six circuit transfer switch with no neutral

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Greg1707

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Alexandria, VA
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Business owner Electrical contractor
I installed a six circuit manual transfer switch. The switch came with a prewired flex whip with six pairs of conductors for the six switches as well as a ground and a neutral. The neutral ran from the main panel through the transfer switch to the generator power inlet.

When the transfer switches are in the normal position (poco feed) the neutral is not carrying any power. Theoretically, would this not have the potential to create an ectoplasmic overheating reaction of the current carrying conductors? I thought conductors had to be paired with a neutral to avoid over heating??

http://www.homedepot.com/catalog/pdfImages/33/33c57fd7-da79-4d14-8324-35a21cb4f83e.pdf
 
Greg1707 said:
I installed a six circuit manual transfer switch. The switch came with a prewired flex whip with six pairs of conductors for the six switches as well as a ground and a neutral. The neutral ran from the main panel through the transfer switch to the generator power inlet.

When the transfer switches are in the normal position (poco feed) the neutral is not carrying any power. Theoretically, would this not have the potential to create an ectoplasmic overheating reaction of the current carrying conductors? I thought conductors had to be paired with a neutral to avoid over heating??

http://www.homedepot.com/catalog/pdfImages/33/33c57fd7-da79-4d14-8324-35a21cb4f83e.pdf
Click to expand...

No idea, but I think you meant "exothermic", unless there are ghosts in the machine. eta: also, link doesnt work
 
Greg1707 said:
I installed a six circuit manual transfer switch. The switch came with a prewired flex whip with six pairs of conductors for the six switches as well as a ground and a neutral. The neutral ran from the main panel through the transfer switch to the generator power inlet.

When the transfer switches are in the normal position (poco feed) the neutral is not carrying any power. Theoretically, would this not have the potential to create an ectoplasmic overheating reaction of the current carrying conductors? I thought conductors had to be paired with a neutral to avoid over heating??

http://www.homedepot.com/catalog/pdfImages/33/33c57fd7-da79-4d14-8324-35a21cb4f83e.pdf
Click to expand...

Electrically would this be any different than six 2-wire switch loops?
 
infinity said:
Electrically would this be any different than six 2-wire switch loops?
Click to expand...
Exactly, the neutral serves no purpose at all unless it supplies some control circuitry of the transfer equipment itself.

External effects of magnetic fields of each conductor is cancelled by the "return" conductor of same circuit.
 
kwired said:
Exactly, the neutral serves no purpose at all unless it supplies some control circuitry of the transfer equipment itself.

External effects of magnetic fields of each conductor is cancelled by the "return" conductor of same circuit.
Click to expand...

But is it code compliant? 300.3(B) is pretty explicit in stating that the neutral needs to be run in the same raceway at the phase conductors unless you can say that this falls under switch loops.
 
infinity said:
But is it code compliant? 300.3(B) is pretty explicit in stating that the neutral needs to be run in the same raceway at the phase conductors unless you can say that this falls under switch loops.
Click to expand...
My question is why wouldn't these be switch loops the way they are typically arranged? And outside of control purposes of the transfer switch what purpose does the neutral serve?
 
kwired said:
My question is why wouldn't these be switch loops the way they are typically arranged? And outside of control purposes of the transfer switch what purpose does the neutral serve?
Click to expand...

No purpose so IMO it's useless to bring the neutral along for the ride, but what specific code wording would allow this arrangement?
 
infinity said:
No purpose so IMO it's useless to bring the neutral along for the ride, but what specific code wording would allow this arrangement?
Click to expand...
300.3(B) that you mentioned.

"All conductors of the same circuit and, where used, the grounded conductor". I don't think the grounded conductor is used in this case, even though it is still there.
 
kwired said:
300.3(B) that you mentioned.

"All conductors of the same circuit and, where used, the grounded conductor". I don't think the grounded conductor is used in this case, even though it is still there.
Click to expand...

If the circuits are 120 volts the grounded conductor is used just not in the transfer equipment but it is still part of the circuit.
 
infinity said:
If the circuits are 120 volts the grounded conductor is used just not in the transfer equipment but it is still part of the circuit.
Click to expand...
And as you mentioned earlier the switch loop situation - which is IMO exactly what this is.

AFAIK the reason for the rule is to cancel magnetic effects, what current goes one way in a raceway or cable must come back the other way on one or more other conductors. A neutral or any other conductor that is not being used has no effect one way or the other. They do want the EGC included so that it helps lower impedance during ground faults though, but you still can get ground faults that pass current over other routes.

