I have a ceiling light in the hallway with two light switches (dipoles?). The
ceiling light has 4 bulbs. The other day the hallway light wouldn't turn on
with known good bulbs.
Not knowing anything about electricity I *assumed* that one of the switches
had to be defective so I replaced both on/off switches -- that didn't solve
There's electricity in both boxes to other lamps so I know (think) that it's
not a circuit breaker problem.
Before proceeding any further (e.g. replace the lamp fixture), I bought a
simple current tester to see if there's any electricity in either of the
Not knowing what/how to test, I put the test probes on each of the wires for
both switches in every conceivable configuration. The diode never glowed.
Beside laying out a few hundred dollars for an electrician to deign making
his royal appearance, what can I do first to resolve this problem?
"Not knowing anything about electricity I *assumed* that one of the
had to be defective so I replaced both on/off switches -- that didn't
the problem. "
Are you an auto mechanic by trade? From your above decribed behavior,
I'd say so.
Have you checked to see if any of your breakers have tripped? Include
any GFCI's in the house as well. You never know how many stupid things
someone before you may have done so, putting an inside light fixture on
a circuit after a bathroom or garage GFCI is certainly possible.
I first checked all the breakers and GFCIs. They're fine. When I turn a
breaker on/off, it affects all the other lights in the box. Curiously, the
switches are on two different breakers. Before starting to replace the second
light switch, I was fortunate to accidentally flip another switch in the box
and to my shock, the light turned on. I found the other breaker and turned
How do I use the tester to verify that there's power coming into the light
switches? If it was a single switch, I wouldn't be asking such a lame question.
Did you look at the site referenced by Speedy Jim?
What you have is the three way switch configuration. Did you replace
the switched with the proper type (Three way)?
The four lamps are in parallel.
I'm looking at it now. I don't quite understand it yet. It'll take a bit of
time to sink in.
Yes, I bought identical replacements and when I replaced the wires, I swapped
them in the identical configuration.
Oh, when I took the lamp down I thought it was in series. One wire led to
the next like in an Xmas tree.
Let me ask the question just one last time: How do I use the tester to see
if there's any power reaching the switch to begin with?
On Sunday, March 5, 2006 12:51:27 PM UTC-5, John wrote:
If you look you will see TWO wires going from bulb to bulb to bulb. That's
You touch one end to a hot (black wire), and the other end to a neutral (white
Since switches normally just break the hot wire running to the light, you need
to find your neutral (white). You also need to be on the supply side of the
switch (the side coming from the breaker panel).
Stick the tester into the two vertical slots of a wall outlet to test its
That might be part of the problem too. That's what I do for a living,
and since I have a test environment that I can restore, I can make any
mistake without too much trouble. Remember that your house is the
It's more than curious. No one would install one light controlled by
two swtiches with each swtich on a different breaker.
Did this used to work? How did it work: could you turn the light
both on AND OFF from two different swtiches, no matter how the other
switch was set.? If that is the case, I don't see how two breakers
could be involved.
How many lights are "in the box"? How many switches?
So 3 different swtiches control this light? And 2 of them are in one
location? If they are in 3 locations, maybe you have a four way
switch. If I misunderstand, you probably don't.
You definitely have to read that website until you understand all of
it. If it is really confusing (I haven't checked) you might get a
book from the library, which might say the same thing in a different
Remove NOPSAM to email me. Please let
me know if you have posted also.
Two switches at either end of the hall turn the light on/off.
The power tester is working -- I plugged into a known live circuit and it glowed.
There's another 3 way switch in the same box which I used to see how the
power tester worked. To my surprise, it glowed when I turned the power to
the light off.
There are several other light switches in each box. All unrelated to the
hallway light. None of the other lights have any problems.
The hallway light was working fine up until the other day. There's no one
else in the house who might have touched something.
One switch confuses me: There are two (2) red wires on one side. This
doesn't match with anything in:
Another switch in the box have two (2) feeds, both black.
Good for you!!! And you learned a few things.
About the parallel lamps. What that means is that the black goes from
lamp to lamp and the white goes from lamp to lamp. If they were series
there would just one wire in and one out.
L L L L
Thank you times a billion Scott. I just finished wiring two new lines all
the way from one end of
my house, up through the attic, and down into my garage when the hall
lights went out on me
without any breaker in my box flipping off. I replaced the bulbs to no
avail. I then went to home
depot quickly to get new switches before testing if there was power to the
outlets because home
depot was about to close. When I got home, I tested the wires in every
possible way I could and I
couldn't get my volt meter to light up, so I changed the switches. Things
still didn't work. I really
wish I would have read this post, because I spent about 20 minutes up in
my attic trying to see if
maybe I knocked some wires loose while installing the new wires. Finally
I gave in, and searched
and found this thread, mentioning the GFCI's. Yep, the bathroom had a
GFCI that had
tripped......Next time I'll know where to start the diagnosis......once
again, thanks times a billion.
Yes, do be careful. It sounds like there is break in the circuit at
some point before power arrives at the switch. You say you tested
every possible configuration of wires and diode didn't light. Tester
itself is good, yes? Check on known good receptacle, hot(small slot)
to neutral or ground. Then with power on(wear gloves), check at each
screw terminal of switches to any ground- bare wire in box or box
itself if metal. If diode doesn't light, switches aren't getting power.
You will have to trace circuit to see how they are fed. If you are
lucky, you may see an obvious loose wire in one of these adjacent
boxes. But since you say some of these appear to be on a different
circuit, the break may be in a switch/ recep/ junction box in a nearby
location. Can you identify everything which is affected when when you
turn circuit off? The problem could be in one of these boxes.
Actually, I'm now wondering if you are right when you say things are on
different circuit- you mustn't rely totally on labels at panel- only
trust what you test. Hope this helps a little- do consider getting
someone more knowledgeable to help- even a pro- might not be as much
as you think
When I was 12, the Lionel train transformer didn't work. I tried more
than once to look at it/fix it. I didn't have any meters or special
tools. The last time I noticed that I'd taken the cover off and
fiddled with it without getting a shock. From that I deduced it was
the cord or plug, and it was the plug. This is no way to do things.
Even at 12, I should have been more careful.
Remove NOPSAM to email me. Please let
me know if you have posted also.
Is it storytime? My older bro was very mechanically inclined- still is-
half of the little I know I learned from him. As a kid, he fooled with
transformers, too. Told me of occasionally getting shocked. At age 5, I
was jealous of this gap in my experience, decided to close it by
carefully sticking something metal in outlet. Oh! so that's what he
was talking about.
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