10-05-2012, 09:38 PM
Joined: May 2007
Location: San Francisco Peninsula
Electrical No-No! Have I analyzed/fixed correctly?
Was going to do some things to the electrical system so took off the seat and removed the cover of my Centec AP-2. When I looked at the positive switched connections I noticed ‘gunk’ on top of the tightening screw; then noticed a burnt smell and discoloration on the last two wires. They went to the relay for my Hella DE Fog lights (which has a lighted, push-button switch in the left hand guard). I did not take the pictures below until I had removed and separated the two wires (red power; blue trigger).
The Hella’s and the Centec were installed 4+ years ago. The relay had a twisted copper red wire (not sure of gauge, but probably at least 12) and a small blue relay wire (maybe 18 gauge). I did not want to find and tap into any headlight wires (I was brand new to this bike, and as I guess is obvious, to installing my own fuse block). Since the Centec itself is switched, I figured that I could attach the blue relay trigger wire to one of the positive terminals as well. Since it was only supposed to draw enough to trigger the relay (milli-amps?) I thought I could just “pair it up” with the red wire. I put the blue and red wires side-by-side, wrapped some black electrical tape around them, and inserted the pair into the terminal for fuse #4. It had a 10 amp fuse.
It has remained this way, even through other additions to the Centec, most recently my Garmin Zumo installation 18 months ago. Certainly the fuse block did not look like this at that time. Also, the lights were still working at the time I discovered this.
I removed the wires from the terminal block. I did not have to loosen the screw. Actually, I did not know there was still a screw there until later when I cleaned out the ‘gunk’ in the recess. I removed the black tape and discovered that the insulation had gotten hot enough for the two wires to stick together. The ¼ inch of insulation at the end of both wires was black. I used a utility knife to separate them, leaving some blue insulation on the red wire and exposing some of the blue wire in the process. The two wires themselves had not come in contact. However, the red wire had ‘blistered’ somewhat, and there appeared to be 1 or 2 ‘pin-head’ sized holes that exposed some wire.
So what happened here?
I am assuming that the current in the red wire heated the blue wire as well (duh) since they were both attached to the same 10 amp fuse, probably more than the blue wire should be exposed to safely. I assume that there was some resulting temperature gradient along the blue wire for perhaps a half-inch or so. But it was enough to overheat the insulation and cause the two wires to stick together. Once that happened, the heat just might have gotten worse, or ‘other things electrical’ may have begun to happen as well.
I’m guessing that I was lucky that I did not have a fire.
What I have done is strip the bad insulation from both red and blue wires, attached the red wire to terminal #3 with a 10 amp fuse, and attached the blue wire to terminal # 5 with a 3 amp fuse. Am I OK now?
Thanks. And all comments related to my stupidity will be read, at least twice.