215.2(A)(2)
- Thread starter m sleem
- Start date
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- Connecticut
- Occupation
- Engineer
No, that does not apply to branch circuits.
As far as I know, the only permitted reduction for a branch circuit neutral is in 210.19(A)(3) Ex. No. 2. If there are other permitted reductions, hopefully someone will point them out.
But it refers to ungrounded conductor not grounding conductor.
- Location
- Connecticut
- Occupation
- Engineer
It refers to the neutral (grounded) conductor.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
210 and it's subsections are for branch circuits
215 and it's subsections are for feeders
230 and it's subsections are for services.
Unless you have a situation that refers you elsewhere that is the general rules.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
(A)(3) is for ranges and cooking appliances.
(A)(1) is the general rule and only says they need to be sized per the load to be served.
(A)(2) is for circuits with multiple receptacles, it does say the conductors must be sized for the rating of the branch circuit (and would include grounded or ungrounded conductors.
Per this information I don't see why you couldn't run 12 AWG on a 20 amp OCPD to some fixed loads and run a 14 AWG grounded conductor as long as the loads don't exceed the ampacity of the 14 AWG conductor. Little unconventional, but should meet code.
OK, this is your section as you mentioned,
Exception No. 2: The neutral conductor of a 3-wire branch
circuit supplying a household electric range, a wall-mounted
oven, or a counter-mounted cooking unit shall be permitted to
be smaller than the ungrounded conductors where the maximum
demand of a range of 83⁄4-kW or more rating has been
calculated according to Column C of Table 220.55, but such
conductor shall have an ampacity of not less than 70 percent of
the branch-circuit rating and shall not be smaller than 10 AWG.
My question pertains to relation between neutral and ground not neutral and line.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
No it doesn't apply to the neutral and ground on branch circuits. A #6 circuits may have a #6 neutral but the equipment grounding conductor is based on T250.122 which is usually a #10. The neutral however, cannot be smaller than the equipment grounding conductor. Suppose there was a short from a hot conductor to a neutral... If the neutral was smaller than the equipment grounding conductor then it could possibly have too much impedance to trip the breaker.
The code however only allows a reduction for the neutral in the examples mentioned above
The code however only allows a reduction for the neutral in the examples mentioned above
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If that would be the reason why, then why are we permitted to pull multiple circuits of different sizes in same raceway?
Feeder neutral clearly stated in 215.2 that it can't be smaller than the requried EGC. Nothing in 210 like that other than the few things mentioned for specific situations, it doesn't limit reduction of neutral size to those examples rather it puts limitation on how much you can reduce the neutral in those specific instances.
If (and I have done this several times before) you were to run a 60 -100 amp circuit to a motor controller and then on the the motor and that motor controller happened to have 120 volt coil and that less than 40 VA coil was the only load on the neutral conductor you can have 6 to 1/0 AWG ungrounded conductors and pull a 14 AWG neutral for that coil. Does it need to clear the OCPD if there is a line to neutral fault, nearly as bad as it needs to clear the OCPD in a line to ground fault? If it burns the neutral open the fault is over, Most the time that will likely happen to some crimped on terminal and not to the conductor itself.
Feeder neutral - why they want it to be at least the size of EGC - not sure. Fact it has greater chance of being an unbalanced current carrying situation maybe a contributing factor.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I understand that 215 states that the neutral cannot be smaller than the equipment grounding conductor and I realize that this is not written in 210. You are assuming that the short would happen in a raceway, which it can but not as likely, when it is possible to happen elsewhere.
The only exception I see if for ranges and dryers and those neutrals are sized to be the same as the equipment grounding conductor not smaller. I can only surmise that a smaller neutral would not be allowed even though it is not necessarily written somewhere.
I remember asking this question at one of the big meetings and I can't recall the reasoning but the answer was the neutral cannot be smaller than the equipment grounding conductor for branch circuits.
The only exception I see if for ranges and dryers and those neutrals are sized to be the same as the equipment grounding conductor not smaller. I can only surmise that a smaller neutral would not be allowed even though it is not necessarily written somewhere.
I remember asking this question at one of the big meetings and I can't recall the reasoning but the answer was the neutral cannot be smaller than the equipment grounding conductor for branch circuits.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Sounds like an answer based on assumptions to me. If it is that important to not be any smaller than the EGC why wasn't it as plainly written many years ago in 210 like it is in 215, or someplace else that would cover both situations?
Maybe we need to find when 215.2(A)(2) or a former section with same information was first introduced and read up on the justification for adding it to know more.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Okay if I have a 20 amp circuit that has a 15 amp load could you install that with a 14 awg neutral?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Also this
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I addressed that in post 6, some instances I believe you can, isn't all that common to see it but per how code is worded I think you can. 210.19(A)(2) is one situation where it specifically does prohibit it.
Do those sections apply to grounded conductors? Does a 10 AWG feeder neutral of a 60 amp feeder circuit comply with 240.4?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Is a neutral a conductor? I think it applies...
There is a rule for that for feeders (as discussed) based on the load of the neutral...
Got to go-- carry on...
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
right and the neutral isn't ordinarily directly protected by an overcurrent device, and in general can not be unless the device simultaneously opens ungrounded conductors as well.Is a neutral a conductor? I think it applies...
There is a rule for that for feeders (as discussed) based on the load of the neutral...
Got to go-- carry on...
The most protected neutral is that of a two wire circuit, what comes in the load must go out the other conductor there, any neutral carrying unbalance current can be subject to severe unbalancing that was never intended but that likelihood may be very limited in some situations, like say with my previously mentioned 120 volt motor starter contactor coil being the only load that gets connected to the neutral.
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