Native wrote:
Hello,

Installing under cabinet lights and upgrading 30yr old switches and
receptacles in the kitchen when something I've never encountered
happen.

I have a neon-tester I use to make sure there is no power before doing
any work. I'm not sure if this is the official name for it, but it's a
very convenient tool I've had for a couple years now. For example, I
can hold one metal tip to a live black wire and put the other tip to
the neutral white wire and the light at the end of the tester lights
up. Or, if there is not a white neutral wire like a single-pole switch,
I can put the other metal tip on my finger and the light just barely
lights up.

Well, when about to replace a 30 old S.P. by my kitchen sink I went to
check to see if there was power running to the switch. I grabbed my
neon-test, put one metal tipped needle on the black wire screw and
tapped my finger on the other and the light lit up slightly for a brief
second before POP! and a puff of smoke.

After I made sure I still had my eye-brows I looked and part of the
screw is melted, the side of the switch is burnt black and my beloved
neon-testers metal tip is melted.

What happen?

Well, I theorized the screw was loose on the side of the switch and
think an arc was created and it was a one time deal.

Well, I was wrong, because in the next two days, all when working on
the same wall in the kitchen (two circuits), I've had three more loud
pops and a quick burst of light when trying to test.

I thought maybe my neon-tester had gone bad, but it even happen with a
new tester.

Any comments/suggestions? I do plan on calling a certified electrician
to come check everything out b/c in my three years of doing electrical
work around the house I've never had this happen. I do though want to
learn what is happening.

Thanks!


Lets see , you connected one end of a neon to a live wire and touched
your finger to the other wire.

I would have thought that makes you the ground wire and you would be
electrocuted .

but thats just me .

I have a multimeter but also bought a non-contact voltage tester . Its
a little pen like device that beeps if the plastic end is near a live
wire.

I did have a similar incident recently , where I was using a multimeter
to check for power at a switch , touched one probe to the screw and
poof , blew the breaker .

It seems it was an old switch with a grounded metal shell and I had
accidently caused the black wire to short to ground .