Trouble light troubles

[letterman]

Now I know why they call them trouble lights.

This dont make sense. I plugged in one of my trouble lights, and
immediately the bulb made a bright flash and burned out. I did not
think much of it, I figured it was just a common dying bulb. I
unplugged the cord and installed a brand new bulb. I plugged in the
cord and immediately that bulb flashed and burned out. After cussing
about the quality of light bulbs, I got yet another new bulb, and the
same thing happened. Immediate burnout.

At this point, I unplugged the cord and measured the voltage at the
outlet I was using. It measured 117V (normal). I plugged another
trouble light in that same outlet and it worked fine. Then I plugged
in several other power tools and stuff. All worked fine.

That's when I tossed this bad trouble light in the garbage.

However, I do not understand this. It's not getting 220V, so how/why
did the bulbs keep burning out? (just on that cord).

 

[RBM]

Now I know why they call them trouble lights.

This dont make sense. I plugged in one of my trouble lights, and
immediately the bulb made a bright flash and burned out. I did not
think much of it, I figured it was just a common dying bulb. I
unplugged the cord and installed a brand new bulb. I plugged in the
cord and immediately that bulb flashed and burned out. After cussing
about the quality of light bulbs, I got yet another new bulb, and the
same thing happened. Immediate burnout.

At this point, I unplugged the cord and measured the voltage at the
outlet I was using. It measured 117V (normal). I plugged another
trouble light in that same outlet and it worked fine. Then I plugged
in several other power tools and stuff. All worked fine.

That's when I tossed this bad trouble light in the garbage.

However, I do not understand this. It's not getting 220V, so how/why
did the bulbs keep burning out? (just on that cord).

The cord won't cause that to happen. I would check the voltage rating of the
three bulbs that flashed. If it's not problem bulbs, I'd put a meter on the
circuit and watch it for a while, as there could be an intermittent open
neutral, causing high voltage

 

[Jim Elbrecht]

-snip-

The cord won't cause that to happen. I would check the voltage rating of the
three bulbs that flashed. If it's not problem bulbs, I'd put a meter on the
circuit and watch it for a while, as there could be an intermittent open
neutral, causing high voltage

The cord can't have the neutral side go open? Like right where the
handle meets the cord? And where it stuck itself back together when
the light was taken down from the workplace to the bench to be tested?

If it tested fine on the bench I'd sacrifice another bulb on a fresh
circuit. If the bulb works I'd put the light/cord through a lot of
gyrations before I suspected the old circuit.

Jim

 

[Kevin Ricks]

Now I know why they call them trouble lights.

This dont make sense. I plugged in one of my trouble lights, and
immediately the bulb made a bright flash and burned out. I did not
think much of it, I figured it was just a common dying bulb. I
unplugged the cord and installed a brand new bulb. I plugged in the
cord and immediately that bulb flashed and burned out. After cussing
about the quality of light bulbs, I got yet another new bulb, and the
same thing happened. Immediate burnout.

At this point, I unplugged the cord and measured the voltage at the
outlet I was using. It measured 117V (normal). I plugged another
trouble light in that same outlet and it worked fine. Then I plugged
in several other power tools and stuff. All worked fine.

That's when I tossed this bad trouble light in the garbage.

However, I do not understand this. It's not getting 220V, so how/why
did the bulbs keep burning out? (just on that cord).

Possibly a bad connection in the cord near the bulb base can generate
enough heat to melt the solder seal on the end of the bulb and let air
into the bulb.
This has happened to me with regular light fixtures but as I remember it
took awhile in my case a day or 2.
Kevin

 

[dpb]

Jim Elbrecht wrote:
....

I don't, necessarily. I didn't even think about it. But I didn't
understand why RBM was having the OP test a circuit when Occam's razor
would point at the cord first.

Agree w/ the latter...

I'd hypothesize there's a fault in the socket base that is causing a
short when the bulb is inserted...

--

 

[Jim Elbrecht]

Can you explain why you believe an open neutral in the cord will burn
out a bulb?

