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Light wont work after changing switch

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16K views 8 replies 5 participants last post by  nap 
#1 ·
I was just replacing several switches (a three set ) and a plug in a bathroom this evening. The three switches were connected to two separate fuses. I made a basic mistake and one of the switches wasn't disconnected and I got a bit of a shock. I then switched it off at the fuse box, changed that switch and a few others and turned them all back on at the fuse box. Two of the swithces work fine but the light connected to the switch from which I got the shock won't work.
I've checked the fuse box and it all seems OK. The same fuse that connects the switch that won't work also connects several other lights in other rooms which are working fine.
Any ideas. I've check the power using and electricity meter on the switch and got a signal once but haven't got anything since. If the fuse isn't at fault, what else could be causing this problem
 
#5 ·
I would not expect a bad ground to affect power to the switch. Neither would I expect a bad neutral to affect power to the switch. This could, however, affect your ability to measure voltage (if you use a volt meter to measure voltage relative to a failed neutral, you may not get a reading). A bad ground should not cause your light to cease working, but a bad neutral would, even if you have power to the switch.

If you are confident that you do not have power at the switch, then the problem is between the switch and panel. This could include bad wire, bad connections, bad fuses, etc. If you measure a voltage at the fuse, then you have eliminate a bad fuse, and the problem must be "downstream".

Do you have an idea of the wiring of this circuit? Could the switch be getting power from the panel through other devices, such as outlets, other switches, etc.? Are any other devices on that circuit not working?
 
#7 ·
How do you know bulbs are good? Did you replace them?

did you replace the switches with the correct type of switch (SPST for SPST)?

Do you have a voltage tester? If so, check from a ground or neutral to each terminal screw on the switches. Test with the switch in both positions. In one position, you should have power to only one screw and in the other, power at both terminal screws.

With the switch that is having problems, If you don't have any power at all to the switch, you made poor joints in the wire going to the switch. If you have power at only one screw regardless of the position of the switch, you have a bad switch. If you have power at both screws and still no light, you have either a bad lamp or some broken wire or bad connection from there to the fixture.
 
#8 ·
Thanks nap,

I’ve tried several bulbs so I don’t think that’s the problem. I also think the switch is the correct type.
I took your advice with the voltage meter and have power to one of the screws in one position and none of the screws in the other position. I’ve tried three different switches though so I’m not sure the switch is the problem either.

Any other ideas?
 
#9 ·
power to one of the screws in one position and none of the screws in the other position.
you are checking from a terminal screw to a known ground or neutral, yes?

I ask because if by chance you are checking from terminal screw to terminal screw, that is what you should get.

a SPST switch is almost always marked on and off. Which way are you getting what reading?
 
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