photocell sizing

[mavrck]

I believe it is referring to the LED power supply, and saying your photocell can only be loaded to 50%

I think you need a 10 amp pc for 5 amp sign.

That just seems wise, too. Can you use the pc to control a relay?

I could use a relay but i would prefer to just to use the PC because of location and installation area.

 

[James L]

I could use a relay but i would prefer to just to use the PC because of location and installation area.

If I were doing that job, I would use a relay if at all possible. I would think the inrush of the LEDs will run a 6 amp PC to death. I'd hate to think you might be back every few months swapping it out

 

[GoldDigger]

If I were doing that job, I would use a relay if at all possible. I would think the inrush of the LEDs will run a 6 amp PC to death. I'd hate to think you might be back every few months swapping it out

Some LED drivers have substantial inrush, some do not.

 

[James L]

Some LED drivers have substantial inrush, some do not.

I think they've all got enough that loading a photocell to 85% is asking for trouble

 

[Russs57]

Thanks for this post. I didn't know photo controls needed a LED rating. I just assumed the LED fixtures were so much lower in current than the old lights they replaced I didn't need to think about it. Not what was it they said about assuming?

 

[dpcarls1598]

I‘ve had single wall packs ruin a non-LED rated photocell many times. They claim to switch at the zero reference to avoid the large inrush and it seems to work. I have some lot lights that total 5.7a at 277v and the 6a photocell has worked perfectly now for 5 years. I put it in as a temporary solution until I could get a rated enclosure for a contactor and the enclosure is still sitting on my shelf for the day it fails. Of course now that I said this...

 

[James L]

Thanks for this post. I didn't know photo controls needed a LED rating. I just assumed the LED fixtures were so much lower in current than the old lights they replaced I didn't need to think about it. Not what was it they said about assuming?

Kinda same as a universal dimmer...
Rated for 600 watts incandescent, but only 150 watts LED. It's because of inrush

 

[mavrck]

Thanks everyone for the help. After reading everyone's opinions and searching through code gave me some good incite. I agree 110.3B calls out use equipment for what is listed for such as PC for outdoor lights , signage etc. 401.14 does not specifically call out PC but does say only load switching devices to what they are rated for. 600.6b calls out switches , flashers, etc. shall be rated for inductive loads or have current rating twice the load.
With all that being said in this situation i feel as long as your PC is rated for the load you are abiding by code requirements or using a PC for a contactor coil is also a viable option.

 

[LarryFine]

One can understand why some are confused that a 6a device can be used to feed a 5a load on a 20a circuit, but #14 wire can not.

 

[mavrck]

One can understand why some are confused that a 6a device can be used to feed a 5a load on a 20a circuit, but #14 wire can not.

are you referring to the PC wires? If so what would you suggest?

 

[mavrck]

One can understand why some are confused that a 6a device can be used to feed a 5a load on a 20a circuit, but #14 wire can not.

That does bring up a good question how are the wires on dimmers, PC, and other switching devices viewed per code that are on 15 and 20 amp circuits? typically they are 16 or 18 gauge. Haven't thought of it.

 

[LarryFine]

are you referring to the PC wires? If so what would you suggest?

No, I was only using the photocell discussion as an example. I'm referring to people who wonder why it's not compliant to, for example, use #14 between a switch and a single light on a 20a circuit.

 

[mavrck]

No, I was only using the photocell discussion as an example. I'm referring to people who wonder why it's not compliant to, for example, use #14 between a switch and a single light on a 20a circuit.

I agree it does get confusing at times .