I don't, necessarily. I didn't even think about it. But I didn't
understand why RBM was having the OP test a circuit when Occam's razor
would point at the cord first.

Jim

 

[dpb]

So, how will a "short" cause the BULB to immediately burn out?

I'd expect a short would more likely pop the breaker for that circuit,
or if it wasn't a "hard short" it might cause localized heating probably
accompanied by a bit of smoke/smell. And, as mentioned elsewhere on this
thread, a poor contact or partial short might heat the bulb base enough
to cause a "mechanical" bulb failure, but not "instantaneously".

I really can't think of anything which could go wrong with a trouble
lamp cord which would cause an "immediate" failure of a bulb as soon as
it's turned on.

I'd go with bad bulbs as the likely cause.

To check that, he OP might try taking a bulb from one of the other
"working" trouble lights he mentioned he had and trying it in that
bewitched unit.

Or one of the supposed "bad" bulbs and put it in the working trouble light.

My thought would be a high current across the base is blasting them, but
it's hypothetical. A poor vacuum seal on a batch would provide the
symptom as well, certainly.

--

 

[dpb]

I think the light is still in the trash. I was just going to buy a
new trouble light, but this needs further investigation since it's one
of those things that just makes no sense. Guess I'll inspect the
cord, plug, and open the head and see what's happening, if anything
can be seen. Then sacrifice another bulb which is known to work.

I'd do continuity checks on the cord, socket, etc., first as well as the
visual inspection.

Obviously if have another in the batch of bulbs that failed, try it in
another lamp/light first before the test of the problem one.

The only idea on the bulbs themselves I have would be a batch w/ an
imperfect vacuum seal unless they are a really cheap Chinese import
and/or mislabled.

--

 

[letterman]

-snip-


The cord can't have the neutral side go open? Like right where the
handle meets the cord? And where it stuck itself back together when
the light was taken down from the workplace to the bench to be tested?

If it tested fine on the bench I'd sacrifice another bulb on a fresh
circuit. If the bulb works I'd put the light/cord through a lot of
gyrations before I suspected the old circuit.

Jim

An open neutral on a plugged in trouble light means there will be NO
POWER to the bulb and nothing more. This is not an open neutral in a
220V line. If there was a SHORT in the cord or the socket, the GFIC
or breaker would trip. (this outdoor outlet is on a GFIC).

I have an extensive knowledge about electrical wiring, which is why I
cant understand this problem at all. It makes absolutely no sense.
The outlet is getting 117V. Neither the GFIC or the breaker tripped,
yet 3 bulbs burned out INSTANTLY and 2 of them were brand new bulbs.

Minutes later I used both another trouble light with standard bulb, a
power drill, a circular saw, and later on a florescent trouble light
too. No problems with any of that stuff.

Unless the whole thing was just a matter of coincidense (bad bulb in
light, and two defective brand new bulbs), there just seems to be no
explanation for this. The odds of coincidense for 3 bulbs all being
bad and burning out instantly is near impossible. They all died
INSTANTLY and with a BRIGHT FLASH. (Dead bulb)

I think the light is still in the trash. I was just going to buy a
new trouble light, but this needs further investigation since it's one
of those things that just makes no sense. Guess I'll inspect the
cord, plug, and open the head and see what's happening, if anything
can be seen. Then sacrifice another bulb which is known to work.

 

[Mark]

bulb filaments are actually fragile...you probably vibrated the bulbs
too much somwhere along the line.

Mark

 

[dpb]

Jeff Wisnia wrote:
....

I'll buy that vibration or mechanical shock to the bulbs are the most
probable cause of what the OP experienced.

....

Possible if dropped the whole bag or something similar happened in store
or whatever, but seems somewhat improbable there, too, if all new out of
sleeve...

If so, the individual trouble light would be immaterial. Don't recall
if OP said he had tested one of these in another fixture before popping
it into the subject cordset or not...

