Success Repairing Another Short Circuit

New wall electric box

New electric box with one new wire the other goes to the light in front of the garage

I did it! I finally fixed the short in the front lights. It took a lot of disentangling of wires and trying to understand triple switching etc. but in the end the issue was just a bad wire to the light box. I had to pull another one.

The good news was that it was accessible without destroying the stucco or figuring out how to cut at just the right spot in the garage ceiling. The bad news is that it required that I climb up into the space that is between what I think is the garage attic firewall and the outside siding. It is just barely big enough to scoot along and of course there are nails hanging down and through the siding just waiting to prick a head or arm. Also even though it is a mild day it was super hot–I had to breath through my shirt sleeve to keep the dust out of my lungs when I first disturbed it. I was pretty wet from sweat by the time I emerged.

These are wires in the space. Four wires go down into the switch box in the garage wall next to the door. One controls the garage lights, and two others have been disconnected. One may have powered a light in the entryway. The other may have been a triple switch wire as it has four wires. I’m not sure how the wires got grease on them. That is the black areas on the wire.

Bad wire at left

Bad wire at far left other wires go to the switch below.

In the upper left quadrant of this photo you can just see where the wire goes into the garage wall insulation to the outside light box and then a wire comes back up and continues to the garage outside light and on to the post lights in the terrace wall.

Bad wire was removed

Replaced white romex wire that goes down through the garage wall  to the light fixture

I had no idea how to figure out where the short was. I had the circuit down to just one wire and when I connected it, the circuit breaker blew. Everywhere I could see the wire looked just fine. But I read on the internet that a short is caused by either an open neutral or a connection between hot and ground–short to neutral or short to ground. The test whether to tell if the short is to neutral in the wire is to wire ONLY the hot side. Then if the white and/or ground wire are also hot when the breaker is turned on–and the breaker does not trip, the fault is in the neutral wire or ground wire. Doesn’t matter which as it means the whole wire has to be replaced.

It was difficult to find the help I needed for this problem. One reason is that most of the electrical troubleshooting tips stop at the most rudimentary testing. The other is that hire an electrician is too often the answer to even the simplest of problems that put a do it yourselfer in no danger at all. Yes, an electrician can fix your problem faster than you can. We know it, but that that does not make it practical to hire an electrician for every little wiring issue.

A book I found on Google Books had the answer. It was Circuit Down by Larry Dimrock from 2007. He also has a website called Circuit Detective. The text is a little difficult to understand at the troubleshooting page. And the information is only partially available on the website–it “disappears” after 30 seconds, and for $10 you can buy all the information currently on the website.

There is a link to the ebook version for $5. The ebook format is of the print book that is on Google Books. Since I found the information so helpful, after I solved the problem I bought the rest of the ebook–finding a coupon for 25 cents off. From the Google books version,  I found this hint on page 68 for testing for an open neutral or ground fault.

The matter of whether it is the neutral that the hot is shorting to is best determined by disconnecting that circuit’s neutral from the panel’s neutral bar, capping it, and seeing that the short is then gone. An ammeter clamped on the hot wire at the breaker or fuse can also confirm that it is tripping/blowing for high current. Clamped on the circuit’s neutral, it would also show that the circuit is indeed running hot-to-neutral.

Instead of disconnecting the neutral in the box, I just hooked up the black wire to the lights and left the white and ground unconnected and even uncapped and the circuit breaker did not trip. With my circuit tester–I have one of those beep on hot–it showed that the neutral (white) was as hot as the black, as was the ground. So somewhere in that wire the hot was touching the white and the ground and breaking the circuit.

The wire was tightly fixed inside the wall, so I had to run an new wire and cut the old one off. I used a wire puller tape that I bought some time ago at Harbor Freight. It worked pretty well but I had to make the hole in the top plate larger to fit the new wire through. The old wire was taking up space and we couldn’t pull it either up or down. It is stapled somewhere in between, probably enough to have broken the wire.

I installed a switch for the two front lights and will think about tying in the third or will put it on its own switch. Tomorrow I will try to re-install the lights! And I can add to the list that the area between the garage attic and the outside wall needs caulking and spray foam to seal small openings to the house ceiling and walls.

New switch

New switch

Today I filled in the perimeter of the junction box with spray foam and installed the lights.

Foam insulation around box

Foam insulation around box

The porch light has a function that allows it to dim for several hours at night as accent lighting. This didn’t seem to work very well with the LED bulb that is supposed to be dimmable. I just put the bulb that it came with back in and will see if I can get a setting that works with the LED bulb later.

Re-installed porch light

Re-installed porch light

The rewire of the garage carriage light is a little funky with the bulb at the very bottom of the light. The bulb holder is designed to swing–I guess to change the original candelabra bulbs. I used an outdoor socket but it didn’t have a mount at its neck so it is hanging from the old light holder. But it also works for now–I want to paint this light dark copper like the others eventually too.

Re-installed garage light

Re-installed garage light

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