switching 240 volt LED with 240 volt photo cell

shade23

Member
I have a situation where I need to switch (2) LED outdoor flood lights using a Intermatic K4223K photo cell. The lights were installed at a military installation for a road sign. The lights are several hundred feet away from the power source and they are fed from the last (closest light pole) then to the sign.
Normally I would install a contactor with an eye but this will prove to be very difficult.
The fixtures are on bell boxs mounted to concrete.
Between the 2 fixtures is an in-ground junction box where everything terminates.
My question is since I can not locate a double pole photo cell can I switch the LED's by using the photo cell to switch one side of each fixture.
Even if it is legal I do not like swiching only one leg of 240 volts. I know it has been switched but someone else may not and that would be a major problem. Everything will be labeled but can I switch one leg and be legal?

Thank You
 

fmtjfw

Senior Member
I can find no requirement for double pole switching for the LEDs

I can find no requirement for double pole switching for the LEDs

Can't switch just one leg. 404.something is the code reference.
I'm not sure a photocell is a switch. These sections in 404 and 410 do not seem to apply:

404.2 (A) Three-Way and Four-Way Switches.
Three-way and four-way switches shall be wired so that all switching is done only in the ungrounded circuit conductor.
....
>>> not apply -- equivalent of an S1 switch

(B) Grounded Conductors.
Switches or circuit breakers shall not disconnect the grounded conductor of a circuit.
>>> doesn't

Exception: A switch or circuit breaker shall be permitted to disconnect a grounded circuit conductor where all circuit conductors are disconnected simultaneously, or where the device is arranged so that the grounded conductor cannot be disconnected until all the ungrounded conductors of the circuit have been disconnected.
>>> since grounded not opened, not all ungrounded need to be opened

404.15 Marking.
....
(B) Off Indication.
Where in the off position, a switching device with a marked OFF position shall completely disconnect all ungrounded conductors to the load it controls.
>>> there is no "off" position.

410.93 Double-Pole Switched Lampholders.
Where supplied by the ungrounded conductors of a circuit, the switching device of lampholders of the switched type shall simultaneously
disconnect both conductors of the circuit.
>>>There is no lampholder

410.104 Electric-Discharge Lamp Auxiliary Equipment.
....
(B) Switching.
Where supplied by the ungrounded conductors of a circuit, the switching device of auxiliary equipment shall simultaneously disconnect all conductors.
>>>Not electric-discharge equipment

XIII. Special Provisions for Electric-Discharge Lighting Systems of More Than 1000 Volts
....
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.
>>>Not over 1000V

A photocell is an automatic control. Consider a line-voltage thermostat -- without a marked off position. It need not disconnect all the ungrounded conductors. I suggest that a photocell-operated relay is no different and need not open all ungrounded conductors.
 
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ActionDave

Moderator
Staff member
Art. 410 is the one I was thinking of, and you are correct. LED's are a different animal that anything mentioned in the section I was thinking of.

Dang ole new fangled LED's are messing with my memory.
 

mirawho

Senior Member
The issue here, I think, is the location of the photocell. If this was mounted to the fixture, it would be considered part of the fixture and not auxiliary. All installations I have done or have seen have either had the photocell connected directly to the fixture or it controlled a contactor for the lighting circuits. Fmtjfw pointed out all of the code concerning disconnecting and switching of the circuits and here 410.104, which covers auxiliary equipment states the switching device of auxiliary equipment shall simultaneously disconnect all conductors. I know the code was written for electric discharge lamps, but I also think it applies in this case. You would either have to install the PC's on the fixtures or install a small contactor, which, from what you stated earlier, would be difficult.
 

fmtjfw

Senior Member
The issue here, I think, is the location of the photocell. If this was mounted to the fixture, it would be considered part of the fixture and not auxiliary. All installations I have done or have seen have either had the photocell connected directly to the fixture or it controlled a contactor for the lighting circuits. Fmtjfw pointed out all of the code concerning disconnecting and switching of the circuits and here 410.104, which covers auxiliary equipment states the switching device of auxiliary equipment shall simultaneously disconnect all conductors. I know the code was written for electric discharge lamps, but I also think it applies in this case. You would either have to install the PC's on the fixtures or install a small contactor, which, from what you stated earlier, would be difficult.
No the location makes no difference as far as I can see. The photocell is not a switch or a disconnect it is a control. Once again, controls, like line-voltage thermostat (without a "OFF" position) is not required to open all ungrounded conductors. See:

