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My parents inherited a house and I'm just kind of cleaning it up. It's old -- Edison fuses and other things that I have to puzzle over.

Replacing a damaged beige four-outlet thing in a bathroom, one of the switches is weird. Beyond the already seemingly unreasonable gauge of wire being used (that can barely fit in the screws without popping out), the switch for the fan has two wires connected to the bottom. And the other wire goes into a hole at the top instead of the screw:

weirdo switch

What... is this about? The nice new white switches to match the new ceramic faceplate do not have the hole at the top; just the screws.

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I believe that connecting two wires to one screw terminal is a no-no. –  Alfred Centauri Nov 21 '13 at 14:50
    
@AlfredCentauri Yeah that's what freaked me out until I realized that it's a single wire, stripped in the middle as a loop. As I mentioned below it's not my house, everything is weird and amateur and 50 years old, and I am proceeding with caution before I touch things. Intuition and sanity doesn't necessarily fly here. It's a miracle this place hasn't burned down. –  HostileFork Nov 21 '13 at 14:55
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4 Answers

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The hole is simply a different way of connecting the wire. There is a spring-loaded contact inside that also works like a ratchet by making it harder to pull the wire out than stick it in. This is all intended to minimize the time it takes to install the switch. Some have these, some don't.

Also, the wire size doesn't look absurd at all. That's probably 16 guage, maybe 14, which is totally appropriate for stuff like simple lighting fixtures or a bathroom fan. Of course the fuse this is on must be rated for the minimum wire size used anywhere on that circuit. I don't see anything out of the ordinary here.

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Thanks for the info. I hadn't unscrewed this one because it was odd to me. But when I did the gauge on this particular one is fine. (as I should have noticed since two wires were able to fit on the screw, while the others can't hardly fit one wire). But why the two connections? Does that actually accomplish anything to tie to (presumably) ground? If you know it's ground, why not just tie ground? –  HostileFork Nov 21 '13 at 14:34
    
Also, I don't really care for the insertion idea. You have to cut the wire to get it out, as far as I can tell. :-/ It reminds me of all the other bad ideas in this house, like seeing paint on fixtures that nobody removed during the painting or masked. –  HostileFork Nov 21 '13 at 14:42
    
I should have unscrewed it, it's not two wires at all, it's just one! They stripped it in a loop! Just another "I can't believe what people hired to solve problems do" situation. I've never seen such a thing, so that's why I got confused. Not my house and everything here is weird, so I'm proceeding w/more caution than I would usually. –  HostileFork Nov 21 '13 at 14:50
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@HostileFork There's usually a release hole or slot on the back of the switch which will release the grip on the wire allowing for removal without cutting. –  Madmanguruman Nov 21 '13 at 15:04
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The electrical "loop" from switch to switch is actually common when the black wire (on a white neutral wiring setup) is used to power several switches in a box (lights, fan).

It prevents connecting each one separately via a marette (pressure wire connector). Some will argue that it's a better way to connect them since there is no risk that any wire is badly seated in the marrete.

It's also much easier to replace switches individually this way.

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Switches are mechanisms to break (disconnect) or make (connect) the power line to the fixture. On a given circuit, all hot power lines are effectively connected.

Assuming standard connections, the lower wire is the power source, and the upper is the wire to the fixture. The loop connection allows the power wire to power the switch and its fixture, and also to forward the power to the next device, which could be a switch and fixture or an outlet.

There are alternative connection approaches, such as a pigtail (a short wire connecting the switch), the hot source line and the line to the next fixture, all connected by a wire nut. However a looped connection such as you have is also common.

Standard wire size for most US circuits is either 14 gauge or 12 gauge (heavier). It is important that no more than one wire be placed under a screw connection. A loop is considered one wire.

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unreasonable gauge of wire being used (that can barely fit in the screws without popping out),

The wire size looks normal, probably 14 gauge, maybe 12. That's what is used for lights.

the switch for the fan has two wires connected to the bottom. I realized that it's a single wire, stripped in the middle as a loop. But why the two connections? Does that actually accomplish anything to tie to (presumably) ground? If you know it's ground, why not just tie ground?

Stripping a wire like this saves time and is the best method to use when one wire is serving two destinations. The black wires are hot wires, not grounds. Most switches don't even have a ground terminal.

And the other wire goes into a hole at the top instead of the screw. What... is this about? The nice new white switches to match the new ceramic faceplate do not have the hole at the top; just the screws.

The hole in the top of the switch is an alternative to the screw at the top. You can connect to either one. The new switch is just made differently, i.e., without the hole.

You have to cut the wire to get it out, as far as I can tell.

You can remove the wire from the back of the switch by looking for the tiny slot near the wire's hole, inserting a flat-head screwdriver into it, and pressing down.

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