3 phase disconnect but using only single phase.

[Mustangx3]

Is there any issue or "code" problem with using a 3 phase disconnect for a single phase circuit and just omitting the other legs?

 

[infinity]

I don't see any unless you can find something to do with the listing of the disconnect. Some even show single phase applications on their label.

 

[raider1]

I agree with Rob, I am not aware of anything prohibiting using just 1 or 2 poles of a 3 phase disconnect.

Chris

 

[Mustangx3]

Thanks, that's what I had understood...

 

[LarryFine]

Some even show single phase applications on their label.

And, usually specify to use the outer poles for 2 lines.

 

[benaround]

And, usually specify to use the outer poles for 2 lines.

So they don't show how to connect if only using one pole ?

 

[mxslick]

So they don't show how to connect if only using one pole ?

Just use the center pole. :grin:

Just as a guess, I'm thinking they specify using the two outer poles only to maintain separation on the legs.

 

[jeremysterling]

I believe for DC the B pole and C pole are wired in series.

 

[LarryFine]

And, usually specify to use the outer poles for 2 lines.

So they don't show how to connect if only using one pole ?

Just use the center pole. :grin:

Just as a guess, I'm thinking they specify using the two outer poles only to maintain separation on the legs.

Nah, it's all about the asthetics of symmetry.

 

[LarryFine]

I believe for DC the B pole and C pole are wired in series.

That helps extinguish contact arcing faster.

 

[kbsparky]

We just installed a 400 Amp fusible safety switch on a revamped service.

Service is single phase, 120/240 Volts.

Supply house had given us a quote for a single phase safety switch, but did not have one available for us within a timely manner, so they "gave" us a 3-pole unit instead.

So now, we have a "spare" pole in case one of the others burns out at some time

 

[Cavie]

Is there any issue or "code" problem with using a 3 phase disconnect for a single phase circuit and just omitting the other legs?

We are forced to do it all the time in street lighting. 480 volts 1 phase, one leg to ground. Have to use 600 volt, 3 phase breakers and contactors all the time.

 

[kwired]

many manufacturers do not make certain configurations of switches in certain sizes and in their catalogs they state to use other configurations for an application.

Example Sq D catalog if I am looking for a 2 pole 30, 60,100 or 200 amp 600 volt fused switch they have no catalog numbers for any of these instead it says to use 3 wire devices for 2 wire applications.