Arching

fast pasquale

So i was changing out some fixtures today and caused an arc (i believe im using the correct word), 2 times. I've changed hundreds of fixtures and it was actually a three way and i missed the other hot.. wire.. anyways.. to the point... When my screwdriver made the arc, the whole tip turned black and a piece of the metal chipped or looked like it got gouged. My question is why does the screwdriver get so damaged.. it would seem if my finger was up there it would have gotten burned or a chunk would be missing.. but when i touch the "wrong wires".. all I'll get is a little 110 shock.. that is only uncomfortable at the worst.. why does this happen?? Thanks.. I know this is an amature ?.

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Chris Frate
Pasquale Floors

mdshunk

Put your screwdrivers away and step away from the fixture.

A guy who burns up his own tools changing a fixture doesn't have a prayer of installing the fixture properly. Leave that to the qualified people.

fast pasquale

I've owned rental propery for 6 years and have changed hundreds of outlets, fixtures, switches etc.. I'm not asking if you approve of my techniques.... This is the first time I've arched anything in years... I'm asking why this happens so i can understand.

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Chris Frate
Pasquale Floors

Speedy Petey

The reason you get what you call a "little" 110v shock is because you are not fully grounded whe it happens.

The reaons your drive got so damaged is because it WAS fully grounded, and is metal! Think arc welder.

BTW- I agree with Marc. I don't care how many fixtures you've changed. You should not be messing with this stuff.

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boman47k

Why did this happen? Might want to kill the circuit you are working on...at the panel . I was raised with rental properties and have also done some electrical. I don't believe I have ever blown a screwdriver up. Well, maybe a gap out of a pair of cutters a long time ago. Really,Pasq, I learned the hard way to go to the panel and de-energize! And I prefer to do the de-energizing myself and double check with meter. If you ever get hit just right with 110, it can be a little more than uncomfortable.

fast pasquale

hmmm.. really? not even switches and fixtures??.......maybe i will retract some of my hostility toward md... As a property owner.. i can't call an electrician everytime i need an outlet switched out.. i'd go broke. Are you saying that I'm just lucky that no serious injury has occured to me yet??.. Could you get serioulsy hurt doing these kind of jobs??.. I know the answer is yes.. but i guess im looking for more explanations..
I would tell h/o's this reguarding sanding/refinishing their floors so I get where you are coming from.
Thanks so much!

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Chris Frate
Pasquale Floors

fast pasquale

much appreciatd boman.. but it's a multi family unit and sometimes turning off the power isn't an option

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Chris Frate
Pasquale Floors

K2

My answer to the original question would be that there are more free electrons in a screwdriver than in your hand. So more free electrons can move faster and faster causing a pile up on the electron highway, wrecking your screwdriver.

mdshunk

Pasquale? Are you married? If so, please PM me with your address so that I'll know where to send flowers at some point in the future.

fast pasquale

md.. i'll email you with my address.. Just send the cash.. The fiancee is picky when it comes to flowers.

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Chris Frate
Pasquale Floors

A.W.Davis

md his address is 2898 Carob street Antioch Ca and send the money asap....I am slow on work errrrrrrrr I mean Pasquales fiancee wants some new shoes

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A.W. Davis Construction Co.
http://www.awdavisconstruction.com/
Your friendly remodeling contractor

boman47k

For no longer than it takes to make a change, I'd make it one. I'm too careless not too .

K2? I'm not even going to paste what you posted . But it seems like someone once told me many years ago about using the back of their hand to see if something was live. That way your muscles would not contract and grab the wire. "Yeah, I'll make a note of that!"

Maybe I misunderstood what he was saying. Reminds me of the time I had changed a timing belt and needed #1 piston up. Told my son tp put his thumb on #1 cylinder while I turned the starter. As I was telling him this, he was placing his thumb on #1. When I told him to let me know when it blew his thumb off, lol, he jumped plum back away from the vehicle with a terrified look and said, "BLOW MY THUMB OFF?!!! I still crack up when I remember that.

Mike.GCOC

The answer to the original question is simple: human bodies have resistance and a metal screwdriver does not. That's why when you get "zapped" from a hot wire it doesn't trip the breaker. A metal screwdriver is a pure conductor with no resistor so it's an automatic short. The arc'ing comes from being close enough to ground to cause the electrons to "jump" and trip the breaker. In my younger days I used to use the "poor man's method" of finding the circuit breaker by simply quickly grounding out the hot wire with minimal arc'ing causing the trip (not recommending this).

Sparky Joe

Without reading if I'm repeating the other posts;

An electrical arc is around 35,000 degrees or 5 times hotter than the sun, the steel of your screwdriver melts around 2,000 degrees so that's why you see a chunk missing from it and all the 'black' is carbon tracing of the arc breaking it's way through, or just the carbon left behind from the burning.

Your skin when dry has around 2000 ohms of resistance which would tell you how many amps is going through you at 120 volts, not many at all compared to a steel screwdriver at around 1 ohm.

A static shock, though low current is around 1000 volts if you can feel it.

Magnettica

Doesn't this also have somewhat to do with the trip curve of the circuit breaker?

mdshunk

Pasquale, an electrical industry hero suggests that I post the link to a book from the Centers for Disease Control for you. It's a great link, too.

http://www.cdc.gov/niosh/pdfs/02-123.pdf

Sparky Joe

A breaker will not trip with a person completeing the circuit.
.06 amps is hardly enough to trip a 20 amp breaker, water also poses too much resistance to trip a breaker, although a considerable amunt of voltage will be felt by the idiot completing the circuit.

The trip time you speak of an inverse time thermal magnetic trip breaker only reacts to currents above the rated breaker limit.
If it's a short circuit, the magnetic portion does it part trip out quickly(within 5 cycles), for an overload situation the thermal portion does the work, and at an overcurrent of 21 amps it may half an hour for the breaker to trip.

JamesNLA

Your statment is true, but not because of why you say. Closed circuit, is a closed circuit. Whether it's hot to neutral or neutral to hot makes no difference. True that a breaker will not trip if you happen to be using your body as a conductor. You'll be dead after just a few amps.

boman47k

Dang, all this time i thought breakers were supposed to trip if a person made up the circuit. Now it seems their main purpose is tp maybe protect whatever they are servicing and preventing fire? I also thought if you grapped one lead in one hand and the other in another hand, the charge would pass through your heart and kill you. Heheh, guess the trick is to grap the neutral first. I think I have a better way. I won't be grapping either! Whew! I have been told of an uncle that would stop an engine by placing his hand or fingers on the distributor or plug wires somehow. Maybe wires without boots.
This turned into an interesting post.

fast pasquale

First off... Thanks for all the replies. 2nd.. md...I really appreciate that link.. I will read it.. eventually. I guess it's pretty obvious that i need to read it .
What happened today and what you've all said has really got me thinking that i need to take better precautions when working.... and learn more basics.. I started reading a basic wiring book that i had in my arsenal. Before i kill myself..
James .. can you expand on the part where i could die . Am i in any grave danger when it comes to working on outlets and switches. Once again.. thanks to all.

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Chris Frate
Pasquale Floors