# 240volt Lighting



## Thunder (May 21, 2008)

Can you 3 way or 4 way switch with 240 v lighting?


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## erics37 (May 7, 2009)

Yes.


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## MDShunk (Jan 7, 2007)

Sure, but you have to do it through a contactor. I don't believe anyone makes 3-way or 4-way 2-pole switches.


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## erics37 (May 7, 2009)

Fine I guess I'll flesh out my first answer :laughing:

Treat one leg as a "neutral" (even though it's not) and switch the other leg like you would a normal 120V circuit. Make sure the switches are rated for the voltage.

Alternatively, use a normal 120V 3-way switch circuit to switch a contactor, and just run the 240V circuit through it.


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## erics37 (May 7, 2009)

MDShunk said:


> Sure, but you have to do it through a contactor.


Why?


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## MDShunk (Jan 7, 2007)

erics37 said:


> Why?


Because of the requirement for switches on this type of lighting to break both legs. :thumbsup:


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## Thunder (May 21, 2008)

erics37 said:


> Fine I guess I'll flesh out my first answer :laughing:
> 
> Treat one leg as a "neutral" (even though it's not) and switch the other leg like you would a normal 120V circuit. Make sure the switches are rated for the voltage.
> 
> Alternatively, use a normal 120V 3-way switch circuit to switch a contactor, and just run the 240V circuit through it.


Thank you- so there will always be 120 at the light but it wont turn on the fixture without the other 120


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## erics37 (May 7, 2009)

MDShunk said:


> Because of the requirement for switches on this type of lighting to break both legs. :thumbsup:


Oh you're bringing code into this.


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## erics37 (May 7, 2009)

CarlCantelon said:


> Thank you- so there will always be 120 at the light but it wont turn on the fixture without the other 120


Shunk's right, it's against code to leave one of the hot legs on the ballast and switch the other.

But it'd work :whistling2:


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## Thunder (May 21, 2008)

It was just a question I had in theory, I was wondering if 120v would turn on a 240v fixture. I thought maybe the 120 would just dim the light.


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## erics37 (May 7, 2009)

CarlCantelon said:


> It was just a question I had in theory, I was wondering if 120v would turn on a 240v fixture. I thought maybe the 120 would just dim the light.


You need a complete circuit for current to flow, if a switch is open, there is an open circuit and therefore no current. Even if you can measure 120 volts from the unswitched hot leg at the ballast.


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## MDShunk (Jan 7, 2007)

_*410.141 Control.
(A) Disconnection.* Luminaires or lamp installation shall be
controlled either singly or in groups by an externally operable
switch or circuit breaker that opens all ungrounded primary
conductors._


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## frenchelectrican (Mar 15, 2007)

That one reason why with 240 volts luminaire circuits ( North Americiane side ) if you going have more than one switch to control this circuit I rather run thru the contractor it much safer this way as Americian Marc mention Art 410.141 that is clear cut answer.

Merci,
Marc 

Note: Our European system basically the same result when we run on 415 volt circuits. the 240 volts on our side is the same as your 120 or 277 volt circuits.


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## oldtimer (Jun 10, 2010)

Many 240 volt baseboard heaters are controlled by a single pole thermostat.

Why is it different for 240 volt lighting?

If you switch one leg, you are still interrupting the completed circuit.

I do not know if this is acceptable for lighting, but if it isn't, then why?



Anyone???


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## backstay (Feb 3, 2011)

oldtimer said:


> Many 240 volt baseboard heaters are controlled by a single pole thermostat.
> 
> Why is it different for 240 volt lighting?
> 
> ...


Maybe it would be a shock hazard. Think switch off and changing a broken bulb.


