Double pole - Single throw Switches

[cwilliamson]

If you have a single gang box in an existing bathroom wall is it okay to bring the 277v light wires and the 120v fan wires to a double pole-single throw switch or should I change the box and use dividers?

 

[dnbob]

Re: Double pole - Single throw Switches

I think the d.p.s.t. switch would be fine as long as there is less than 300 vac between your terminals. Also as long as the switch is rated for the 277 v.

 

[stamcon]

Re: Double pole - Single throw Switches

Two circuits suppling a single yoke device requires a 2 pole common trip breaker.

 

[websparky]

Re: Double pole - Single throw Switches

Basically, it is not a safe idea. Most likely the inspector will not allow it. Unless you install the dividers.

In the past I have changed the ballasts to 120V or supplied a separate box and switch.

2002 NEC
404.8(B) Voltage Between Adjacent Devices. A snap switch shall not be grouped or ganged in enclosures with other snap switches, receptacles, or similar devices, unless they are arranged so that the voltage between adjacent devices does not exceed 300 volts, or unless they are installed in enclosures equipped with permanently installed barriers between adjacent devices.
Barriers are required between switches that are ganged in a box and used to control 277-volt lighting on 480Y/277-V systems where two or more phase conductors enter the box. Permanent barriers would be required between devices fed from two different phases of this system because the voltage between the phase conductors would be 480 volts, nominal, and would exceed the 300-volt limit. Barriers are required even if one device space is left empty because the two remaining devices fed from different phase conductors would still be adjacent to each other. This requirement now applies to switches ganged together with any wiring device where the voltage between adjacent conductors exceeds 300 volts.

 

[drg]

Re: Double pole - Single throw Switches

Originally posted by stamcon:
Two circuits suppling a single yoke device requires a 2 pole common trip breaker.

That sounds like a requirement on a multiwire branch circuit that I agree with, but the part that gets me is the 120v for the fan ......and then the 277v for the light.

I am looking at this as power coming from 2 different panels and this would not be a called a multiwired branch circuit.( I don't what I would call this).

This is just my view so comments welcome.


John

 

[charlie]

Re: Double pole - Single throw Switches

This question has been floating around for a long time. The official UL answer is that the switches have not been evaluated for that application and that type installation should be turned down. I suspect the answer can be proven in the UL White Book that I will not have access to until tomorrow.

 

[stamcon]

Re: Double pole - Single throw Switches

:roll: Oops, as to the common trip disconnect(210-4), that's only for "Dwelling Units".

steve

 

[pierre]

Re: Double pole - Single throw Switches

This is one of those areas of the code that has not been specifically addressed. As Charlie has said, the device has not been listed for the purpose. I would also reference 408.8(B) Voltages Between Adjacent Devices. There are some installations that are potentially too dangerous (switch changed by maintenance person in this case).

Pierre

 

[charlie]

Re: Double pole - Single throw Switches

In the UL White Book and category (WJQR), the following is found:

Multi-pole, general use snap switches have not been investigated for more than single circuit operation unless marked "2-circuit" or "3-circuit."

Other information seems to bolster my statement as well but it is foggy.