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MEXANDME
04-18-2010, 12:44 AM
Customer called tonight stating that part of her lights were out.

I go over and one of the two circuit breakers was tripped (600W Vista MT).

Reset it and it tripped again within 2-3 seconds. There are 3 leads on this circuit. I unhooked, hooked back up, etc. until I isolated which of the three leads was causing it to trip.

I took the bulbs out of the 3 fixtures on this lead and hooked the lead back up. It did not trip.

I put the bulbs back in one at a time until all 3 were back in. It did not trip.

I waited about 20 minutes and it did not trip.

Any ideas what the problem was? If the circuit is overloaded ( let's say 320 - 350 watts), and I do not know whether it is or not, would that cause it to trip later than the 20 minutes that I waited?

Any ideas, thoughts, suggestions, etc. is appreciated!

Regards,

Mex

steveparrott
04-18-2010, 11:06 AM
Something funny going on here. If you only have three fixtures on a run, how could they amount to over 300W? Sounds more like a short.

You isolated the problem to the one wire run - meaning that the breaker immediately tripped when only that wire was connected - then you took out the lamps - no tripping - then you replaced the lamps - no tripping.

The most likely scenario is that the problem is at one of the fixtures. Maybe an intermittant short at the socket that you temporarily fixed during relamping. Perhaps a corroded socket or socket wire. Inspect the three sockets and their connections.

Less likely is a short or corroded connection at the transformer's terminal block - either at the field wire side or the internal wire side. Check for blackening of the terminal block and wires that enter it. It's also possible that the wires entering the top of the block have come loose and are contacting other blocks.

The Lighting Geek
04-18-2010, 12:32 PM
Steve is right, I found the same problem on a system I did not install and it turned out to be a cracked wire casing in the stem of a path light intermittently shorting.

MEXANDME
04-18-2010, 05:58 PM
Steveparrott,

This one lead has 3 50W lights. There are 3 leads (including this one) with one side tied down on the two C1 lugs of the transformer that may or may not be exceeding the 300W limit (I did not install this system. I design for 250-260W per 300W circuit).

The problem may, in fact, be an intermittent short in one of the fixtures or even the wire. I will take a closer look on Monday.

The more I think about it, I do not believe an overloaded circuit is the problem in this case. Because when I got there, the circuit was tripped and WOULD NOT reset. Everything was "cool" temperature wise. Once I pulled the 3 bulbs, it would reset. I put the bulbs back in, one at a time, waiting a couple of minutes between bulbs, and all bulbs stayed on and the circuit did not trip. I monitored it for about 20 minutes. Like you said, there must have been some sort of freak short that cleared itself when I pulled the bulbs. I guess it may or may not "show it's ugly head" again!

Thank you both very much! It is comforting to a "relative rookie" like me to have guys like you who are willing to share your knowledge!

Regards,

Mex

Pro-Scapes
04-18-2010, 06:12 PM
Just curious. Why would a single run trip both breakers ? It should have only tripped the breaker in which the faulty run was attached to.

You can try the wiggle test. Wiggle the sockets and connections and see if you can replicate the short. It definatly sounds like you have an short someplace.

MEXANDME
04-18-2010, 07:28 PM
Pro-Scapes....it did not trip both breakers....just the one to which it was connected.

I will try the "wiggle test" on Monday.

Thanks!

Mex

INTEGRA Bespoke Lighting
04-18-2010, 11:02 PM
Yep, sounds like a short at the socket or fixture stem or perhaps at the fixture connection. What make are the fixtures?

David Gretzmier
04-18-2010, 11:44 PM
I have sound similar issues at the base of sockets. many have bare wire behind the socket, with insulation that has worked loose, and the wires cross causing a trip of the circuit breaker.

Pro-Scapes
04-19-2010, 12:20 AM
Pro-Scapes....it did not trip both breakers....just the one to which it was connected.

I will try the "wiggle test" on Monday.

Thanks!

Mex

Sorry I misread. My mistake. You said one of the two not two. My apologies.

MEXANDME
04-19-2010, 08:21 AM
James....it is a Vista 2216 bullet.

Thanks,

Mex

INTEGRA Bespoke Lighting
04-19-2010, 08:40 AM
James....it is a Vista 2216 bullet.

Thanks,

Mex

Check the lead Wires all the way through the stem of the fixture. Sometimes they can get pinched or stripped and cause a tempermental short.
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MEXANDME
04-20-2010, 07:52 AM
I tried the "wiggle test" today and closely inspected all 3 fixtures. Did not find anything.

This customer keeps a close eye on her lights. So, if it fails again, I will know right away.

Thanks again for everyone's help!!!

Regards,

Mex