Found out romex staples can cause shorts if you drive them too deep

Was working on a recessed light retrofit in a client's attic in Phoenix last Wednesday. I was pinning down some 12/2 and thought about how tight I was hammering those staples in. Looked it up later and apparently if you crush the wire with a tight staple, the insulation can break down over time and cause a short. I've been zipping them in tight for years without thinking about it. Anyone else ever deal with a service call where a staple was the culprit?

3 comments

3 Comments

kim_patel898d ago

Heat from the current finally made a crack" - was that in Phoenix summer heat too?

verap528d ago

You know, what you said about crushing the wire got me thinking. I had a call back in '19 where a homeowner was complaining about a flickering light in their kitchen that would just cut out after a few minutes. I pulled the switch and it looked fine, checked the fixture and that was okay too. After a solid hour of scratching my head I finally started pulling the wire out of the wall near the staple. Sure enough, that one staple was driven in so deep it had mashed the romex flat as a pancake. The insulation wasn't broken right at the spot but it was thinned out, and over time the heat from the current finally made a crack and a short across the hot and neutral. Why do we always learn the hard way with stuff like this? The worst part is that same staple job was done by a guy who bragged about his hammer work.

hugo_jones8d ago

Honestly @verap52 that story about the flickering light is wild. Never thought about the heat from the current being what finally breaks it down, I always figured the staple did the damage right when you hammer it in. Where they used those plastic romex staples or the metal ones?