Wire corroded inside insulation

[Patrick Lombard]

What mades a negitive 12 vdc wire corrode inside its insulation? Had a bad ground on my water pump and went to replaced the bad crimp only to find the wire corroded inside the insulation. Kept cutting back to fine clean copper but ran out of wire to cut. The positive wire was bright and shiny.

 

[Windwalker]

Wire should be tinned

If your wiring wasn't tinned (copper looking wire strands instead of silver) then the everpresent water (it's a boat, right) will use capillary action creep up & corrode large lengths of wiring. Theere should be tinned (silver colored) coating on the strands resists corrosion better. Tinned wiring should be exclusively used on your boat. I'm guessing that wire wasn't...

 

[MG]

not strong enopugh connection

Three possiblities, bad connection at the pump or at the other end, water getting inside the wire, or something else drawing ground from this circuit as well. Use heat shrink crimp connectors crimped twice each, or solder with heat shrink tube over, for better conncetions and to keep water out. Is the ground from a decent buss bar or jumpered from something else? Maybe a slightly heavier wire...?MG

 

[Don]

corrosion

It has nothing to do with being positive or negative. Good tinned, multi-strand wire, as Windwalker said, will minimize the corrosion.Not all bilge pumps or float switches comewith such wire.Don

 

[Ross]

It helps to use 3M liquid electrical tape.

I ran a test with 10 ga stranded wire with crimped terminals. one was coated the other left bare. both were dropped into a jar of water with table salt, 10-10-10 fertilizer and left ot soak for about six months. the coated end stayed bright the untreated end turned green.

 

[Benny]

Ross, what's the fertilizer for?

Was that study funded by a grant? Sorry, missed the point; what was the conclusion?

 

[Ross]

Benny I used the most corrosive salts

That I had at hand, far worse than sea water, in an effort to see just how quickly an unprotected connection would go bad and how effective a liquid coating might be. NO! it was not funded and you might do well to conduct some of you own studies rather than indulge in sarcasm. The conclusion was published " the coated terminal stayed bright".

 

[RichH]

That polymer/rubber is 'permeable' ...

Windwalker is right, you need tinned wire. The rubber coating on wires will not prevent water VAPOR and oxygen, etc. from passing through the surface; hence, the surface corrosion on the untinned wire