What could happened if I F*-ed up this wiring

If you had swapped the wires that went on the two brass terminals, it would still have worked, but you would have switched how the three-way logic worked (if the light used to go on when the two switches were one up and one down, and off when they matched, then it would now be on when they matched and off when one was up and one down). Of course you could recover from that by just putting the switch the other way round in the box (where it would end up with the two terminals on the right!).

If you had swapped either of the original brass-terminal wires with the dark-terminal one, you would end up with the stair lights only coming on for one position of that switch (depending on the position of the other switch), and never for the other position of that switch (regardless of the position of the other one).

Do you know how to draw and read diagrams of simple circuits like that? It's easy to learn. Then you can draw a few versions of the diagram as it would be if you swapped different connections around, and show yourself what the possible outcomes are, without making any sizzly noises.

I take it this is one of those 3-way switches with a subtle "hey I'm here" light inside it, that doesn't require a neutral wire run to the switch box. Those can end up being a little wacky as people replace their light fixtures from incandescent to much more efficient technology like CFL or LED. The reason is that the little "hey I'm here" light returns the (tiny) amount of power it uses through the light fixture it controls (as it must, having no connection to neutral of its own). With an incandescent light you'd never notice, because that tiny amount of power isn't near enough to make it light up. Replace it with an LED and it might end up flickering some, even when you have it "off".

 

Um, what I recall;
brown - ground
white - neutral
red - hot

 

If it's a three-way switch circuit (and if there are only three insulated wires coming into the box), that's not enough for one to be neutral; just one that either comes from the source or goes to the load, and two others that go to the other switch.

I'm pretty sure I would have painted or wrapped the white one to be some other color....

 

we only have a light at the bottom of the stairs, and only a switch at the top. i'm going to install a battery powered led light at the top, with remote control switches top and bottom.

 

You can get into some very interesting situations wiring up a three way switch and there are more than a couple of variations in homes.

Here are some typical situations with diagrams that may make sense in your situation. They include a number of situations and the accompanying wiring diagram

3 Way Switch Wiring Diagram (easy-do-it-yourself-home-improvements.com)

 

Tsk...Tsk.
It's the questions you DONT ask that'll get you hurt.

What @ChapmanF said.
Most times the breaker panel (or fuse box) keeps you from getting too far out over your skis.
There are illuminated switches that allegedly work with LED/CFL bulbs....
StackPath

 

Looking over this thread again, when I suggested in #2 "how to draw and read diagrams of simple circuits like that? It's easy to learn. Then you can draw a few versions of the diagram as it would be if you ..." I was thinking of diagrams in the schematic sense: the kind that are not going for artistic realism and making switches look like switches and cable look like cable and light fixtures look like fixtures all laid out in the actual shape of the house.

In schematic form, you just have symbols representing switches and lights and lines representing the wiring between them, laid out in the simplest way to make the circuit clear on the page.

So in post #7 with those nine different befuddling diagrams, those aren't the kind of "diagram" I was suggesting, but there's a good exercise there for the taking: a few minutes spent distilling those nine diagrams down to their underlying schematics would leave you feeling pretty confident you 'get' three-way switch circuits.

That can be true most times, but there's also a good argument in favor of just proceeding as if you're not really positive the breaker panel will save you. My parents once bought a 5-unit apartment building with the idea of retirement income. Among our later discoveries was that at some point in its history, somebody had bridged a circuit between two adjacent apartments. You could turn off the breaker in either apartment and it would still all be live. If any fault developed in that circuit either of those circuits, it wouldn't be cleared unless both breakers tripped.

There was also a notorious breaker brand that often didn't trip, in situations where tripping would be the desired outcome.

Also, conventional breakers aren't capable of detecting the kind of fault where something is arcing, being a possible source of ignition, but not drawing enough raw current to trip the breaker. Special arc-fault interrupting breakers can detect that, but only relatively new construction or retrofits will have those.

 

I made a quick sketch of two switches so you could see how they are wired. Move either switch from it's current position and the light comes on. If the light is on, moving either switch to the other position and the light goes off.

