3 way switch and burnt mains

tke402

Hi All,
Ok I bought a fixer upper 5 months ago. I torn down some wood panelling on the walls and there was this wall sconce that was wired in a three way. I remember that there was one black wire attached to a white wire, the grounds are wrapped back under the clip and a black and a white that were connected to the sconce and no red.
Well in the scuffle of tearing down the walls the wire nuts came loose. I mistakenly wired the blacks to blacks and the whites to whites. Well I turned the power back on and the light worked. When I flipped on one of the switches the breaker tripped at the panel. I figured "no sweat" I made a mistake, since the breaker is tripped I'll deal with it later. Well, a couple of hours later I was smelling burnt plastic. I went to my panel to find that one of the main breakers was melting and the plastic that runs between the bus was also melted. I quickly killed the power at the meter. I changed out the mains and turned everything back on (after disconnecting all the wires to the wall sconce) and everything has been working for a couple of weeks now.

So I have a two part question. Am I in danger considering that some of the plastic on the bus is melted? Do I have to replace my whole panel?

My other question is how do I identify which white wire should be attached to the black wire at the wall sconce? I found several three way switch diagams but they don't seem to match my situation. Here is the break down of the current wiring:

Switch 1:
Red = Brass screw
Black = Capped
White = Black screw (common)
White = capped
Grounds wrapped back under the clip (metal box)

Switch 2:
Red = Brass
Black = Black Screw (Common)
Black = brass
2 Whites = capped
Grounds wrapped back under the clip (metal box)

Box:
2 whites
2 Blacks
Grounds wrapped back under the clip (metal box)
no reds

I remember a black attached to a white but I don't know which one. How can I figure it out?

Thanks,
TKE402

michaelpwalton1

Your description is confusing, because you are saying "3 way switch", yet you are telling me that in that box, there are two blacks and two whites and that at least two of the wires were spliced together (regardless of which ones) that only leaves two wires to connect to the switch. Therefore it would have to be a single pole switch.
Are you sure it was a three way switch? Was the light (load) controlled by more than one switch?
If in fact it was a single pole switch, then there are two pairs of 14-2 or 12-2 wires. One set would be the main feed (hot and neutral) while the other set would be the feed / switch leg to the light (load). Using a tester, check for power across one set of the black and white wire. One set should have power between the black and white while the other will not. Then read with the tester between the hot black to the box. You should get power. Then put that black on the switch. I would then splice the two whites together and remembering which black was left, connect it to the switch. If things don't work correctly, then reverse the black and white from the second pair (which would leave you with a black and white spliced together and a white wire left over for the switch).
If in fact it was a three way switch (at the start) then there could not have been two wires spliced, but instead one wire with a wire nut on it and not used.

tke402

Thanks for the reply.

The switches are definelty three way switches. There is a switch at the bottom of the stairs and a switch at the top of the stairs with a light in the middle. Before renovations I remember that either switch would turn the light on or off. Also i pulled off the switches from the wall to look at the wiring and they are the three way type switches.

TKE402

michaelpwalton1

Well, three way switches can be tough to work with and even harder when you can't see what is there (over the INTERNET). If your are sure it is a three way (and what you described sounds like a three way) then there must have also been a jumper coming from the two wires that were wire nutted together and it went to the switch.

If the box is grounded, you should be able to find out the combo pretty easy with any tester. If it is not grounded, then you'll need a tester that has a neon light or one that chirps. You will also need to go up and down the hall or stairs quite a few times.

Assuming that both existing switches worked the light correctly before you started and the box is grounded and you have not changed anything on / in the second switch, Now (in the open box)tag or identify each wire then read each wire to ground. You may find one or two of them have power on them. Remember which two they are, then go to the other switch and flip it. Now see which wires have power on them. If a different wire now has power, that one is a traveler and if one of the original wires no longer has power, then that one is the other traveler. Now install the two travelers to your switch. If it is a new 3 way switch, one screw will be a different color than the other two and may be marked common. Put the two travelers on the two screws that are not the common. Then wire nut the other two wires together and add a jumper from that splice to the common of the switch.

NateHanson

Nobody's worried about the melted main panel?

michaelpwalton1

I doubt that the melted plastic or problem at the mains is connected to or a result of anything going on at the three-way switch. Apparently there is additional work being done at the same time.

There is no doubt that the integrity of the panel has been compromised,, the question is how much and is the HO or person doing the work capable of changing out a panel or willing to make the financial investment?

If he can't get the three way working, maybe he should quit while he is ahead (no disrespect intended, we were all new guys at one time).

My guess (and it is only a guess) is that during working in the panel, the breaker was disturbed and became loose, which caused the over heating. Replacement would depend on the amount of damage the event caused.

elkangorito

I'm with you on this one Nate .

But I'm wondering if the OP is talking about the insulation on the busbars or not? If he is talking about the busbar insulation, I would strongly suggest that the panel, or at least the busbars within the panel, be replaced ASAP.

There are 2 reasons why busbars in such panels are insulated;

1] because the safe "air" voltage clearance is less than required (unless insulated).
2] Arc suppression in the event of a high current fault.

__________________
Switchboard design engineer & Licensed Electrician (Australia).

HouseHelper

I would make it your first priority to have the panel problem fixed. Melting plastic in a panel indicates high heat and arcing due to a loose or poor connection/contact point. If it is indeed the main breaker, then panel replacement is your only option.

The 3way switch problem is another matter. You description of switch 1 only has wires on two screws and should include another black wire. Please recheck this and post back.

Do you have test equipment and the basic skills to determine which wires are hot and to check continuity?