Large wire damaged by heat from soldering pipes.
How Dumb Can A Guy Be?

So... how did I manage to burn through this big cable?

In This Article:

An explanation of things done wrong.

Related Articles:

By , Editor


Well, it was kind of stupid, actually. I was doing some plumbing work... running a new pipe to replace an old section of supply pipe in the basement of the old house we've been remodeling.

I had to solder some joints up close to the floor joists, right where the joists rest on a wood beam. So there was wood all around the area. I employed several pieces of thick sheet metal for heat shields. With these shields, I found that I could let the torch flame touch the metal for a few minutes with no burn damage to the wood. In the back of my mind I was thinking about how many times I have heard of major house fires being started by a plumber's torch.

Now, there are heat shields made for this purpose. But I don't do that much soldering work, so I figured I could get by with my steel scraps. I have done a few dozen soldering jobs with these, with no problem.


In one place, there were a couple of wires above the joint I had to solder. I stuck my L-shaped piece of steel above the pipe, so it propped the wires up, away from the heat.

I soldered the joint, and just as I was finishing... KAPOW...a big flash right before my eyes. My first thought was that my propane torch blew up. Then I somehow stumbled backward from the small step-stool I was standing on. Miraculously, I didn't trip or fall backwards, nor did I drop my torch.

My mistake immediately became apparent: The L-shaped heat shield, positioned like a tent with the cable resting on it's peak, had gathered heat and funneled it to the top. The heat had concentrated at the top, which melted the cable insulation, causing the live wires to contact the metal heat shield, and then short out.

And there was not one flash, but two, about one second apart. The circuit breaker did not trip with the first arc. Since I was installing new copper pipe, it was not yet connected to the system, nor was it tied to the electrical grounding. So the new pipe may have been momentarily energized, which could have caused another person to receive a shock if they were touching the pipe. But there was nobody else in the house (which is yet another hazard). 

There are many things I could have done differently, including purchase a proper heat shield. 

I'm getting more knowledgeable all the time. I hope you are too.


"Experience is something you don't get until just after you need it"  (Steven Wright)


Hey, just for kicks, you should read our disclaimer. Just in case you get hurt, we want you to blame yourself completely. It's the "in thing" these days.



Back To Top Of Page 

Before You Hurt Yourself,  Read our Disclaimer.

Search Page

Home  What's New  Project Archives  H.I. World

 Rants  Contact Us






Copyright © 2000, 2005

Written May 31, 2000
Revised January 7, 2005