MC Puncture Outdoors

bwat

EE
Location
Western PA
Occupation
EE
Almost more of a survey of your guesses based on your experience..

If there’s some MC cable outside with a rather small puncture through the sheath that was causing an intermittent short, how likely is it that enough water/moisture got in the cable that it damaged the cable to the point that the whole thing should be replaced?

The puncture area has been spliced/repaired, but we’re still seeing some odd behavior possibly related to another short. Since I don’t visually see any other issues, I’m leaning toward recommending that the whole cable be replaced.

Best estimate is that the cable has been damaged for about a month before being fixed.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Thanks. To clarify, it is jacketed MC since it’s outside. Still not a fan for outdoor use? It’s run up along a steel structure so it seemed like a reasonable choice for me.
That it has been damaged already suggests to me that it's not tough enough for the environment. RGS (rigid) would be the best choice. If you need flexibility, I would recommend using LFMC (Sealtite) instead. You can also use conduit for the straight runs and flexible at the ends.
 

bwat

EE
Location
Western PA
Occupation
EE
That it has been damaged already suggests to me that it's not tough enough for the environment. RGS (rigid) would be the best choice. If you need flexibility, I would recommend using LFMC (Sealtite) instead. You can also use conduit for the straight runs and flexible at the ends.
Ah ok. I thought it was just a general dislike for jacketed MC outdoors. You make good points and I would agree now.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
MC is pretty tough. If it is being punctured, I would wonder what could be doing it. Just being outside is not going to do it. Has it been installed so that it is not able to flex enough during periods of temperature change? Is there something rubbing against it or hitting it? Is someone deliberately damaging it?
 
Top