what I have - the line conduit coming down the pole has the full size neutral and the load conduit going back up the pole has no neutral installed in it and all the neutrals are splices at the top of the pole

I looked at this and it just looked wrong to me

thanks

 

[augie47]

as stated, my opinion is that without pulling the neutral thru the both conduits it is a Code violation of 300.3(B).
It has been my experiece that in this situatuation the "violation" case it is often "overlooked'

 

[erickench]

Augie, I don't think NEC 300.3(B) applies in this case. That particular NEC section is concerned with reducing inductance by running all the conductors of the same circuit in the same raceway. The feeder is on the load side of the disconnect and there is no neutral which means the currents running on each of the ungrounded conductors are equal to each other. The inductance caused by each ungrounded conductor cancel each other out. If the neutral was carrying load and run separately from the raceway containing the ungrounded conductors then you would have a problem.

 

[Sparky32297]

Augie, I don't think NEC 300.3(B) applies in this case. That particular NEC section is concerned with reducing inductance by running all the conductors of the same circuit in the same raceway. The feeder is on the load side of the disconnect and there is no neutral which means the currents running on each of the ungrounded conductors are equal to each other. The inductance caused by each ungrounded conductor cancel each other out. If the neutral was carrying load and run separately from the raceway containing the ungrounded conductors then you would have a problem.

This is what throws me - the netral is carrying a load but it is all spliced at the top of the pole so you can have an unbalanced load in the second pipe with the feeders running up the pole. This might be a hard concept to see if you have never seen a pole top. It is very common around here.

 

[augie47]

Augie, I don't think NEC 300.3(B) applies in this case. That particular NEC section is concerned with reducing inductance by running all the conductors of the same circuit in the same raceway. The feeder is on the load side of the disconnect and there is no neutral which means the currents running on each of the ungrounded conductors are equal to each other. The inductance caused by each ungrounded conductor cancel each other out. If the neutral was carrying load and run separately from the raceway containing the ungrounded conductors then you would have a problem.

Not having your knowledge I would not enter into the inductance conversation, however, despite your logic, I don't see any exception in 300.3(B) that allows the install he describes.
Your explanation may explain why the rule is often overlooked but it seems to me that it is still a technical violation.

 

[nakulak]

I'm having a hard time wrapping my head around this, as to how serious a violation it is. I guess it would be the same as running a neutral from a branch circuit directly to the incoming service neutral - in other words, you are bypassing the main and the main bonding jumper. Is this a hazard ? Well, electrically its still connected and in terms of resistance probably impossible to detect. The question is, does it represent some improbably hazard ? I can't think of a condition where it would make a difference as to the operation of the main or the circuit conductors or the circuit. I realize it's a violation, but can anyone point out how it could be a hazard ? (however unlikely)