Spa

SAP

Senior Member
Location
Fresno Ca
Home owner ran 3/4 pvc,I was planing on running my two hots and neutral in #6 with a 8 ground,I want to make the pull easy has possible, 240 GFCI can I run my two Hots in 6awg and my neutral in 8 AWG thank you
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
IMO, if the wire is a feeder then you can down size the neutral but the branch circuit part cannot be down sized. This is one of those ridiculous differences between a feeder and a branch circuit.

215.2(A)(2) Grounded Conductor. The size of the feeder circuit
grounded conductor shall not be smaller than that required
by 250.122, except that 250.122(F) shall not apply where
grounded conductors are run in parallel.
Additional minimum sizes shall be as specified in
215.2(A)(2) and (A)(3) under the conditions stipulated.
 

kwired

Electron manager
Location
NE Nebraska
IMO, if the wire is a feeder then you can down size the neutral but the branch circuit part cannot be down sized. This is one of those ridiculous differences between a feeder and a branch circuit.
There is no similar section in art 210, but at same time there is nothing in 210 that would prohibit a reduced size grounded conductor either.

Some spa instructions require 6 AWG conductors for all four conductors :huh: even though NEC would otherwise permit 8 AWG and a 10 AWG EGC, I don't know why.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
There is no similar section in art 210, but at same time there is nothing in 210 that would prohibit a reduced size grounded conductor either.
That is debatable. Here is a section that can be used to argue what you stated and since there is no exception excluding the range grounded conductor (210.19(A)(3) then IMO it must be the same size.

Now how stupid is it that I can run a reduced neutral on the feeder side Panel to disconnect) but not on the branch circuit side (disconnect to tub). I brought this up at a meeting of the cmp members in Raleigh last year and the answer was the entire run should be looked at as a branch circuit--- yeah but that is not what the code states.


210.19(A) said:
(1) General. Branch-circuit conductors shall have an ampacity
not less than the maximum load to be served. Conductors
shall be sized to carry not less than the larger of
210.19(A)(1)(a) or (b).
(a) Where a branch circuit supplies continuous loads
or any combination of continuous and noncontinuous loads,
the minimum branch-circuit conductor size shall have an
allowable ampacity not less than the noncontinuous load
plus 125 percent of the continuous load.
(b) The minimum branch-circuit conductor size shall
have an allowable ampacity not less than the maximum
load to be served after the application of any adjustment or
correction factors.
Exception: If the assembly, including the overcurrent devices
protecting the branch circuit(s), is listed for operation
at 100 percent of its rating, the allowable ampacity of the
branch-circuit conductors shall be permitted to be not less
than the sum of the continuous load plus the noncontinuous
load.
Some spa instructions require 6 AWG conductors for all four conductors :huh: even though NEC would otherwise permit 8 AWG and a 10 AWG EGC, I don't know why.
This I agree with and have personally seen in the manuals. Thus I almost always use conduit for the run
 

kwired

Electron manager
Location
NE Nebraska
I did read 210.19 before posting before, all it says is "conductors shall have an ampacity not less than the maximum load to be served".

If you have a 50 or 100 amp branch circuit but the neutral load is only controls that amount to a few VA, then the load served by that conductor is only a few VA isn't it? This is the one example I run into often - a machine that only has a neutral load that is just a contactor coil or maybe a couple other control relays and that is it. Would you run a 100 amp neutral conductor to this machine even though the load is just a contactor coil?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
I did read 210.19 before posting before, all it says is "conductors shall have an ampacity not less than the maximum load to be served".

If you have a 50 or 100 amp branch circuit but the neutral load is only controls that amount to a few VA, then the load served by that conductor is only a few VA isn't it? This is the one example I run into often - a machine that only has a neutral load that is just a contactor coil or maybe a couple other control relays and that is it. Would you run a 100 amp neutral conductor to this machine even though the load is just a contactor coil?

I think that the minimum branch circuit size includes the neutral since it is part of the branch circuit. By your interpretation I could pull a #14 neutral with #4 conductors that are on an 80 amp overcurrent protective device. We know you can't do that because the neutral should never be less than the equipment grounding conductor. My point is where in your interpretation does that come into play
 

kwired

Electron manager
Location
NE Nebraska
I think that the minimum branch circuit size includes the neutral since it is part of the branch circuit. By your interpretation I could pull a #14 neutral with #4 conductors that are on an 80 amp overcurrent protective device. We know you can't do that because the neutral should never be less than the equipment grounding conductor. My point is where in your interpretation does that come into play
The neutral never being less then the equipment grounding conductor rule only comes up in 215.2(A)(2) which applies to feeders.

There is no requirement mentioned for branch circuits other then "conductors shall have an ampacity not less than the maximum load to be served".

The grounded conductor is not put there to handle ground faults like the EGC is, though it sort of makes sense in some instances that it should be no smaller then the EGC, but why don't they state something similar to 215.2(A)(2) somewhere in 210 if that is what is intended?

I still see no reason to run anything more then a 14 AWG for a conductor that is grounded and only carries a few VA.

What if the 100 amp ungrounded conductor faults in the raceway to the 14 AWG grounded conductor? My answer is a question: What if you ran a 100 amp branch circuit and a 15 amp branch circuit in same raceway (which is legal) and an ungrounded conductor of the 100 amp circuit faults to the grounded conductor of the 15 amp circuit?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
The neutral never being less then the equipment grounding conductor rule only comes up in 215.2(A)(2) which applies to feeders.
Yes I know that and mentioned that there is no rule like that under branch circuits hence my question about using A 14 AWG.

The grounded conductor is not put there to handle ground faults like the EGC is, though it sort of makes sense in some instances that it should be no smaller then the EGC, but why don't they state something similar to 215.2(A)(2) somewhere in 210 if that is what is intended?
I totally disagree. The grounded conductors primary purpose is not for ground fault but good design must account for it and it may have to carry a fault just as the other conductors may

I still see no reason to run anything more then a 14 AWG for a conductor that is grounded and only carries a few VA.
Well I do
 

kwired

Electron manager
Location
NE Nebraska
Yes I know that and mentioned that there is no rule like that under branch circuits hence my question about using A 14 AWG.

I totally disagree. The grounded conductors primary purpose is not for ground fault but good design must account for it and it may have to carry a fault just as the other conductors may

Well I do

So if you had multiple circuits in a raceway or even within same box, cabinet, or other enclosing apparatus, (this does happen in panelboard cabinets all the time) say varying from 100 amp to 15 amp you would run 100 amp conductors for the 15 amp circuits just in case they become faulted to the 100 amp circuits?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
So if you had multiple circuits in a raceway or even within same box, cabinet, or other enclosing apparatus, (this does happen in panelboard cabinets all the time) say varying from 100 amp to 15 amp you would run 100 amp conductors for the 15 amp circuits just in case they become faulted to the 100 amp circuits?
No but what is the likelihood of that. It is more likely to happy at the boxes, equipment etc. A short to ground would be dealt with by the equipment grounding conductor of the largest circuit but a neutral to hot fault in a conduit is not likely but I see your point. I still disagree with you so there--:p
 
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