Pool Light Voltage Problem-V.drop?

[Lightning]

Pool light 120V ok but Spa light would come on and off, now off altogether. Found Voltage drops to 60V at the light but 120V at the junction box? Anyone know what could cause V drop? Bulb checked ok. Could the overheat coil cause this and what to do?

 

[JohnT]

Welcome to TFP.

Is the voltage drop the same with the light on and off?

 

[Sparkmaster]

Sounds to me as a lost neutral.. See if all connections are good and if so, The neutral may need to be replaced..

 

[Lightning]

There is no voltage when the lights are off at switch--and when swith on there are no spa light and 60 volts to 80 volts. Ground/common seems to test ok.

 

[Poolsean]

Don't you have a transformer to the light? Is this an inground spa or a portable?
Most lights us a transformer and drops the voltage down to 12 volts. Older pools allowed 120 v directly to the light.

 

[Lightning]

Thanks so far but no solution! No transformer as older system with 120 to the lights. Voltage ok at the switch and the junction box for the in ground spa.

 

[sjoefl01]

I have been fighting a similar problem for a couple of years now and finally solved it this weekend. The problem was oxidation on the bulb contacts. I wire brushed them and applied a spot of alumilox to the center pin contact and coated the threads. You need to be careful not to gob the stuff down in the socket. It is conductive grease and you can cause a problem if you create a path for current between the contact and the threads.
Your 60 volt reading is strange. That may be something else. If you are taking the bulb out of the socket and measuring there you should have no voltage drop because you have no load on the circuit. The only way this could happen would be if there was some parallel path for current. I don't know exactly how the overheat coil is connected in the circuit. Perhaps it draws some current and you have a poor connection in the line that is dropping the voltage. If that is what is happening then there should be some heat generated at the bad connection. If your light holder is like mine then everything is potted so you really can't do much with it except the bulb.
Whatever you do be careful dealing with this 120 V light around the pool. Don't work alone. When I am working with suff like that I use one hand as much as possible. I tie a rope to it and give the end to my wife so she can pull me off if I get hung.
Keep us posted on your progress.