# Switching one leg or both?



## Meadow (Jan 14, 2011)

When feeding lights with 208volts, do wall switches need to interrupt both legs or is only breaking one allowed? I have a box full of 277 volt singe pole switches:whistling2:


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## Black Dog (Oct 16, 2011)

meadow said:


> When feeding lights with 208volts, do wall switches need to interrupt both legs or is only breaking one allowed? I have a box full of 277 volt singe pole switches:whistling2:


410.104 Electric-Discharge Lamp Auxiliary Equipment.
(A) Enclosures. Auxiliary equipment for electric-discharge lamps shall be enclosed in noncombustible cases and treated as sources of heat.


(B) Switching. Where supplied by the ungrounded conductors of a circuit, the switching device of auxiliary equipment shall simultaneously disconnect all conductors.


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## Meadow (Jan 14, 2011)

Black Dog said:


> 410.104 Electric-Discharge Lamp Auxiliary Equipment.
> (A) Enclosures. Auxiliary equipment for electric-discharge lamps shall be enclosed in noncombustible cases and treated as sources of heat.
> 
> 
> (B) Switching. Where supplied by the ungrounded conductors of a circuit, the switching device of auxiliary equipment shall simultaneously disconnect all conductors.


Thanks!


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## 480sparky (Sep 20, 2007)

Black Dog said:


> ........(B) Switching. Where supplied by the ungrounded conductors of a circuit, the switching device of auxiliary equipment shall simultaneously disconnect all conductors.



Does this mean the _auxiliary equipment_, when supplied by only the grounded and grounding, doesn't need to disconnect anything?

Or does this mean if the _auxiliary equipment_, in addition to disconnecting the ungrounded conductor(s), must also disconnect the grounded and grounding as well?


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## Black Dog (Oct 16, 2011)

480sparky said:


> Does this mean the _auxiliary equipment_, when supplied by only the grounded and grounding, doesn't need to disconnect anything?
> 
> Or does this mean if the _auxiliary equipment_, in addition to disconnecting the ungrounded conductor(s), must also disconnect the grounded and grounding as well?


:laughing:

Good catch, typo:laughing:


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## Meadow (Jan 14, 2011)

From the looks of it this rule only applies to HID?


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## Big John (May 23, 2010)

meadow said:


> From the looks of it this rule only applies to HID?


 Also fluorescents.


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## Meadow (Jan 14, 2011)

Big John said:


> Also fluorescents.


Id imagine LEDs to then 

Guess Im going to need contactors for any 3 way switching too.


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## Big John (May 23, 2010)

LEDs aren't discharge lighting. It may seem like a silly loop-hole, but I'm not certain you'd be required to switch both legs by the letter of the law.


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## five.five-six (Apr 9, 2013)

I like the idea of having all conductors connected to a fixture being De-energized when the fixture is switched off regardless of code requirements.


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## 480sparky (Sep 20, 2007)

five.five-six said:


> I like the idea of having all conductors connected to a fixture being De-energized when the fixture is switched off regardless of code requirements.


That's the difference between a control and a disconnect. A control is designed to perform a function with the least amount of mechanization. If a 240v light has one hot switched off, the light goes out. That is a _control_. Turn off 2 legs of a 3-phase motor and it stops running. You are _controlling_ it.

A _disconnect_, on the other hand, is designed to turn off all power sources for the purpose of safely working on the item.


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## five.five-six (Apr 9, 2013)

480sparky said:


> That's the difference between a control and a disconnect. A control is designed to perform a function with the least amount of mechanization. If a 240v light has one hot switched off, the light goes out. That is a _control_. Turn off 2 legs of a 3-phase motor and it stops running. You are _controlling_ it.
> 
> A _disconnect_, on the other hand, is designed to turn off all power sources for the purpose of safely working on the item.


I understand that, no reason that control and disconnect functionality can not be contained in the same device. 

Believe it or not, sometimes some customers choose to preform their own service down the line, I just think it's safer for them.


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## 480sparky (Sep 20, 2007)

five.five-six said:


> I understand that, no reason that control and disconnect functionality can not be contained in the same device.
> 
> Believe it or not, sometimes some customers choose to preform their own service down the line, I just think it's safer for them.



If you disconnect all sources of power, you are also controlling it by doing so. So, all disconnects are controls, in this case.


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## Meadow (Jan 14, 2011)

So I take it as long as those switches are just to control the lights its allowed?


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## chicken steve (Mar 22, 2011)

So all controls are _not_ disconnects , but all disco's _are_ controls ???

hmmm....:001_huh:


~CS~


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## Meadow (Jan 14, 2011)

chicken steve said:


> So all controls are _not_ disconnects , but all disco's _are_ controls ???
> 
> hmmm....:001_huh:
> 
> ...



They way I view it is like this: If its required to kill power for service its a disconnect. If its just turning off the machine or light its not required to break all hots.

Reading the code my take is incandescent and LED lights can just break one hot, but the breaker which is the service disconnect breaks both.


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