Travelers between detached buildings

[chops101]

I am well into converting a 24 x 32 horse stable to a car shop (Garage Gallery).
The stable, and main house, were built exactly at the same time in 1997.
The stable is fed power by a 20A breaker off of one of the two main house sub panels. There is no disconnect, no feeder panel, nothing at the stable end just a small 4"x4" workbox on the outside (embedded in cement) of the barn with wire nuts. Along with this wimpy feed, there are a couple travelers that control an outside flood light on the barn; a 3-way switch is on the side of the barn, and the remote 3 way switch is deep into the main house family room (about 125' away from barn). I have to believe this was all proper code at the time, as it would have been impossible to slip this by any inspectors as the main house was under construction too.

Of course 20A won't begin to fulfill my shop needs and I have to address the power feed which I will do with a 90A circuit feeding a distribution box in the new shop (barn).

And I realize the existing 20A circuit should and will be abandoned...But, what about the travelers from the shop to the family room? It IS a cool feature, that I could use for lighting etc,

Q: Should the travelers be abandoned too? I hate to give it up as someone went to a lot of trouble to add this in at the time of both builds.

I did a search but did not find a scenario like this.
Thanks in advance.

 

[offroadsteve]

Short answer is no, you do not have to abandon the travelers and associated 3-way switch in the house. The caveat is that the power for the outside flood light must come from a circuit in the new barn electrical panel, and the switch in the house be connected only to wires originating in the garage.

The intent here is to avoid creating an alternate ground or neutral path from the garage to the house which parallels the feeder between the panel in the house and the yet-to-be-installed panel in the garage.

Full disclosure - I recently installed exactly this setup in my garage with a 4-way switch back to the house and the inspector didn't even bat an eye at it.

 

[kingchevy]

I have two separate 3 way circuits between my main house garage and new detached garage. One is for exterior lighting and it is fed from the house. The other is to power a relay that starts my compressor located in the main house garage, this one is fed by a detached garage lighting circuit. The neutrals from theses circuits are of course kept separate where they terminate in the opposing buildings, but are you saying that the ground wires should also be kept separate? These circuits are all in one conduit separate from the subpanel feeder.

 

[chops101]

Makes sense, I'll keep the travelers and make sure they are energized by the shop circuit.

Thanks much.

 

[Alchymist]

I have two separate 3 way circuits between my main house garage and new detached garage. One is for exterior lighting and it is fed from the house. The other is to power a relay that starts my compressor located in the main house garage, this one is fed by a detached garage lighting circuit. The neutrals from theses circuits are of course kept separate where they terminate in the opposing buildings, but are you saying that the ground wires should also be kept separate? These circuits are all in one conduit separate from the subpanel feeder.

What was meant by separate was that the wires from the outbuilding not connect to anything in the house except the switch box itself. There should be no connection to the ground within the house. The intent is to have one and only one ground path between the two buildings. In other words, for the ground at the house switch to reach actual ground - (the EGC bus in the main panel), it has to travel from the switch to the outbuilding subpanel and the back to the main panel on the 4 wire feed that connects the sub to the main panel - no shortcuts in the house. It also means there is only 1 path for current to reach the outbuilding from the main panel.

Clear as mud, right?