Back porch light and detatched garage coach lights

[dec]

Ok guys...I heard this one today and do not agree with the answer: Two 3-ways control a house back porch light and two coach lights on a detached garage. The garage has a small sub-panel fed from the house. I was told only three ungrounded conductors were needed between the garage and house because the existing neutral for the back porch light is connected to the house service panel while the neutral for the garage coach lights are connected to the garage sub-panel. I say this is not correct because branch circuit neutrals have to be terminated at the origin of the branch circuit. If the branch circuit feeds from the garage sub-panel...then the neutral must also feed from the sub-panel. If the branch circuit feeds from the main house panel...likewise the neutral must also feed from the house panel since this is the origin of the branch circuit. Comments please !

 

[texie]

Ok guys...I heard this one today and do not agree with the answer: Two 3-ways control a house back porch light and two coach lights on a detached garage. The garage has a small sub-panel fed from the house. I was told only three ungrounded conductors were needed between the garage and house because the existing neutral for the back porch light is connected to the house service panel while the neutral for the garage coach lights are connected to the garage sub-panel. I say this is not correct because branch circuit neutrals have to be terminated at the origin of the branch circuit. If the branch circuit feeds from the garage sub-panel...then the neutral must also feed from the sub-panel. If the branch circuit feeds from the main house panel...likewise the neutral must also feed from the house panel since this is the origin of the branch circuit. Comments please !

I agree.

 

[GoldDigger]

I would ask where each of the three way circuits gets its ungrounded wire.
Even though it is a three way, the power will come from a circuit at only one end. Whichever end that is, for each circuit, is also where the grounded wire must originate.
You are allowed to have a light mounted on the house which is controlled from both house and garage, as long as the circuit originates from the house.
It gets trickier when one circuit controls lights on both buildings.
IMHO that is also allowed by code if the wiring on the non-origin building does not enter the building or serve loads inside the building.
All if this does make it interesting to successfully light a path from one building to the other which can be controlled from both ends.
At my current residence there is a five luminaire circuit originating at the garage with an inside switch and where one fixture is mounted on the exterior wall at the house end the other 3 way switch is on the outside wall in a weatherproof box. The travellers go in the same conduit with the power and neutral for the fixtures.
I think this is 100% allowed by NEC but I am not sure how far variations on the approach would go.
For example could the switches be inside the building at both ends? Would that vary with code cycle?


Tapatalk!

 

[ActionDave]

..... Comments please !

You are correct.