UVC Light Bulb Gets Smoking Hot Only in certain outlets.

Thread Starter

Lumenosity

Joined Mar 1, 2017
518
Hello,
I purchased a UVC Bulb today and after it was plugged in at home for about 20 minutes it got so hot it smoked and burned out.

It has a normal 100Watt light bulb screw in base (I think it's called E26??)

I went back to the store and got another.
They connected the 2nd one in for 15 minutes and it never got warm.

Took it home and screwed into two different lamps and it started getting very hot again in both.

Any idea what could be going on?

Thanks
 

Tonyr1084

Joined Sep 24, 2015
5,977
HMMMmmmm. Bulb works at store. Bulb fails at home. Well, just a guess here, but there's something wrong with your electrical wiring. Measure the voltage going to the lamp base. Or screw another bulb in that socket where the UV burned out.

Fully diagnose the problem before you start throwing money at it.
 

bertus

Joined Apr 5, 2008
21,364
Hello,

As @LesJones said, some kind of balast is likely needed for the UVC bulb, depending on the type of UVC bulb.
Perhaps in the store the testser had a balast installed.
Details on the bulb are needed.

Bertus
 

MisterBill2

Joined Jan 23, 2018
8,767
My observation has been that ALL mercury vapor UV light bulbs need an external ballast function of some kind. Usually that is a series light bulb. The reason is that once the mercury forms the conductive vapor there iis nothing to limit the current. So a series light bulb is the simplest cheapest ballast device, and it has been shown to work very well.
 

Tonyr1084

Joined Sep 24, 2015
5,977
I purchased a UVC Bulb today.
That's a lot to go on. Care to give us a make, model or photo of the bulb? You haven't even told us what voltage it runs on. Or what voltage you plugged it into. I have a pen. Why doesn't it make color ink? IDK! Maybe because it's black? Maybe it's because it out of ink? Please give us something to work from, otherwise we could be solving a problem that has nothing to do with your situation.
 

BobTPH

Joined Jun 5, 2013
3,316
All of which s true of any fluorescent bulb. And yet, we all use, or used to use, compact fluorescents that you can apply line voltage to.

I did a search earlier and found UVC bulbs that work from 120V directly. Don’t know if the one the TS used was one of those or not.

Bob
 

djsfantasi

Joined Apr 11, 2010
7,693
In the early days of non-incandescent light bulbs, bulbs mounted horizontally in a light fixture often burned out. Bulbs mounted vertically, base down, mounted in a lamp didn’t.

Off-topic story: When changing a bulb in a fixture, I placed the dead bulb on a carpet after removing it. The light came on! The forum decided that a static discharge was sufficient to fire the (CFL) bulb and an internal capacitor kept it on for a while.
 

MisterBill2

Joined Jan 23, 2018
8,767
The reason for my comment is that mercury vapor is both a heavy gas and a good conductor of heat and electricity. So if more of it is in the area between the conductors more current will flow.
 

jpanhalt

Joined Jan 18, 2008
11,088
The reason for my comment is that mercury vapor is both a heavy gas and a good conductor of heat and electricity. So if more of it is in the area between the conductors more current will flow.
I don't think the relative buoyancy of mercury vapor in air has much to do with it settling in a closed bulb under vacuum. I have used low-pressure mercury lamps of the type that produce mainly 254 nm UVC in both horizontal and vertical orientations for more than 50 years with never a problem.

Perhaps, we should wait for input and pictures from the TS.
 
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