 

... because then the amps are able to march around through the light and still get home.

 

Ah but the volts become heat

 

Normal color coding is:

Bare, green, any combo of green are the grounding conductors (ground)

White, grey, various combinations are the grounded conductors. (Neutral)

Any other color is normally the ungrounded conductor (hot)

I have been in commercial wiring situations where there were literally a hundred wires in a bundle all slightly different.

Electrical Wiring Color Codes for AC & DC - NEC & IEC (electricaltechnology.org)

I am checking with the NEC book shortly. But you can repurpose a wire of certain sizes if properly labeled at each end. very limited use.

Replacing all the switches in my house. Why! I am bored to death.

Side note: IMO all residential wiring needs to be spot on and the correct colors used. It is not nice to find out someone used a white wire as the hot wire in a box. Or a fixture with no grounding conductor (safety issue). Saw a hot water heater with no grounding conductor in a new wiring project.
Everything in life needs to needs properly grounded.

 

lol

Here in Australia ..........

that is all i wanted to write

good luck

brown active
blue neutral
green earth

 

OK, almost finished with replacing all my switches and upgrade 5 to wifi.

This happened to me and may help the OP. Maybe!

On one of my 3way projects I thought I was careful to put all the wires back on the correct terminals. One set I redid had one switch that worked and the other that didn't. Rechecked my wiring and it looked like I did everything correctly except the two black wires on one 3way switch were not labeled. So I reversed those and it fixed the issue. Traveler and common were reversed.

 

Exactly! Be sure to hit the breaker to off and check all the wires in the box against the bare wire with a volt meter. You might get lucky.
It takes a very small amount of current to change you blood to pudding. Basically a 200 year old man.

Wear thick socks with athletic shoes. Don't stand in water and do not lick your fingers. Try your best not to have both hands in the box touching terminals at the same time. Or wear a thick rubber glove on one hand ( this is what I do when working on a live box).
You may live to come back and tell us your story!

 

Ok, we're getting a little far afield from Kris's original question, which probably only required working in a switch box on the wall, and she was (I hope) very sure to have gone to the service panel and shut off the breaker for that circuit.

Still definitely good advice to use a meter in that switch box and make sure no volts are coming in.

But if the topic is expanding to "working on a live box", there are a few more good ideas to throw in:

• If there is another way to do the job without working on a live box, do it that way.
• One hand in your pocket or behind you.
• Hang or stand the meter, don't hold it.
• Know where the box is in relation to the incoming power source, and double-check the CAT rating on your meter and the meter leads. Make sure the leads show no nicks/damage.
• Don't just measure the thing you expect to be depowered. Measure a known nonzero voltage first, then the thing you're checking, then the known voltage again. Make sure the meter worked both before and after checking the unknown thing.
• Wear personal protective equipment that won't just protect from electric shock but also from arc blast.
• If there is another way to do the job without working on a live box, do it that way.

 

I replaced a faulty switch on a 4-way hallway light recently, without turning off power to the circuit at the breaker box.

The reason? I didn't know which circuit breaker the circuit was on, and couldn't randomly turn the breakers off to find the circuit. I had 3 sons, in different rooms, all distance learning on their laptops on the home internet/Wi-Fi at the time.

So I unscrewed the two light bulbs in the light fixture, removed the wall plate over the switch, carefully pulled the switch away, and very carefully probed the wiring at the switch with a cheapo circuit tester (the kind that lights up when there's current, I was too lazy to get my Fluke multimeter out) by checking/bridging all the wires with the bare ground wires to see if any were live. None of the wires were live, so I noted what kind of switch it was (didn't know if it was a 3-way or 4-way initially), went to the big box hardware store and bought a new switch. Replaced the switch, replaced the bulbs and tested. All good... replaced the wall plate over the switch.

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Yup, been shocked by household current too many times. Most of them in my younger, dumber days.

I find I'm much more cautious in things (driving, power tools, ladders, etc.) now.

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