424.20 Thermostatically Controlled Switching Devices.

(A) Serving as Both Controllers and Disconnecting Means. Thermostatically controlled switching devices and combination thermostats and manually controlled switches shall be permitted to serve as both controllers and disconnecting means, provided they meet all of the following
conditions:

(1) Provided with a marked ?off? position

(2) Directly open all ungrounded conductors when manually placed in the ?off? position

(3) Designed so that the circuit cannot be energized automatically after the device has been manually placed in the ?off? position

(4) Located as specified in 424.19

(B) Thermostats That Do Not Directly Interrupt All Ungrounded Conductors. Thermostats that do not directly interrupt all ungrounded conductors and thermostats that operate remote-control circuits shall not be required to meet the requirements of 424.20(A). These devices shall not be permitted as the disconnecting means.

The requirement for opening all ungrounded conductors in the lighting article is generally to prevent contact with high voltages when replacing bulbs as I recall.

Note that an LED fixture normally has difficult to impossible lighting elements replacement. And the voltages are low.
 
The intermatic k4223c is a 208-277 vac rated photocell and should be able to handle both fixtures without a contactor. If you use a 120 volt photocell you will need a neutral which usually won't be available in your scenario and would certainly not be a legal install if you jacked one from somewhere.

But you did say it was for a military installation which means anything goes as long as it works when you walk away from it.:eek: ( no pesky inspectors to worry about.
 

mgookin

Senior Member
A photocontrol certainly is a switch.

You probably don't need a contactor. Can you just have it switch a DPST relay?
 
A photocontrol certainly is a switch.

You probably don't need a contactor. Can you just have it switch a DPST relay?

Are you saying that the photocell cannot be used for the load? Or, that the load is too large to be handled by the photocell alone?
 

mgookin

Senior Member
Are you saying that the photocell cannot be used for the load? Or, that the load is too large to be handled by the photocell alone?
Someone earlier had made a statement that a photocontrol is not a switch. I'm saying it is a switch.

If you are required to break both current carrying conductors, then a spst anything will not suffice, even if that spst anything is a photocontrol.
 

fmtjfw

Senior Member
Someone earlier had made a statement that a photocontrol is not a switch. I'm saying it is a switch.

If you are required to break both current carrying conductors, then a spst anything will not suffice, even if that spst anything is a photocontrol.
The n I guess a thermostat is a switch
 
I would be interested to see the listing for these because they come in something like 1500 Watts for a reason, I would imagine.

And their wiring diagrams show them connected to the load and they only disconnect one side of a line-line single phase installation.
 

GoldDigger

Moderator
Staff member
A possibly important distinction is that since they are an automatic control they could never be used as a disconnect. They also cannot be operated manually (unlike the OFF position of a thermostat) Therefore the motivation for having them open both ungrounded conductors is far smaller.
PS: I have not seen water heater thermostats that open both lines either...
 

fmtjfw

Senior Member
Other discussions:
http://forums.mikeholt.com/showthread.php?t=140123http://
http://forums.mikeholt.com/showthread.php?t=128787http://
http://forums.mikeholt.com/showthread.php?t=115777
http://www.electrical-contractor.net/forums/ubbthreads.php/topics/182189/photocell_requirement_for_meta.html

Two-pole requirement for the Photocontrol for 240V no-neutral appears to be a shirt-pocket rule.

In post #3 I have shown all the "all ungrounded" sections. None of them describe a requirement for all ungrounded conductors to be opened when controlling a 240V LED fixture.

Photocontrols are NOT switches. UL calls them controls. See controls as described in post #7.

UL White book 2013:

Photocontrols, Plug-in, Locking Type (WJFX)
USE
This category covers plug-in, locking-type photocontrols for use on
outdoor-type electric lighting fixtures used for both street lighting and area
lighting (lighting of parking lots and similar applications).
Unless marked specifically ??Tungsten?? or ??Ballast,?? these products are
suitable for use with either type of fixture, rated not more than the rating of
the photocontrol. The voltage rating is 480 V ac maximum.

UL lists photocontrols that open only 1 ungrounded lead for 120, 208, 240, 347, and 480V. 208, 240, and 480 are normally line-to-line rather than line-to-neutral voltages.
 

mirawho

Senior Member
Someone earlier had made a statement that a photocontrol is not a switch. I'm saying it is a switch.

If you are required to break both current carrying conductors, then a spst anything will not suffice, even if that spst anything is a photocontrol.
Yeah, that's my thinking. A switch is a device used for making and breaking a circuit in an electrical connection. That is how a PC functions and that makes it a switch.
 
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