Underground Copper Wire Green?

Question

Hi,I'm having intermittent problems with an exterior post lamp (lightsometimes works, sometimes doesn't and it's not the bulb). I pulledback the wire from the fixture itself through the post bottom, butdamaged that run while removing (~6'). Upon cutting and stripping thatlength back at ground level so I could splice in a new wire into thepost (using an underground splice kit to mate the old/new), I noticedthat each copper wire of my existing wiring (black, white, ground) hasa green coloring such as you'd see on copper roofs exposed tomoisture. I'm guessing that water's penetrating which might explain myintermittent problem, so I've halted my repair at the moment.Does underground wiring normally turn green, or is water somehowpenetrating where it shouldn't be? House is 15 years old. Thanks!

dpb · Accepted Answer

...No and yes, sounds as if...Good chance the original was pulled using ordinary romex used for the rest of the house rather than underground-rated cable.Best guess from here is you're best bet is to pull a new cable using U(nderground)-rated wire.You could try the repair and perhaps get by for a while but it's going to fail completely sooner rather than later so the effort w/o the replacement would likely be more futile than not...--

John Grabowski · Answer

Green is an indication of moisture infiltration. As a result there may be a section of the cable that is arcing between conductors which may explain the intermittent problem. Normally UF cable does not experience moisture problems unless the outer jacket has been compromised. However if the cable is regular type NM (Romex) then that would explain everything. If it is Romex you should replace the entire run.

Underground Copper Wire Green?

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