I want to replace some light switches in my house with some of the x10 switches that dim and all that automation stuff. I know how to tell if a light fixture's power is off - the light goes out! Outlets are easy because I can plug a light in it. But what about the switch to the light? I have meter, but I am not sure what to put it on to test the power. Thank you for any help not getting me killed.
Switch the main off.
"I know how to tell if a light fixture's power is off - the light goes out!" You don't have the first clue about electricity. Please don't do anything. You are wrong wrong wrong. A light can be off and have full power. plenty of times the switch will be after the light. or an outlet could have a bad neutral but a good ground. SHOCKING!!! I'd suggest you find a buddy who does know something and is willing to help you. At the very least check everything with a meter. all wires to ground and across all wire combinations. even then, wear some rubber shoes. this isn't complicated but it can kill you. ...thehick
please read first before you begin : if there 2 wires in a switchbox, usually one is hot and the switch connects it to the other wire to send hot to the light where the bulb completes the circuit to the return wire. but the shock hazard can be from the switch hot to its own box which may be grounded providing a return path. or you could touch the hot with your left hand and the electricity passes up your arm and thru your heart when your right arm connects to a grounded radiator or water line or sink. your amp setting would measure the amperage passing across the off switch to the light and turn it on at the same time. switch on to read zero amps. switch off would read amps of the glowing light. if there are more than two wires in a box things may get confusing for you. hazard to you, the kids, whoever walks past the light switch until you finish your repair. in a bathroom where two switches are present the heater may be on a separate hot circuit. electricity is best repaired by two people, one with a cellphone and clipboard and tools, and you and your rubber gloves and a few battery lamps and flashlights. please read faq pages first:
Why would the light still be hot if when I turn off the breaker it goes out? I don't understand.
Hey Doug! You shouldn't do stuff like this if you don't know how to test for power.
Private joke
If you turn the light on at the switch, and then turn the breaker off, and the light goes out, then there is no electricity to the switch. This does not mean that there isn't still a hot wire inside that box. You obviously don't know enough about basic electricity. I suggest that you either do some reading or have a friend show you (preferably both). If you still insist on doing electrical work without the proper knowledge, then make sure you have enough insurance.
does the code even allow one outlet box to have 2 seperate breakers powering it?
for practical purposes as long as lite turns on ok, and then breaker turns it off, then box should be dead.
getting shocked isnt a good thing, but isnt the end usually.
always wear rubber soled shoes, stand on dry ground, only use one hand in box, to mimize across the chest shocks.
if in doubt trip the main house breaker!!!!
get a good book on wiring, and get a knowledgable friend to help, at least the first time.
It does not say you can't. Though I think you are supposed to tie the breaker handles together.
It is not uncommon have 2 or more circuits in a box with multiple switches. For example at an entrance where one switch is for a light in the garage and one switch on a different circuit for the kitchen light. Disposal/dischwasher is another box that may have 2 circuits.
I have seen a light box being used as a juction box for another ciucuit etc. It is especally fun when the neutrals from different circuits are tied together and you don't have the other circuit turned off and you go to disconnet the neutrals... BTDT...
FYI - I use a neon testlight, much easier than fumbling with a meter.
Kevin
Been there and done that. I had a lamp burn out when I was in the basement removing a fuse. It sure was an interesting shower of sparks.
It is also possible if there are two circuits in that box, you may turn one off, but not the other. Normally there would not be two circuits there, but don't count on it, it's your life.
Never bet that any wiring you did not do yourself is according to code. You are betting your life and I sure have seen many non-code installations.
I don't know what code allows, but at my front door, I have three switches. The two for lights inside and outside the door are on one breaker, and the three-way for the top of the stairs is on another breaker. I learned this the hard way.
What model of neon testlight do you use?
I have the made in China model..... Looks like the one in this article under the using testers section.
Kevin
Thanks. I already have those. I thought you were talking about the non-contact type that you just hold near a wire and it tell you if the wire is hot.
When I do this kind of repair I use multiple safety measures:
(1) turn off power. I verify it by attempting to switch the lights on. The probability of switching off the wrong breaker and the lights just burned out is small.
(2) I test for electricity with a meter. One probe on a known ground, and the other probe on the metal parts that I'm going to touch.
(3) I stand/squat on a plastic chair or other insulating material
(4) I avoid touching two different metal parts with two limbs at the same time. This has become almost an instinct.
(5) I use gloves or pliers with insulation
Often I get lazy and did not use all 5 measures above. Sometimes I test for (2) with my hand with a quick flick to the wire (of course I make sure I'm not standing in a tub of water), and sometimes I didn't turn off the power, but that was when I was younger and bolder.
