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Joined: Jul 2004
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My sunglasses are ANSI/OSHA safety glasses and I wear them all the time. If I am not worried about flying stuff, I am worried about U/V frying my eyes.


Greg Fretwell
Arc Flash PPE Clothing, LOTO & Insulated Tools
Joined: Jul 2002
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Some very good comments here, thanks for starting the thread Sparky.
To be fair, I've only ever had two incidents that stand out in the whole time I've been working in the electrical trade here.
The first being during my training as an industrial electrician, myself and one of the site electricians were replacing a motor control cabinet on one of the large conveyer belt drives, this was done live to keep the rest of the plant going at the time.
We coned off the area, this was way back before PPE and AF suits, you just wore safety glasses and fire retardant overalls.
The other guy Pete, went to use a Crescent and dropped the thing and it fell across the 3 2000A bus-bars feeding 5 of these motor control cabinets, the explosion was awful until it cleared.
His overalls caught fire and I pulled him out of the area, I sustained minor burns to my legs, after that incident, all un-insulated tools got banned from the Electrical Department. grin

The worst electric shock I have had to this day happened about 20 years ago and it was in a house, just down the road from here.
I was sent to this place to install an extractor fan in this ladies bathroom on a Friday afternoon.
The lady said she wanted it to come on with the light in the bathroom and it needed to have a 3 minute run-on time.
So I pulled the fuse for the circuit which took out most of the lights in the house and set the fuse carrier up on the meter.
I then got up in the roof and cut the lighting feed cable and proceeded to make up a junction box for the fan feed, as I went to strip back the phase and neutral conductors of the feed cable to make the terminations, I had 230V between my left and right hands, I could not let go of the wires as the roof was quite low where I was working.
That 50Hz buzzing in my head is something I will never ever forget and I could feel my eyes closing, I moved to the right and fell through the ceiling to break contact with the wires which clashed as I fell and blew the pole fuse out at the road.
Upon investigation, the lady said she put the fuse back in because she couldn't read her newspaper and then began berating me for the hole in her ceiling and the fibreglass batts that were now in her bath.
I finished the job and fixed the ceiling, but I was not the "full quid" for a few days after that shock though.

Joined: Jul 2002
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Steve,
I have to agree with what you're saying though, there should be, as part of an apprentices training, a course that shows what arc flash will do and to see that first hand and of course how to avoid this happening in the first place.
I remember doing a similar thing with Eaton Controls? with HV protection, years ago and I've never forgotten what they taught us, I mean it took two days, but over my career, it was time well spent.

It's almost like when we burn a derelict house down over here, one room at a time and get the new kids in there and teach them about flash-over and fire science/behaviour, it's in a training environment, so they aren't put at any real risk of injury.


Joined: Oct 2000
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sparky Offline OP
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We're in a dangerous trade Trumpy , i tell a lot of noobs that one is literally working on a bomb when they work it live , they probably just think i'm a crazy old man

And truthfully, they might be right.......but at least i'm still around!

A safe '18 to all my spark chums!!

~S~

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I imagine 50hz has a little different buzz than 60hz. It is more of a ring at 400 hz. wink


Greg Fretwell
Joined: Aug 2008
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Luckily I have not encountered any severe arc faults, though I have done unsafe work situations in the past that I now would not repeat. In my apprenticeship, short circuits at a standard outlet were demonstrated (230V 16A with a few hundred amps short circuit current) that was the most I saw live.

The funny thing is that all the 6 or 7 shocks I ever got were at home, none at work.
The by far most stupid was when, at age 20 or so, I thought I was good enough to change a broken 230V outlet live. Of course it happened that I got shocked, from left hand to right hand, and tripped the 30mA GFCI (with of course more than 30mA going through my heart until the GFCI mechanics acted; just fyi: GFCIs are in the panel in Europe, not in the outlet).
As someone above wrote, the 50Hz vibration in your muscles is a feeling you never forget.

The most odd was that I tripped a 230V GFCI with my nose as a teenager. It hurt. In Germany, the ground contacts of an outlet can be touched when no plug is inserted. My parents had a burning smell in the house (which later clarified to be from outside) and asked me to see what was going on. The store room where it smelt had one never used outlet in the corner and upon my close smell test on that, my nose touched the ground pin that was unknown miswired to 230V hot.

Btw, here in Germany, nowadays you get tought that a 120/230V or above shock ALWAYS requires seeing a doctor and getting an ECG. Compare that to the old electritians handbook that tells you how to find live wires by touching!
How is that in your countries? Every domestic voltage shock sent to the doctor?


And here's a bit related wake up call that tought me for my work as a machinery control-cabinet engineer: Sometimes, if pneumatics are required on a machine, they are put in a sheet metal cabinet like the controls. In the situation at a large company I worked at, they had an electric control cabinet about the size of a room door, and a flanged-on cabinet same size with pneumatic valves and hoses in it. The area where the two cabinets met was cut through for wiring. Somehow, at night the 20 bar (300 psi) feed hose broke off from the main stopcock in the pneumatics cabinet and started flying around in the whole cabinet. Destroying the electric gear like a hammer, getting 230V on the 24V side and everything electric in the control cabinet went up in flames, fed by the air rushing in. Some people were working night shift and cut off the power, I don't remember if the cabinets door was knocked open from the hose though. That tought me to use separate cabinets and stable separators, when pneumatics are involved.

Last edited by andey; 01/10/18 09:27 AM.
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sparky Offline OP
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Quote
Btw, here in Germany, nowadays you get tought that a 120/230V or above shock ALWAYS requires seeing a doctor and getting an ECG. Compare that to the old electritians handbook that tells you how to find live wires by touching!
How is that in your countries? Every domestic voltage shock sent to the doctor?


I was apprenticed to a few of those old timers Andey. They called it 'backhanding', in that they'd use the back of their hand to 'test' a wire ,knowing that the reaction of muscles contracting would pull their arm back to them.

And a ECG would be interesting , really never thought of that the entire three decades i was qualified to run one. For the most part i think burns , or entrance/exit woulds are the focus.....

~S~

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sparky Offline OP
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Originally Posted by Trumpy


It's almost like when we burn a derelict house down over here, one room at a time and get the new kids in there and teach them about flash-over and fire science/behaviour, it's in a training environment, so they aren't put at any real risk of injury.



I can recall being a 'noob BBQ' crew participant , blinded by smoke etc , with a training officer screaming "are you !%$#@ jokers all i get for my tax dollars?"


He definitely left an impression....

~S~



Joined: Apr 2002
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~s~
I remember from way back one of the senior guys used two fingers as a tester.

Me, I had a ‘Wiggy”; matter of fact I still have that one in a cabinet.



John
Joined: Oct 2000
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I don't know if it was the biggest wake up call, but it ranks right up there with me.

Back in the day a local Pizza place was enlarging a bathroom to make it accessible for the handicapped and the Panel had to be moved a couple feet to be outside the room.

The SE conductors had to be taken out, conduit extended a few feet, and longer ones pulled in.

Outside, I had the meter pulled and was loosening the lugs to get the wires out. The Neutral lug also had a solid bare copper wire in it that went to a Bonding bushing on the EMT connector below.

Right now I can't exactly picture how it happened, but there must have been a lot of tension on that bare copper because when things were loosened it somehow whipped into a live terminal and sprayed what felt like hot sand into my face. Luckily, I had closed my eyes before it hit.

I was lucky that day for sure.

Bill


Bill
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