Could they have worded it differently to make that more clear - possibly.
 
infinity said:
If the circuits are 120 volts the grounded conductor is used just not in the transfer equipment but it is still part of the circuit.
Click to expand...
Generally speaking, the neutral is used in the transfer equipment when on generator. At that point the circuits are fused via the button fuses on the transfer panel. In a normal, non-power fail condition I guess you could consider a Gen-Tran panel a switch panel. However, now the question is, if all circuit wires have to originate in the panel they are fed from will this still be the case in a power fail mode using a Gen-Tran panel ? The circuits are being fed from a generator, through the Gen-Tran panel and to the respective circuits. In power fail mode the circuit wires are no longer protected via the breaker panel. Basically that # 10 white wire in the Gen-Tran panel is an extension of the neutral bar in the breaker panel.

I don't mean to pirate this thread away from the OP but another question arises with respect to using Gen-Tran panels. If you use a 10 circuit transfer panel does the six-switch rule apply ? Is the attachment cord and plug or the breaker on the generator considered an adequate protection and disconnect means for that panel ?
 
iwire said:
Does the NEC apply here? IMO no.
Click to expand...

I agree that it shouldn't but the wording doesn't seem to agree because the conductors (H&N for 120 volts) are used and there is a raceway involved.


300.3 Conductors.
(B) Conductors of the Same Circuit. All conductors of
the same circuit and, where used, the grounded conductor
and all equipment grounding conductors and bonding con-
ductors shall be contained within the same raceway, auxil-
iary gutter, cable tray, cablebus assembly, trench, cable, or
cord, unless otherwise permitted in accordance with
300.3(B)(1) through (B)(4).
Click to expand...

300.4(I) Conductors of the Same Circuit. All conductors of
the same circuit and, where used, the grounded conductor
and all equipment grounding conductors shall be installed
in the same raceway or cable or shall be installed in close
proximity in the same trench.
Click to expand...
 
infinity said:
I agree that it shouldn't but the wording doesn't seem to agree because the conductors (H&N for 120 volts) are used and there is a raceway involved.
Click to expand...

I am suggesting the NEC does not apply to this at all.

From the OP

I installed a six circuit manual transfer switch. The switch came with a prewired flex whip with six pairs of conductors for the six switches as well as a ground and a neutral.
Click to expand...

That sounds like internal wiring of listed and labeled equipment to me.
 
goldstar said:
Generally speaking, the neutral is used in the transfer equipment when on generator. At that point the circuits are fused via the button fuses on the transfer panel. In a normal, non-power fail condition I guess you could consider a Gen-Tran panel a switch panel. However, now the question is, if all circuit wires have to originate in the panel they are fed from will this still be the case in a power fail mode using a Gen-Tran panel ? The circuits are being fed from a generator, through the Gen-Tran panel and to the respective circuits. In power fail mode the circuit wires are no longer protected via the breaker panel. Basically that # 10 white wire in the Gen-Tran panel is an extension of the neutral bar in the breaker panel.

I don't mean to pirate this thread away from the OP but another question arises with respect to using Gen-Tran panels. If you use a 10 circuit transfer panel does the six-switch rule apply ? Is the attachment cord and plug or the breaker on the generator considered an adequate protection and disconnect means for that panel ?
Click to expand...
I have never wired one of these in, but as far as the need of a neutral in the generator panel depends on arrangement of certain items.

Does generator input leads enter via same flexible conduit?
-if so neutral isn't really needed unless there is 120 volt controls for transfer equipment. Cancellation of magnetic fields is still achieved because the supply conductor(s) and return conductor(s) are all in the same raceway.

-if not then the neutral is needed to connect the generator neutral output to the normal power panel neutral - where the neutral conductors of the transferred branch circuits are landed. Still leaving you a balance of canceling magnetic fields in the flex conduit.

Six disconnect rule wouldn't apply here, this is just a panel supplied by a feeder and not the main service or feeder to the building.When running in standby mode there is a single disconnect ahead of this panel - often at the generator.
 
When the transfer switches are in the normal position current comes from breaker to transfer switch and returns to connect to branch wiring. No net current in raceway, so no magnetic effects.
If the transfer switch is in the generator position the current is unbalanced *and* you could argue that the hot wire of the branch and the associated neutral are not originating in the same panel.

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