I changed the bulb though it was good still. I changed the switch. From the breaker box it goes; bathroom light, hall light, bedroom light, porch light. All other lights work just fine.
Lighting – How to figure out why the bedroom light won’t turn on
bedroomlighting
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If there are sparks, something has gone wrong and that breaker is doing its job and preventing your house from burning down.
Most likely the power runs into the box where that light is first, then to the switch. That's a completely normal thing. Look up the term "switch loop" for details.
First step is to remove that fixture and check for any water damage and damaged or loose wiring - both in the fixture itself and in the box it was mounted to. Since that's where the sparks are flying, it's almost certainly where the problem is. Before disconnecting any wiring, take lots of photos showing exactly where each wire comes from and goes to - you'll be grateful for those when you go to wire it back up.
Then it's just a matter of fixing whatever has gone wrong. Might just be a wire that has come loose and needs reconnecting. Or it might be severe damage to the wiring and require replacing. Won't know until you get in there.
If somehow that doesn't turn up any problems, do the same for the other fixture. Then the switch. Then anything else that is on the same breaker.
If the only paths in the circuit were those shown in your diagram, then your switch would turn off the light (but leave it in an unsafe condition where you could be shocked by touching the base of the bulb while changing it). Moving the switch to the hot side of the switch loop would make the wiring much safer.
BUT. This is not the only problem you have. The symptom you describe proves that there is another path from the light's neutral to the breaker-box's neutral. The principal danger to you, and to any future maintainer, is that you don't know where this path is. This means that you're remodeling your wiring without fully understanding it first.
I know it can be very difficult to analyze the wiring circuits in an old house.1 You have to open practically every j-box and even remove some wire nuts and separate the wires. You need to test voltage with the power on and check continuity with the power off, and get out of breath running back and forth to the breaker box.
You can't just give up and wire it the best way you can. You must trace everything until you know where it all goes, or in the case of the stuff you already ripped out, where it all went. You can't "ignore the other 3 that come into the ceiling box", because you don't know which of them should be left connected to each other and which should be capped off.
If you don't have the patience to trace all the old wiring, then you should hire a professional electrician to do it. Be aware, though, that this will be expensive -- unless you hire a guy who also doesn't have the patience to trace all the old wiring.
1. Believe me, I know. My house was built in 1891 and still contains some inaccessible knob-and-tube wiring that was originally installed for Edison direct current service.
Best Answer
First thing I would do is check the bulb on another verified working fixture. Sometimes even two bulbs are dead so you thought it wasn't the bulb. If not, then:
Next I would see if there was power coming to the wires that connect to the the light fixture.
But note that you need to test the wires going to the fixture, not just the fixture itself. You are ruling out the fixture as the cause of the problem.
If there is power going to the wires connecting to the fixture (with the correct light switch on), then you have found your problem - the light fixture itself.
Third, if power is not going to the wires that attach to the fixture, then you know at least that it is not the problem, or not the only problem (the fixture could also be bad, but you have another problem somewhere else as well if no power is coming to the wires).
If there is not power going to the wires connected to the light switch, but like you said the lights are wired in serial (one after the other), then since there IS power going to the bedroom light like you said, which you mentioned is the fixture before it, and the switch is wired in serial AFTER the bedroom light fixture, then your problem is the wire between the bedroom fixture and the light switch for the porch light; or, perhaps the wire is detached from the previous fixture.
That should be a good starting point. If there are only wires between the light switch and the fixture, and between the light switch and the previous fixture, then one of those wires is bad, if you have gotten to this point in troubleshooting.
If it is not in serial like you said but wired in parallel, then it is a little bit more complicated to find, but it should be pretty intuitive from here and this it a good starting point for you either way.
Update: I made a quick photoshop for you to help visualize. This is of course assuming it is wired in serial like you said in the same manner, but this is effectively how you will go about troubleshooting. Just change it a bit if it's wired differently, but this should answer your question fully.
I put a question mark with an arrow to the points of failure. It could be
Note 2:
You asked in a comment above how do you test if there is power going to the wires? Well the unsafe but easiest way is simply to attach a wire to the wire to the positive and to the negative and the just put the two wires to a working light bulb (side and bottom of the light bulb) to see if there is power going to it.
Here is a quick photoshop of this hack. Please use common sense and don't shock yourself. If you do this, screw each loose wire on top of the other wire, ON the light switch where it screws onto it. This will prevent the wire from flopping around. Be sure to put electrical tape on the loose end of the wire so they don't hit each other while you/re getting situated and blow the fuse or shock you while hanging.
If it lights up then the wires are fine and it's one of the things between the switch and the porch light. If it doesn't light up then the problem is either the wires or the connection to the previous fixture.
You can also test the voltage with a voltage meter but may not be necessary, although this is the better and safer way.