Lighting circuit between buildings with separate sub panels?

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whackit

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Los Angeles, CA
Hello,

I have a situation where there is a separate outbuilding next to a main residence.

The owner would like to have switches controlling the outdoor lights from both buildings. Each building has its own dedicated sub panel. So if we wired the lights from the main to the outbuilding the outbuilding would have a lighting circuit that would not be shut off by it's main breaker since it is powered by a main building circuit. Does that make sense? Not sure if this is Kosher or not.

Thanks for your help!
 
I think I may have found it:

225.30 Number of Supplies

(D) Different Characteristics.
Additional feeders or branch circuits supply-services shall be permitted for different voltages, frequencies, or phases or for different uses, such as control of outside lighting from multiple locations.

I'm assuming this provison would also allow connection of solar arrays between buildings:

(A) Special Conditions.
Additional outside supplies feeders or branch circuits shall comply with 230.2(A). be permitted to supply the following:

(5) Parallel power production systems

 
I've done this by using relays. In the house, I installed a 24VAC doorbell-style transformer and used standard 3-way switches for control. I used the same switches in the outbuilding. 24VAC relays switched the lighting (and several other loads) remotely, in the outbuilding. I connected the two buildings with multi-conductor direct burial sprinkler control wire.

http://www.sprinklerwarehouse.com/Multi-Strand-Irrigation-Wire-p/18-13.htm

Since all the switching was done at 24VAC, there were no "multiple supplies" issue between the two buildings. I even controlled an existing yard light, powered from the house's service, with a switch in the garage (that relay was in the house).

Worked like a charm, and the cost savings in wire more than made up for the enclosure and relays that were needed. The cable has spares for future expansion or if a conductor goes bad at some point.

The buildings had separate metered services, so that approach kept the inspector happy.


SceneryDriver
 
I'm sure I can do any of that but if permitted I would rather just run a wire between the two buildings. RF switches all go bad eventually and a relay based system is just a bit complex. It seems that the specific example is outlined in 225.30 (D).

(D) Different Characteristics.
Additional feeders or branch circuits supply-services shall be permitted for different voltages, frequencies, or phases or for different uses, such as control of outside lighting from multiple locations.
 
Just install a disconnect next to the disconnect for the building. You can use a 3 pole switch to disconnect the 3 way and I think you would have a compliant situation
 
run the circuit from the remote building instead of the main building, turn off the supply to remote building - lighting circuit is dead.

If you do it the other way around (circuit supplied by main building) then when you turn off the supply to remote building - you still have a second feed that is still live.

I guess if both buildings are on separate supply (as thread title indicates) it gets more complex. In that case if not using something wireless maybe use a class 2 circuit for control or a Tennessee three way - one switch with long pull string routed to multiple operating stations:cool:
 
whackit said:
Hello,

I have a situation where there is a separate outbuilding next to a main residence.

The owner would like to have switches controlling the outdoor lights from both buildings. Each building has its own dedicated sub panel. So if we wired the lights from the main to the outbuilding the outbuilding would have a lighting circuit that would not be shut off by it's main breaker since it is powered by a main building circuit. Does that make sense? Not sure if this is Kosher or not.

Thanks for your help!
Click to expand...

Since you are only controlling out door lighting,

you are allowed for example a three way switch one at the first building and one at the second building.

Since you have concern for one of the switch locations you can use signage indicating the supply for the lighting circuit is located at the other building.
 
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