# Why You Don't Do what You Don't Know



## frenchelectrica (Sep 26, 2003)

DaveTap said:


> Oh and the exploding light bulb... just BS but it sounds plausible right?... LOL :whistling



more than plauseble it is a fact i did see few indscent light bulbs do expoled when they get burn out that especally that true with old school 277 V bulbs at 300 watts and higher when the filment do break they will arc like crazy and build up pressure and kaboom.

I get that call few time when the old 277 tungesen filment bulb do go out kinda spook ya.[ there are some still around but kinda rare to see it but you will know there is a oddball or two still around here ]

Merci, Marc


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## DaveTap (Nov 8, 2006)

220/221 said:


> As far as the light bulb???? I don't see how that could have happened.... I have seen 240V thru a lighting circuit several times (lost N on MWBC)


When you lose neutral in a Multi Wire Branch Circuit the loads are in series with the other phase so it could only see 240V if the other phase has a direct short... if it has the same load the voltage won't change at all, and if the other phase has little or no connected load it would be an open circuit and the light would go out. :whistling

The other likely explosive possiblity here is there were already combustive fumes in the pit... most solvent fumes are heavier than air and would gravitate there. When he plugged in the light the spark ignited the fumes... 
(I still like my other BS explanation better!!!)


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## neolitic (Apr 20, 2006)

DaveTap said:


> When you lose neutral in a Multi Wire Branch Circuit the loads are in series with the other phase so it could only see 240V if the other phase has a direct short... if it has the same load the voltage won't change at all, and if the other phase has little or no connected load it would be an open circuit and the light would go out. :whistling
> 
> The other likely explosive possiblity here is there were already combustive fumes in the pit... most solvent fumes are heavier than air and would gravitate there. When he plugged in the light the spark ignited the fumes...
> (I still like my other BS explanation better!!!)


I don't know the physics of it but I do know that 30+ years later it still hurts to look at his face. This isn't one of those I knew guy, who knew a guy, whose aunt's boy friend's sister heard....


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## DaveTap (Nov 8, 2006)

gravtyklz said:


> Information Technology Contractor too huh? How is that going?


Actually its become almost a full time job... hardly doing anything else lately. Its kind of nice not having to work outside in the rain, snow, heat, cold, etc very often... unfortunately still spend some time in attics and crawl spaces.


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## DaveTap (Nov 8, 2006)

neolitic said:


> I don't know the physics of it but I do know that 30+ years later it still hurts to look at his face. This isn't one of those I knew guy, who knew a guy, whose aunt's boy friend's sister heard....


I'm hoping you (and everyone else here) learns these safety lessons:
#1 Whenever entering a sump pit, sewer, automotive pit, etc make sure it has been properly ventilated to prevent buildup of explosive fumes... especially if you are working with any combustible like gasoline or solvents!!!
#2 Do NOT use a lighbulb or lighting fixture to verify power is off!!! It can only confirm power is on. If the neutral were broken power would still be on but the bulb would not light. Always use an approved voltage tester... If you don't know what you're doing cheap outlet (or GFI) testers w/3 neons will catch most common problems... (but not overvoltage)
#3 Always treat any electrical device as if it is live... if it isn't now it could be at any moment!!!


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## neolitic (Apr 20, 2006)

DaveTap said:


> I'm hoping you (and everyone else here) learns these safety lessons:
> #1 Whenever entering a sump pit, sewer, automotive pit, etc make sure it has been properly ventilated to prevent buildup of explosive fumes... especially if you are working with any combustible like gasoline or solvents!!!
> #2 Do NOT use a lighbulb or lighting fixture to verify power is off!!! It can only confirm power is on. If the neutral were broken power would still be on but the bulb would not light. Always use an approved voltage tester... If you don't know what you're doing cheap outlet (or GFI) testers w/3 neons will catch most common problems... (but not overvoltage)


Exactly the point:thumbsup: Nothing I could ever forget. This was a mistake made by a very young person without proper adult supervision. It is alwys best to learn from _someone else's_ misfortune or ignorance.


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## jrclen (Jul 10, 2007)

shed-n-deck said:


> That makes sense.
> 
> 
> Just because I don't know everything, doesn't mean that I'm not capable. If I choose to learn about electricity, you can rest assured that I will succeed.


I shoulda put a smiley after my post. I was kidding. Sorry.


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## gravtyklz (Dec 24, 2005)

DaveTap said:


> Actually its become almost a full time job... hardly doing anything else lately. Its kind of nice not having to work outside in the rain, snow, heat, cold, etc very often... unfortunately still spend some time in attics and crawl spaces.


Our comany has been looking at doing something a little more specialized for money reasons. With the real estate market going down a little there seem to be more electricians low balling prices, and contractors who are willing to just call an electrican if you cant be there until a week later.

Sorry I know this is offbeat for the topic.


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## DaveTap (Nov 8, 2006)

gravtyklz said:


> Information Technology Contractor too huh? How is that going?


Actually its become almost my full time job...


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## shed-n-deck (Sep 25, 2007)

jrclen said:


> I shoulda put a smiley after my post. I was kidding. Sorry.


No problem.:thumbsup:


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## Sparky Joe (Apr 29, 2006)

With my company you can't go into a confined space such as a pit or a vault unless you are confined space trained and have a gas detector with you :thumbsup:


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## send_it_all (Apr 10, 2007)

Sparky Joe said:


> With my company you can't go into a confined space such as a pit or a vault unless you are confined space trained and have a gas detector with you :thumbsup:


That's isn't just your company policy, it's the law...Now we know why.


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## Sparky Joe (Apr 29, 2006)

send_it_all said:


> That's isn't just your company policy, it's the law...Now we know why.


Not quite the law, if it were I would've had confined space training and a sniffer given to me long ago.


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## neolitic (Apr 20, 2006)

Lot's changed since '73. We cut 1½" transite siding using a bandanna for a dust mask then too. Didn't know for years that transite was asbestos/cement.


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## Sparky Joe (Apr 29, 2006)

have you been checked for emphysema lately? 
Probably something I'd keep a close eye on.


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