Neutral to all sub-panels

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N2deepsky

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This is my first time, be gentle.

Is a neutral required to be ran to all sub-panels?

I?m looking at a 240 volt single phase service that has a sub-panel fed from it. The sub-panel?s only loads are two 240 volt circuits. Given that an equipment grounding conductor is required, must a grounded conductor also be ran to it?

200.2 is telling me ?all premises wiring systems shall have a grounded conductor?? I?m not able to find in any of the exceptions or prohibitions listed, a way not to require the contractor to install one.

What are your thoughts.
 
N2deepsky said:
This is my first time, be gentle.

Is a neutral required to be ran to all sub-panels?

What are your thoughts.
Click to expand...

A neutral is only required if there is a neutral load needed. If all you have is 220 volt circuits with no neutrals then you don't need it, however I would suggest putting one there just in case.
 
N2deepsky said:
200.2 is telling me “all premises wiring systems shall have a grounded conductor…”
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A system grounded conductor must be run to the premises main disconnect for the purposes of grounding and bonding (and operation of ground-fault equipment), but beyond that, only where needed by the loads.
 
I'll agree it is not required and also a good idea (looking forward) to add the 4th conductor...but I'm not paying for it ;) (see below)
 
I want to thank all of you who have responded. My dilemma is, I?m the no good sob (AHJ) who is making the poor contractor spend more of his profit and time to install a wire that both he and I agree is never going to be used. But I can?t get past 200.2. I need a code article to justify my position. As it is at this point I believe it should have one.

In a round about way I see 240.24(C) as saying the grounded conductor must be ran to each service disconnect, period, end of story. But this article pertains to grounding and not grounded conductors.

Thanks again
 
I don't think 200.2 applies to every single point on the premices wireing system. In that case, you would have to run a neutral with every 240v circuit. JMO.
 
The title of Article 200 is "Use and Identification of Grounded Conductors." Meaning that if you are going to use a grounded conductors here are the rules. If there isn't a neutral ran to the panel then you can't use article 200. If you had to use a grounded conductor on all panels why would there be a 240V delta panel or 208Y or 240 single phase panel?
On a side note and as an electrical engineer who does a lot of existing design changes, it drives me crazy when there is an existing pool pump on a 16 circuit panel and the customer wants to add a small 120V load and the contractor didn't run a small neutral. You don't have to full size it, just put in a #12 just for the future.
 
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N2deepsky said:
But I can?t get past 200.2. I need a code article to justify my position. As it is at this point I believe it should have one.

In a round about way I see 240.24(C) as saying the grounded conductor must be ran to each service disconnect, period, end of story. But this article pertains to grounding and not grounded conductors.

Thanks again
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Firstly, try to get past 200.2. There is a neutral on the premise. This is really no different than running a 220 branch circuit to well. You wouldn't ask the electrician to run a neutral, would you???? If the panel is only 220 volt circuits what is the big deal. It is grounded and if someone needs a neutral the main panel box is always available. I still think it would be nice for future possibilities but if you don't see that as a reality then why pursue it. It's legal and safe.

article 240.24(C) must be a typo on your part. It has nothing to do with grounded conductors-- unless you have a different code book.
 
AS LONG AS there was a neutral present for the "premises wiring system" ie) at the service panel, that aspect of 200.2 has been satisfied.

You are allowed to install circuits without a neutral for line-to-line loads, the same thinking is applied to feeders and by extension, sub-panels.

215.7 is your reference for feeder circuits that you seek. It is listed in 200.2 as one of the instances where a neutral is not required:

215.7 Ungrounded Conductors Tapped from Grounded Systems.... ac circuits of two or more ungrounded conductors shall be permitted to be tapped from the ungrounded conductors of circuits having a grounded neutral conductor. Switching devices in each tapped circuit shall have a pole in each ungrounded conductor.
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Bjenks said:
On a side note and as an electrical engineer who does a lot of existing design changes, it drives me crazy when there is an existing pool pump on a 16 circuit panel and the customer wants to add a small 120V load and the contractor didn't run a small neutral. You don't have to full size it, just put in a #12 just for the future.
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That was true with the 2002 NEC, but a change in the 2005 NEC requires a grounded conductor sized per 250.122. This proposal was based on the rare premises that a hot to neutral short to a #12 neutral would burn the neutral up before the CPD clears.
See 215.2 A 1
 
Tom,
I am familiar with the neutral sizing for Service Entrance because there isn't a grounding conductor, however I thank you for pointing out 215.2 as I never noticed that change. Luckily I never size my feeders less than 2 sizes off the ungrounded conductor. However in this case I would have been incorrect.
 
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N2deepsky said:
This is my first time, be gentle.

Is a neutral required to be ran to all sub-panels?

I’m looking at a 240 volt single phase service that has a sub-panel fed from it. The sub-panel’s only loads are two 240 volt circuits. Given that an equipment grounding conductor is required, must a grounded conductor also be ran to it?

200.2 is telling me “all premises wiring systems shall have a grounded conductor…” I’m not able to find in any of the exceptions or prohibitions listed, a way not to require the contractor to install one.

What are your thoughts.
Click to expand...
I think what we may be missing is that this is a subpanel so most of us are correct in saying that you don't need a nuetral but these are the things the customer and/or designer should consider. They may regret not running a grounded conductor later and usually do.
 
tom baker said:
That was true with the 2002 NEC, but a change in the 2005 NEC requires a grounded conductor sized per 250.122. This proposal was based on the rare premises that a hot to neutral short to a #12 neutral would burn the neutral up before the CPD clears.
See 215.2 A 1
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Sorry Tom as usual i submitted my post before seeing yours. I do have a question, however. 215.2 A 1 refers to feeders. Since this is a subpanel, this rule shouldn't apply allowing you to leave out the nuetral to the subpanbel. Since this is a branch circuit, I don't see anything in the NEC requiring the grounded conducter. Is this correct?
 
Once again thanks

Dennis Alwon you are correct it is a typo. I should have said 200.3 tells me if a grounded conductor is present in the premises wiring the service must also have one. 250.24(C) is saying to me if a neutral is present in the supply system it must be ran to each service disconnect and bonded to it.

Kbsparky I?m going to have to work on this one. To me, taps are conductors that are not protected where they receive their power but have their overcurrent protection at the load end of the conductors.

240.2 Definitions.

Tap Conductors. As used in this article, a tap conductor is defined as a conductor, other than service conductor, that has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected as described elsewhere in 240.4.

In my case the feeder that supplies the panel originates at a circuit breaker.

Anyway, common sense will sometimes win.
 
Monkey to answer your question, no. The branch circuit ran to the condensing unit serves that piece of equipment and the code requires there to be a disconnect within sight of it.
 
N2deepsky said:
...Kbsparky I?m going to have to work on this one. To me, taps are conductors that are not protected where they receive their power but have their overcurrent protection at the load end of the conductors.

240.2 Definitions.

Tap Conductors. As used in this article, a tap conductor is defined as a conductor, other than service conductor, that has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected as described elsewhere in 240.4.

In my case the feeder that supplies the panel originates at a circuit breaker.....
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OK, take a look at your quote: As used in this article... you have quoted a definition from article 240. The definition given in 240.2 only applies to that particular article.

My quote was from article 215, and there was no corresponding definition or cross reference to 240 for the term tap given. Therefore, the definition given in article 240 does not apply to the term's use in 215. There is no definition of the term given in the list in article 100, either.

Since there is no official definition of the term elsewhere in the Code, you are free to apply its use to anything else that would resemble a tap: A circuit breaker, switch, bug, panel buss, etc. :grin:
 
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