Hayward Astrolight tripping breaker

[El capitan]

Hello folks. Need some help with my pool lights. Have an inground pool with two 500 watt Astrolights. Pool is around 8 years old. Had to replace bulb in shallow end last year, no problems. Other day I noticed the bulb was out in the deep end. Took out the fixture, it looked dry, maybe a bit humid, but no water. Put the new bulb in. Flipped the switch with the fixture on the concrete just to make sure the bulb worked and the breaker tripped. Didn't expect that. Took the bulb out with the fixture still on the concrete, reset the breaker, flipped the switch on, breaker tripped again. Ok. Thought maybe the GFI breaker is super sensitive and there's some voltage differential because I have two lights and the one light wasn't in the water and the other one was (I know, it's a stretch, but hey, I'm an amateur). Put the bulb in, put it all back together (royal pain to do while floating on a boogie board in the deep end I might add), reset the breaker, flipped the switch, breaker tripped again. Now I have no lights. Remember my shallow light was working when I started this. Took the junction box cover off, it's elevated around 18" above ground next to the pool equipment, everything looks nice and clean and new in there. Disconnected the deep end pool light at junction box, reset the breaker, flipped the switch, my shallow light is back. Checked the deep end light for continuity (the light is reinstalled in the pool at this point) with a multi meter at the junction box, it checks out. I'm baffled. I thought if there was a short in the fixture or the wire I'd have a continuity problem After I did the continuity check just for hee-haw's I rewired the deep end bulb at the junction box again, switch on, breaker trips, no lights. Took it off, shallow light is back. So seems like the issue is somewhere between the junction box and the deep end fixture. The confusing thing is when I first noticed the deep end bulb was out, the shallow light was working and the breaker wasn't tripping. The breaker tripping didn't start until after I took the deep end fixture out to replace the bulb. Is there any way to test the Astrolight before I drop $400 on a new one? If I have the fixture out of the pool, and it's dry and there's no bulb in it and it trips the breaker when I flip the switch I'm thinking there must be a short somewhere in the line or the fixture itself, no? I'm just not sure if having the second light in the water has an effect on my logic? As I type this the one thing I didn't try was unhooking the shallow light and just trying to energize the deep end fixture to see what happens. Curious to hear the forums thoughts.

 

[ajw22]

Welcome to TFP.

I assume your light CB is GFCI.

You are more likely getting a GFCI trip then a short circuit trip.

Show us pics of the light housing internally and externally. How much corrosion is on the light?

And show us pics of the light CB.

 

[El capitan]

Yes, everything is GFCI and bonded. This is a relatively new install an inspected during the process. All worked wonderfully since new. I'll take some pics and post, but there was nothing obvious that I could see with regard to corrosion of the fixture.

 

[ajw22]

As a test you can change the GFCI breaker to a regular breaker to confirm it is a GFCI trip.

You can replace the GFCI breaker as sometimes the GFCI gets more sensitive and false trips over time.

 

[El capitan]

Good idea, I'll try that.