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## MasterE (Dec 31, 2011)

MDShunk said:


> _*410.141 Control.
> (A) Disconnection.* Luminaires or lamp installation shall be
> controlled either singly or in groups by an externally operable
> switch or circuit breaker that opens all ungrounded primary
> conductors._


I believe this is referring to Lighting Systems over 1000V in section XIV
I did not see any thing for less than 1000V


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## erics37 (May 7, 2009)

MasterE said:


> I believe this is referring to Lighting Systems over 1000V in section XIV
> I did not see any thing for less than 1000V


Good point. Shunk, how do you respond?

Maybe I was accidentally right to begin with :laughing:


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## MasterE (Dec 31, 2011)

Here in Wisconsin I did check with one of the State inspectors on this. I installed 
240 V lighting and switched it with a three way breaking one leg of the 240v.
The lighting fixtures have there own disconnect by unplugging the ballast internally, and the circuit is fed from a two pole breaker witch can be locked out. This eliminates the use of contactors. The inspector said this was fine and no code violation.


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## Thunder (May 21, 2008)

Thank you for answering my question so fully I never expected to learn as much as I did thank you again


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## don_resqcapt19 (Jul 18, 2010)

MasterE said:


> I believe this is referring to Lighting Systems over 1000V in section XIV
> I did not see any thing for less than 1000V


See 410.104(B)


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## MasterE (Dec 31, 2011)

What would be the auxiliary equipment. Em Ballast?


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## jza (Oct 31, 2009)

CarlCantelon said:


> It was just a question I had in theory, I was wondering if 120v would turn on a 240v fixture. I thought maybe the 120 would just dim the light.


lol, you don't know very much about electrical theory, do you?


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## don_resqcapt19 (Jul 18, 2010)

MasterE said:


> What would be the auxiliary equipment. Em Ballast?


The ballast itself is the "auxiliary equipment".


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## MasterE (Dec 31, 2011)

don_resqcapt19 said:


> The ballast itself is the "auxiliary equipment".


I don't think so, I believe the auxiliary (extra) equipment they are referring to is 
like a quarts lamp in HID high bays so if the lights momentarily drop out the quarts come on until the hid re strikes.


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## electrictim510 (Sep 9, 2008)

I'll check for the article but I'm sure it is not code to switch only one of two legs. Like backstay said it would be a shock hazard.


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## electrictim510 (Sep 9, 2008)

410.93, 410.104(b)..


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## don_resqcapt19 (Jul 18, 2010)

MasterE said:


> I don't think so, I believe the auxiliary (extra) equipment they are referring to is
> like a quarts lamp in HID high bays so if the lights momentarily drop out the quarts come on until the hid re strikes.



All of the electrical parts, other than the lamp itself, are "auxiliary equipment" for all "discharge" type of fixtures.  



> High intensity discharge (HID) lamps require auxiliary equipment (ballasts, capacitors, ignitors or power supplies) to provide the correct electrical values for starting and operating.



The above is from
http://www.venturelighting.com/techcenter/ProperUse.html


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## Electric_Light (Apr 6, 2010)

CarlCantelon said:


> It was just a question I had in theory, I was wondering if 120v would turn on a 240v fixture. I thought maybe the 120 would just dim the light.


It depends on the fixture. 

If you hookup a commercial application fluorescent fixture to a center grounded source and one of the leg shorts to the ground, they will light up as if nothing is wrong, then overload something. This would be a problem if the breaker isn't the weakest link.

In an effort to prevent installation errors and inventory management issues, more often than not, commercial use fixtures have 120-277v ballast, which operate at anything in between.


So, if you wire them up for 240v and size wiring according to 240v but the other leg shorts to ground, the ballast will operate drawing twice the current and smoke one of the wires. 

Say you run lighting off of 240v in 240/120 Delta building. A 4 lamp T8 draws about 0.5A at 240v. You have 26 of them and you size wires with 13A of continuous current in mind. If the return path wires comes loose at Jbox and siwtch is turned on, the GFCI will pop... or the lights will draw 26A and keep on working.


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## 360max (Jun 10, 2011)

410.130(g)(2)


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