so I was switching out the 2 point toggle switch in the bathroom

Why? Was something broken or did you just want to change the colour? Pictures of the new and old switch would help so that we can determine if they are actually the same.

A description of the wires in the box and how things are hooked up would be helpful.

You may have mixed two circuits together when you randomly connected wires, so that's why everything is powered even with one breaker off.

You'll probably have to undo all of the connections, then turn one breaker on and test which wire is live. Then turn that breaker off and turn the other one on and see if a different wire is live. Then from there, we may be able to figure out how it should be hooked up.

Did you only mess with the wires in the switch box?

The old switch you had to jiggle the one toggle to get the light to stay on like there was a loose connection in it? And yes I only messed with the wires where I was swapping the light switch. And by everything being powered I mean the entire house. The one that is off is labeled as bedroom but there is power throughout the entire house.

And by everything being powered I mean the entire house. The one that is off is labeled as bedroom but there is power throughout the entire house.

What I'm saying is that wires from that bedroom circuit may have been in the switch box (but not connected to the bathroom circuit). When you randomly hooked things up, you might have connected those wires to the bathroom circuit. So now the bedroom circuit is being powered by the bathroom circuit instead of the breaker.

What cables are entering the switch box and how have you hooked them up?

I edited the main post. The two wrapped black wires are on the positive side. The other side has the white up top and the black beneath.

How can changing 4 wires cause a breaker to become completely null?

First of all, the black wires on your new switch are wrapped the wrong way around the screw. They should be clockwise so that as you tighten the screw, it pulls the wire into it instead of pushing it away. But that's just an aside.

So there are only the 4 wires? In the picture, is it hooked up the way it was with the old switch?

In the third picture, do you notice the metal tab between the two screws. That connects those two screws. Is that tab present in the old switch or has it been removed?

My first guess is the two old black wires come from the panel. You have one hooked to the hot side and one hooked to the neutral side. My second guess is that the new double switch has a tab between the two screws on each side that needs to be removed to separate the two circuits.

As to why they wanted separate breakers for the light and fan, I cannot answer that. It does not appear to feed anything else from that switch box, but that does not mean that behind the light and fan fixture there is not a feed to elsewhere in the house, which may be why there are separate breakers. At the breaker box, is there any decent labeling telling which is the fan and which is the light and if they feed anything else?

My guess is that the light was on the same circuit as the bedroom. It's probably the old wires.

At some point, a fan was added to the bathroom. It's probably on a new bathroom circuit (new wires).

This switch is probably set up as two switch loops from those two separate circuits and that tab is supposed to be removed. The old wires should be across from each other and the new wires should be across from each other. Not mismatched like they are now.

Having wires from two separate circuits in a box is fine. But I believe that since they are connected to the same device, that's probably a code violation and the two breakers should be tied together so that they both turn on/off at the same time.

But this is just my guess at this point. The best thing to do would be to do some tests like I said in my first post :

You'll probably have to undo all of the connections, then turn one breaker on and test which wire is live. Then turn that breaker off and turn the other one on and see if a different wire is live.

That would confirm if what I believe is true as described above is actually true. Just hooking things up and hoping it works is not the best strategy. Understanding what's going on is important.

And another minor issue, is there a ground wire in the box? It should be hooked up to the ground screw on the switch.

I imagine the new cable (with the black and white wires) should also have a bare ground wire.

Older switches did not have a ground screw, so that's probably why there wasn't one in the box, but all new ones are grounded. However, if there is a ground on one (or both) of the incoming cables you need to use wirenuts to make a ground pigtail and connect the cable(s) ground wire to the switch ground screw and to the metal box. If there is no ground wire in either cable, then as a minimum you need to ground the switch to the metal box.

Once you get it figured out, I also recommend wrapping black electrical tape around the switch so that it covers all the screws. It makes it easier to get the switch placed in the box at the right angle (sometimes boxes are not square) without any chance a screw will touch the metal sides.

Bruce

I recommend not wrapping electrical tape around it. It just makes a sticky mess for the next person who comes along.

If the box is so skewed that you have to angle the device so much that the screws would touch the side, then I'd suggest fixing the box. In fact, there probably isn't enough wiggle room to angle it that much.

But I know the electrical tape thing is a personal preference and lots of people argue for or against it. I've never heard of a pro doing it though.

made me feel better

:)

That's the only benefit, I think. It makes some people feel safer but it doesn't actually do anything.

On the plus side, while it is a sticky mess whenever I see it done it's like a warning that an amateur did this wiring, so be extra careful! :)

More because there is a lot going on in those boxes, didnt want any of the grounds touching anything it shouldnt (or being physically close with no barrier between) in any way possible. That and one of the boxes I redid from a previous person, my wife got shocked by one of the switches so I changed out the switches and wrapped them that way and havent had a problem. Whatever works.

I don't like wrapping devices with electrical tape either but to each his own. What I did want to say to Nick is to be very gentle with those old cloth covered wires, the insulation has a nasty habit of becoming brittle with age and breaking off. Years back I replaced a light fixture wired with that stuff and two days later had rewired half the house.