I'm happy to report that in the past 20 years I have never been shocked or electrocuted. Before that, it's a different story.
Kevin Ricks wrote:
I use the GC inductive voltage detector. I started using it after encountering just the problem discussed here also often the neutral is switched instead of the hot or neutral and hot are reversed. Just a few of the "What in the F---!s" I've seen. =B7Two breakers serving the same circuit. Not tied together. Altho' I can't see how that would work since most breaker boxes I've seen have alternating legs next to each other. =B7Circuit tied directly to the main bus. That was a good one. With the mains off there were still lights on in the basement. Taking the panel off we found a circuit clamped directly on the incoming power feed! No one had a good explanation for that one. Imagine doing that quick short to see if the circuit is dead test on that one. (My dad used to do that) =B7Neutral tied to conduit ground. A clients kid got shocked pretty bad with that one. He did flip the garage switch in his bare feet in a rainstorm but still... =B7Ground used as neutral in a 3 way switch situation. =B7Soil stack used as neutral return. Guy was too lazy to run two wires. Made the toilet buzz on the second floor of a house I owned. Got louder when the lady upstairs used her toaster. =B7Neutral and hot tied together, when you flipped the switch, pow. The lady had been her own electrician! " I did it exactly like the book said" She was so POed that no amount of explaining could make her calm down. Fixed the problem and got out ASAP. BTW I often use a 1500W hair dryer to verify that a circuit will carry a rated load and to find breakers when I'm by myself. I did have a "gottcha" moment when the hair dryer I'd thrown out the 2nd floor window went off when I threw a breaker. Going back upstairs my non contact said the circuit was still live. Many scratches of the head later I went out side and the neighbor lady said "I turned off your hair dryer. It fell out of the 2nd floor bathroom window." As others have said here, even when you know what you're doing things can happen. Richard
ya it would be my luck the light would blow right when I check the switch thing is...It can happen, you're right
I have hooked into live wires, so long as you don't connect the two
i've seen electricians (not me)... change a fuse box to a breaker box without killing supply from power company
that's knowledge. I understand sometimes, the power company MUST kill the power as in my case having 60 amps? coming in (old sytle)
I have had 440 volts conduct through my entire body for around...maybe say...
4 seconds? it felt like 20 seconds, I think I would be deadbut saying, one one thousand, two one thousand, three one thousand, 4 on...
and the weight of my body finally freed both hands from the wire.
my ring burnt my finger, my neckclace burnt my neck
when I got up, I was very very confused and could not talk co-herently for about 20 mins.
I don't fornicate with electricity, I don't know jack about it, and I could learn if someone taught me. but that 440 may have very well saved me from my own hairbrained ideas.
the 440 was an old industrial line, a ladder had cut into that line, short story.. I had gotten onto the ladder...the line was supposed to be out of service BUT IT WON'T
LOL - Too funny. I especially liked the one about the soil stack.
"spudnuty" wrote in message news: snipped-for-privacy@o13g2000cwo.googlegroups.com...
Kevin Ricks wrote:
I use the GC inductive voltage detector. I started using it after encountering just the problem discussed here also often the neutral is switched instead of the hot or neutral and hot are reversed. Just a few of the "What in the F---!s" I've seen. ·Two breakers serving the same circuit. Not tied together. Altho' I can't see how that would work since most breaker boxes I've seen have alternating legs next to each other. ·Circuit tied directly to the main bus. That was a good one. With the mains off there were still lights on in the basement. Taking the panel off we found a circuit clamped directly on the incoming power feed! No one had a good explanation for that one. Imagine doing that quick short to see if the circuit is dead test on that one. (My dad used to do that) ·Neutral tied to conduit ground. A clients kid got shocked pretty bad with that one. He did flip the garage switch in his bare feet in a rainstorm but still... ·Ground used as neutral in a 3 way switch situation. ·Soil stack used as neutral return. Guy was too lazy to run two wires. Made the toilet buzz on the second floor of a house I owned. Got louder when the lady upstairs used her toaster. ·Neutral and hot tied together, when you flipped the switch, pow. The lady had been her own electrician! " I did it exactly like the book said" She was so POed that no amount of explaining could make her calm down. Fixed the problem and got out ASAP. BTW I often use a 1500W hair dryer to verify that a circuit will carry a rated load and to find breakers when I'm by myself. I did have a "gottcha" moment when the hair dryer I'd thrown out the 2nd floor window went off when I threw a breaker. Going back upstairs my non contact said the circuit was still live. Many scratches of the head later I went out side and the neighbor lady said "I turned off your hair dryer. It fell out of the 2nd floor bathroom window." As others have said here, even when you know what you're doing things can happen. Richard
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