--

 

[Jerry - OHIO]

I have a trouble light that is used for automotive use ,with 12 volt
bulbs just like 110 bulbs.Wife got my spare bulbs and blew six of them
before she noticed they were the 12 volt ones. Now I keep my shop locked
..
Jerry




http://community.webtv.net/awoodbutcher/MyWoodWorkingPage

http://community.webtv.net/awoodbutcher/CARWRECK

 

[Doug Miller]

bulb filaments are actually fragile...you probably vibrated the bulbs
too much somwhere along the line.

And the explanation for multiple failures of new bulbs? Simple: he bought a
package that somebody dropped on the floor in the store, then put back on the
shelf.

 

[The Daring Dufas]

I'll buy that vibration or mechanical shock to the bulbs are the most
probable cause of what the OP experienced.

Many folks aren't aware that there are "Rough Service" light bulbs made
for applications like use in trouble lamps where an occasional bump or
short fall to the floor are not unexpected. AFAIK they have more
filament supports than regular bulbs, and correspondingly shorter
lengths of unsupported filaments.

http://tinyurl.com/6ahpbo

They're not cheap, but maybe if you're klutzy about dropping your
trouble lamp they could be a bargain in the long run. <G>

Jeff

I have one in my one "old fashioned" trouble lamp and it's stood the
test of time quite well.

Jeff

The rough service bulbs are often supplied with
garage door openers and many of them have a clear
or frosted silicone rubber coating to prevent
flying glass if the bulb is hit with a hard object
or a stream of water in a wash down situation that
could break the glass due to a sudden temperature
change. Friends of mine who served on ships said
that rough service bulbs were the only type they
used to light the ship. The bulbs are great to use
in a porch light mounted next to or above a door
for those who have a bad temper.

TDD

 

[The Daring Dufas]

I have a trouble light that is used for automotive use ,with 12 volt
bulbs just like 110 bulbs.Wife got my spare bulbs and blew six of them
before she noticed they were the 12 volt ones. Now I keep my shop locked
.
Jerry

I had a problem once where dingbats would
come into the repair shop at my workplace
and put regular disposable flashlight
batteries in my NiCad charger. Made quite
a mess.

TDD

 

[The Daring Dufas]

A little bit OT, but I wonder how many folks here know that they still
make and sell standard looking light bulbs with left hand threads?

http://www.sunshinelighting.com/item-12530-3218.htm

It's an anti-pilferage thing. They were used aplenty on subway cars back
when incandescent bulbs were the only practical lights abvailable.

I think the reason they are still being made is that the strings of
lights used around construction sites are easy targets for "bulb
snatchers" and using bulbs with left hand threads discourages that.
(Confirmation please?)

Jeff (Who wonders if anyone ever sold "thread reversing" light bulb
socket adaptors? <G>)

Back in the early 70's I worked for an electrical
supplier and we sold a lot of left handed bulbs and
pig tail sockets to construction companies. The thought
of some miscreant trying to steal the bulb is kind of
entertaining.

TDD

 

[Dave Martindale]

Possibly a bad connection in the cord near the bulb base can generate
enough heat to melt the solder seal on the end of the bulb and let air
into the bulb.
This has happened to me with regular light fixtures but as I remember it
took awhile in my case a day or 2.

The solder is just an electrical connection. The gas seal is made by
sealing a glass tube used to remove air from the bulb.

This isn't to say that a poor connection might not generate enough heat
to soften glass and lose the seal - but it would have to melt glass, not
just solder.

Dave

 

[Robert Barr]

The answer is simple: Somewhere along the line, this trouble light was
stored too close in proximity to a William Peter Blatty novel.

This being Halloween, it's clear your light is possessed.

 

[lp13-30]

FWIW, bulbs made for ceiling fans will stand up to the rough service a
drop light usually sees almost as well as the rough service bulbs made
for drop lights, at a fraction of the price. I finally started using
CFL's and find they last longer than rough service bulbs and don't put
out the heat. We have had people at work burn carpets by setting drop
ights down and forgetting about them, beside burning the crap out of
arms, but the main thing is that one drop of sweat on a hot incand. will
pop it immediately. One afternoon, me and a co-worker popped 4 or 5 in
about a 20 minute period that way. Larry