# 480 Volt twistlock Photocell,does it ?



## HARRY304E (Sep 15, 2010)

Here is a good question.

Does a 480 volt twist lock photocell switch two poles?

I just looked at the specs to many different brands and none of them say whether or not they do..


----------



## BBQ (Nov 16, 2010)

HARRY304E said:


> Here is a good question.
> 
> Does a 480 volt twist lock photocell switch two poles?
> 
> I just looked at the specs to many different brands and none of them say whether or not they do..


Wouldn't they need four prongs for that?


----------



## HARRY304E (Sep 15, 2010)

BBQ said:


> Wouldn't they need four prongs for that?


No I do not think so because the fixture would be single phase 2 hots and a neutral.

Of course I had a point in mind , I just can't think of what it was..:laughing:

Okay NEC 2011.

If a 480 volt photocell only breaks one hot,,Then that should be a violation of 410.104 

*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.


----------



## Bbsound (Dec 16, 2011)

I think a plug in fixture mounted photocell is a part of the fixture. Not auxilary equipment.


----------



## BBQ (Nov 16, 2010)

The ballast of an HID fixture is 'auxiliary equipment' to the lamp.

Read the section he posted again.


----------



## BBQ (Nov 16, 2010)

HARRY304E said:


> No I do not think so because the fixture would be single phase 2 hots and a neutral.


Harry, you can't switch both hots with less than four connections, think of any double pole switch.




> If a 480 volt photocell only breaks one hot,,Then that should be a violation of 410.104


In my opinion if an electrician was the one installing the photo cell like that it would be a violation.

If the factory does it .... not so much.


----------



## sparky970 (Mar 19, 2008)

Would it be any different for 277, 240, or 208?


----------



## Celtic (Nov 19, 2007)

HARRY304E said:


> ....the fixture would be single phase 2 hots and a neutral.



480v ballast requires a neutral?


----------



## HARRY304E (Sep 15, 2010)

Celtic said:


> 480v ballast requires a neutral?


No it should not..:laughing:


----------



## HARRY304E (Sep 15, 2010)

BBQ said:


> Harry, you can't switch both hots with less than four connections, think of any double pole switch.
> .


Good point.

I did not see any 2 pole 480 volt photocells.


----------



## Deep Cover (Dec 8, 2012)

Take a look at a standard 208V photocell. There are only three wires...black, red, and white. A similar question was posed a while back.

http://www.electriciantalk.com/f2/208v-photocell-45681/

It really doesn't answer your question Harry, but it does seem that every cell I've installed only switched one leg.


----------



## HARRY304E (Sep 15, 2010)

Deep Cover said:


> Take a look at a standard 208V photocell. There are only three wires...black, red, and white. A similar question was posed a while back.
> 
> http://www.electriciantalk.com/f2/208v-photocell-45681/
> 
> It really doesn't answer your question Harry, but it does seem that every cell I've installed only switched one leg.


Yup I saw that before , that does not meet the requirement of 410.104(B).


----------



## JRaef (Mar 23, 2009)

Even if the fixture is 480V, the photocell is not. If you have two hots and a neutral going to the ballast, the photocell will be 277V, getting it's power from one line and neutral. Therefore the twist lock only needs to break the one hot line. If you buy a "high voltage" 600V version for Canada it's still operated at 347V, so still only one hot needs to be broken.


----------



## BBQ (Nov 16, 2010)

JRaef said:


> If you have two hots and a neutral going to the ballast,



You have something very strange.


----------



## erics37 (May 7, 2009)

I think the only thing you could legally install a single-pole 480 volt photocell for would be to switch a 480 volt contactor which would run all the lights.

Given the relative expense of 480 volt crap it might be more worthwhile to run a 277 circuit dedicated to lighting controls. Circumstances dictating, of course.

Or just violate the code :jester:


----------



## wjcarty10 (Mar 9, 2013)

a 480 volt twist lock photocell only switches one leg of the circuit.. the other phase of the circuit is wired to the common on the ballast and photo cell, therefore does not need to be switched.. normally twist-lock photocells are part of the fixture, as long as the fixture is UL listed you shouldnt be in violation of anything.


----------



## erics37 (May 7, 2009)

wjcarty10 said:


> a 480 volt twist lock photocell only switches one leg of the circuit.. the other phase of the circuit is wired to the common on the ballast and photo cell, therefore does not need to be switched.. normally twist-lock photocells are part of the fixture, as long as the fixture is UL listed you shouldnt be in violation of anything.


If the whole thing is built as one big happy listed assembly including the photocell then you're right.

If you add the photocell yourself to switch the circuit, you need to switch all ungrounded conductors. Yeah it would still work only switching one leg - and I don't have any issue with doing it that way - but it's a code violation.


----------



## wjcarty10 (Mar 9, 2013)

yeah you are correct.. but like u said if we are adding a 480 volt photocell to the ckt.. i have never come across a double pole photo cell.. intermatic needs to come up with something for us


----------



## erics37 (May 7, 2009)

wjcarty10 said:


> yeah you are correct.. but like u said if we are adding a 480 volt photocell to the ckt.. i have never come across a double pole photo cell.. intermatic needs to come up with something for us


Yep that would be pretty handy :thumbup:


----------

