Photocell shorting cap

[Vertex]

Does anyone know if a twist-lock photocell shorting cap with overload protection is made? If I can't find one, I was thinking of making my own with the following parts.

 

[fmtjfw]

Looks like an easy to make tool.

Do you often run into shorted fixtures?

Do you trust the "fuse-breaker" on voltages higher than 120V?

 

[Vertex]

I have run into shorted fixtures.

Would you rather use an unprotected shorting cap or one that is technically only rated for 120V?

 

[iwire]

I have run into shorted fixtures.

Would you rather use an unprotected shorting cap or one that is technically only rated for 120V?

Considering it could explode in my hand as I installed it I would probably avoid either.

 

[Vertex]

I've had a photocell blow up in my hand. That's the point of finding/creating a solution.

 

[fmtjfw]

I've had a photocell blow up in my hand. That's the point of finding/creating a solution.

I'd go with a 600V inline fuse holder if I were going to use it for more than 125V.
I'd also wear a class 0 or 1 rubber glove w/protector, eye protection, and an FR shirt.
I assume this is for commercial rather than utility work? Utility is likely to have much more available fault current than commercial.

Work safe.

 

[Vertex]

I like all of your ideas. Thank you!

 

[mgookin]

If you could have this in any specifications you want, what would those specs be?
Just curious, what are you doing with it? I'd think the circuit already has OCPD before a twist-lock receptacle.

Does anyone know if a twist-lock photocell shorting cap with overload protection is made? If I can't find one, I was thinking of making my own with the following parts.

 

[fmtjfw]

If you could have this in any specifications you want, what would those specs be?
Just curious, what are you doing with it? I'd think the circuit already has OCPD before a twist-lock receptacle.

Utility applications I'm familiar with, just hook the fixture (and the photocell socket) to the closest secondary. There may be a primary fuse but nothing coming close to the NEC value for protecting secondaries and certainly no secondary fuses.

Don't know much about underground street/highway applications, but I believe they usually have a fuse per lightpole.

240, 277, and 480 distributions for parking lots are typically fused, but still have some "punch" to them.

 

[Vertex]

I find it somewhat interesting that no one else has asked this question. The purpose of the device is for safely bypassing a photocell. IMO, the safest way now would be to deenergize the circuit, replace the photocell with a test cap, and then reenergize the circuit. For a single person, this can be quite time consuming considering the trips from the panel board up to the luminaire. I had a situation in a parking lot where many ballasts were burned out and in the shorted state. I think this may have led to the photocells also being defective. Before opening the luminaire for inspection, I attempted to replace the photocell with a new one. Because of the shorted ballast, the twist-lock plug and the receptacle did not play nicely when contact was made.

Ideally, a testing device would be made to withstand a fault. Perhaps a momentary switch would control a latched relay only after the cap is locked in place. The device would have a breaker for easy reset.

 

[mgookin]

I find it somewhat interesting that no one else has asked this question. The purpose of the device is for safely bypassing a photocell. IMO, the safest way now would be to deenergize the circuit, replace the photocell with a test cap, and then reenergize the circuit. For a single person, this can be quite time consuming considering the trips from the panel board up to the luminaire. I had a situation in a parking lot where many ballasts were burned out and in the shorted state. I think this may have led to the photocells also being defective. Before opening the luminaire for inspection, I attempted to replace the photocell with a new one. Because of the shorted ballast, the twist-lock plug and the receptacle did not play nicely when contact was made.

Ideally, a testing device would be made to withstand a fault. Perhaps a momentary switch would control a latched relay only after the cap is locked in place. The device would have a breaker for easy reset.

So something with the same load rating as the photocontrol would suffice?

To make one for yourself should not be that hard.

To manufacture one for the public would mean it would have to withstand the same environmental conditions, etc. as any twist-lock device. It would have to be expected that someone's going to leave it out there during a storm, etc. It can be done.

 

[fmtjfw]

The twistlock used by photocells is non-NEMA. Hubbell sells a plug that is the same as a photocell: HBL7567C. That and an inline 600V fuse holder (and fuse) would make a handy, durable test "shorting cap".

The plug pattern was a 15A 125V / 10A 250V grounding (photocell application uses "grounding" pin as neutral). NEMA appears to have no dual rated voltage plugs (a plug for either 125 or 250V). I came across a non-dead front version of the plug while looking for odd plugs in my collection of stuff.