manual transfer switch

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Cleveland Apprentice

Senior Member
Location
Cleveland, Oh
Hello,

I have purchased a Protran manual transfer switch (10 individual switches). For those who are not familiar with it, it mounts next to the breaker box and has approx 1' long piece of 1" piece of FMT that connects to the breaker box. The FMT is not over 30" (cannot remember the rule for distance, correct me if I'm wrong) so no derating is necessary of the 20 ccc it contains.

The dilemma I have and not sure if this is against the NEC, is the HO has a 100 amp sub-panel off the 200 amp main panel where the transfer switch is mounted. There are a couple of circuits in the sub-panel he would like switched to generator power in addition to the majority of the circuits in the main panel. I am not sure how to do this considering that the neutral cannot be switched because this transfer switch does not switch neutrals. The HO wants to keep the circuits in the sub-panel where they are. I am wondering if I could run a couple of 12/3 from the sub-panel to the transfer switch, using the black wire as normal power from the sub-panel to transfer switch and the red as the load wire. The problem is the neutral would not run within the 12/3 since it cannot be switched. I would have to utilize the neutral in the feeder while under generator power. Does anyone see an issue with this? Thanks.
 
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augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I guess it would technically be a violation of 300.3(B), but I don't see it being much different than a two wire switch leg.
 

Cleveland Apprentice

Senior Member
Location
Cleveland, Oh

Smart $

Esteemed Member
Location
Ohio
The generator is portable and rated 5500 watts, 6500 surge watts. The transfer switch is rated 7500 watts max. The transfer switches is not set up to switch the neutrals
I'm not a proponent, but as posited in that other thread, not switching the neutral(s) would violate a UL portable generator listing, thus violate NEC 110.3(B).
 
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