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Wire Corrosion

JC Lighting

LawnSite Member
San Jose, CA
Yesterday I was replacing lamps on a job that was done by a contractor 7 years ago. The sytem was mostly Unique well lights and transformer. The wire at the Hub connection and at the transformer was totally black. The Hub had a non-copper connector without any dielectric corrosion preventing grease or silicon etc. and not the typical barrel lug and Oxgard grease used in a Unique Hub. The connector was disintegrating and one of the them was hot to the touch while under power. I have seen many other lighting systems with excessive corrosion in the past with adequate voltage to the lights and seemingly functioning well. However, eventually these non protected systems must fail. I've got my guesses but I'm looking to have them validated. Has anyone actually seen a failure from long term exposure to the elements without corrosion protection and what does this failure actually look like and what, if anything short of changing out the wire, can be done at late stages of corrosion to extend the life of the system?

Jim C.


LawnSite Member
So. Cal
Recently ran into a similar situation and during a converstation with a buddy of mine and asked roughly the same question...... His insight is moisture whicking up the line in some cases 20' or more, in other words fatal mistake to whack off a couple fit of the exposed and fire the system up. From that entire system I fired up I only got one read on one lamp, all the other runs were dead.


LawnSite Platinum Member
just seen it yesterday. Someone buried a metal junction box and used romex clamps then reg wire nuts to join romex and a short fixture lead. The jacket of the romex was melted a bit. Gotta rebore the 30ft driveway to correct it now. Since it was installed the property was regraded and about 3 feet was added to this area to create a raised area.

Same property wires were burried around the root ball of ball and burlap crepes... 5 years later the roots now own the wiring. Client doesnt want me to rewire the front til it fails because (well its been esentially trouble free for 5 years)

Ok thank you now sign this waiver that im not liable for the existing system and call me when it fails.


LawnSite Senior Member
While troubleshooting a job where a number of fixtures were not working I discovered a wire at a T-connection that was discolored and didn't look right. I had a bad feeling that it was not just at this connection. So I went on down the line diconnecting each fixture and then went back with a new fixture and bulb trying it at each connection point and then the next. I got a volt reading at each connection that is until I tried wiring in the new fixture. When I did this it killed the juice all the way back to the bad looking wire. Hmm....... I then temporarily wired in a new piece of 10/2 as a jumper wire in place of the suspected bad section and tried the meter readings again.......bingo! It was a good troubleshooting lesson for me.