Breaker trips

I have two switches in one plate. When the first set of lights are already switched on through one switch, and then I switch on another set of lights with the second switch, the circuit breaker trips and the first set of lights go out. What should I do?

 

What's changed? Has anybody changed anything electrical, altered any wiring, replaced any switch or receptacle, bought any new appliance, or even changed a light bulb for one of a different wattage?

 

In addition to what John has asked, I am curious. Does the second set of lights go out as well when the breaker trips or do they stay on? If they stay on, do you hear any kind of noise like a loud pop when you turn on the second switch?

I am thinking that you have two separate circuits here that feed these lights and that when you turn on that second switch you are causing a direct short between phases.

Is this a new house to you or someone else, if not, then as asked earlier what has changed???

 

Thank you for your responses. We just moved into the house 3 months ago, and both sets of lights were working fine then. The only thing that has changed is that we painted the walls in the room so we took out the faceplates and covered the switches with tape. When we took out the tape last weekend, and tried to turn on the lights that's when we realized there was a problem. I don't think that we touched any of the wirings as we were taping and putting back the tape. Also, since it took us 2 months to paint the wall (don't ask!) and we had not switched on the second set of lights for a long time now, I don't know how long ago this problem started or occurred.

To answer the other question, when the first set of lights are already switched on, and we try to switch on the second set of lights, these three things happen (or not happen) concurrently: the first set of lights go out, the second set of lights never go on, and the circuit breaker trips.

I just bought an electrical tester. Would using that help me diagnose the problem?

 

You probably disturbed the wiring indirectly by disturbing the switches and receptacles. Shut off the breaker and pull out each receptacle, light fixture and switch on the circuit. Inspect the wiring, tighten connections, and repack carefully, making certain that the ground wire doesn't contact any parts of the receptacle, switch, or light fixture. Make sure no exposed copper protrudes from any wire nut. If your receptacles and switches are wired with those push-in connections, this would be a good time to move those connections to the adjacent screws. Might just work.

 

I suggest using a simple test lamp. If you have a 2-wire lamp extension cord, plug a lamp into the cord cap and snip off the cord plug so that you can connect the cord leads to the wires you are testing.-----Remove the lamps from the 2 fixtures that are controlled from the 2 wall switches-this "opens" the circuit. Remove the switch (switch #2) that is causing the breaker to trip and "wire-nut" the cord test leads to the 2 wires that switch #2 was connected to.The test lamp should not light. If you insert a 60 watt lamp in the fixture controlled by switch # 1 and have a 60 watt lamp in the test-socket,then touch the cord test-leads across the 2 terminals of switch #1 with switch# 1 in the "Off" position. Both lamps should be dim because they are in series across 120 volts with 60 volts across each lamp- "OK" circuit..Use lamps of equal wattage in the fixtures and the test-lamp socket. A dim test lamp in series with a dim lamp in fixture #2 indicates a normal circuit.---Good Luck!!