This is not the first time I've ranted about the previous owner's wiring jobs, though I think they were on the other site (and I had a different username there).
His greatest hits include:
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Above a drop ceiling in the basement, a wire that went into a metal box without a strain relief, so it eventually wore through (for whatever reason) and started shorting out. Since it was above the drop ceiling I had no idea why that breaker would occasionally trip, then reset without complaint. Also, there are other things on that circuit, but the offending wire was only live when the light switch in the room was on, so it was harder to diagnose. It wasn't until we demolished the room that we found the problem...black marks on the box and wires and all.
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A duct fan to route heat from the pellet stove into the master bedroom...with the wiring completely enclosed in the ceiling, with no access to the box. Said duct fan has started making noise, so I'm going to have to cut that ceiling open and replace it, and I'll probably install one of those spring-loaded covers so there is access in the future.
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A fascinating wiring job in the shed that is unnecessarily complicated and certainly a violation of the code on how many conductors can be in a box. I'm going to fix that some time this spring. This is actually a REALLY great one, so maybe I'll post it as a comment.
On to today's hilarity. A few weeks ago I noticed the UPS for my computer in the basement had a red light on the back warning of a wiring fault. I never noticed it before, or I did and forgot, and it's not very bright, so you almost have to be looking for it to see it. Well, I got out one of those testers that you plug in, with three lights that diagnose the issue, and it showed no ground. Odd.
I checked the other two outlets on the same wall, the one closer to the panel tested fine, but the one on the other side of the outlet in question also showed an open ground.
Today I dug in to find out what was up. It turns out the ground was cut on both wires in the outlet the computer was using (supply from the previous outlet and the wire to the next outlet). It was not connected to the metal box or the outlet.
WHY WHY WHY? Why did he do this? I can't fathom why you'd do this.
I replaced all three outlets on that wall with new ones and made sure the grounds were connected. Nothing really wrong with the original outlets and covers, but they were old and beige, and I like white.
Years ago I found an outlet in our closet that only had two prongs, no ground. The house was built in 1987, well after three prongs were standard. With some trepidation - what am I going to find here? - I opened it up and found that...there was a good ground there (to my relief) but he apparently just decided to use a two prong outlet. WHY? He had to have gone to special effort to find a two prong outlet to install. (Actually it is theoretically possible that was done by the builders, but everything else in the house is three prongs, and I can't believe it would have passed inspection.)
For the shed wiring job...
First, switch wiring. Normally when you wire a light switch, you have your 14-2 (or 12-2, or whatever, I'll use 14-2 but the gauge isn't really relevant) coming into the box, then another 14-2 wire leaving the box, and the two black (hot) wires are connected to the switch. A sequential setup, if you will: Power, switch, light. A simple diagram.
However, in certain situations, it's more convenient to run only one 14-2 to the box. For example, you might do this if you have a supply of constant power at the light fixture, but no source of constant power near the light switch. So, you bring the supply 14-2 into the box, and then use a single 14-2 to run to the switch. The black wire is connected to the supply at the light and one terminal of the switch, and then you connect white to the other terminal of the switch, and back to the light in the first box. You are supposed to mark the white on both ends to indicate it is being used as hot rather than neutral. Here's a diagram of the setup.
I think of it as a giant T - supply power comes in the top left, light is on the top right, and the vertical line is the wire to the switch that carries supply hot and switched hot on the "wrong" wire. It's useful when there's no power source near the switch, but there is power at the light fixture it controls.
Note that in the box at the light, you'd have three 14-2 wires coming in (6 conductors plus 3 grounds) - supply, power for the light, and the run for the switch.
Okay. It's like the previous owner of our house learned this trick...and wanted to use it everywhere.
So, there's a box in the shed that has:
So, I have 6 sets of wires coming into this box (hot, neutrals, and grounds). Oh and on at least one of them, he switched the neutrals, not the hots, so there are white wires serving as hot (unmarked, naturally) and who knows what else is going on. At the very least it's a violation of the code for the amount of conductors in that size of box.
The worst part, though: It wasn't necessary.
It's insane. I'm going to redo it soon, and I don't think I'll need to buy ANY supplies to do that. In fact I bet I'll have extra wire when I'm done (I may need smaller wire nuts, which I have already).