photocell problem

[George Stolz]

Re: photocell problem

P.S. I had a house fail today because I never realized the back outdoor outlet was required to be accessible from grade level. I had it on the back deck, below 6.5' from grade, but caged in.

So, yeah, three cheers!

 

[ghelec]

Re: photocell problem

Thanks to everybody for the input. Thanks Hurk for the info on the Intermatic. I ordered him one today and will try it,bet it will solve his problem. Figured out why the former electrician wired the other light on 240,splits the load,one leg of 240 is hot straight thru and the other goes thru the photocell. Not very good way to do it but works I guess.

 

[George Stolz]

Re: photocell problem

I'm pretty sure that even that way, the photoeye is trying to run 240 instead of 120. It'll work for a while, but it'll croak pretty quick.

 

[hurk27]

Re: photocell problem

ghelec
If 240 volts is used to feed the fixture then ether a 240 volt photo cell has to be used or a relay type as I posted. A 120 volt thermo type photo cell passes some of the current drawn by the fixture through a heater element that the photo element is in parallel with as the light goes down the heater element cools off causing a bi-metal plate to bend and cause a set of contacts to close. This is why there is a delay on them. But if 240 volts is passed through one it causes more current to flow and causes the photo cell element to burn up.

 

[hurk27]

Re: photocell problem

I'm pretty sure that even that way, the photo eye is trying to run 240 instead of 120. It'll work for a while, but it'll croak pretty quick.

George Yes a 120 volt thermo type will fry when a 240 volt load is placed across it, but a relay type wont have that problem as the relay has to have a neutral to it's white wire. The photo cell and coil is only connected between the neutral and hot, the load is connected to the isolated contact on the output side of the relay (N.O. contact) No different from using a 120 volt relay to start a 480 volt motor, except the photo element is the start button.

Here is the diagram for the Intermatic 1121:


[ May 10, 2005, 01:53 AM: Message edited by: hurk27 ]