Question

[rick]

How many times does a grown man have to elecrocute himself before he learns to always check he has turned the power and pull the plug out of the socket before he goes messing around inside audio stuff...?

Damn sony amp i was just fixing has a power off button on the front that just turns power off to the relay switch on circuit board not the transformers and power supply
and it has a fixed power cord
( not a detachable iec lead )
so if it is on at the wall .. well its on all through the box except for a couple of front panel lights

power kills folks , and tonight it just F@#$ing hurt until the circuit breaker flipped .. which is 1/2 a sec too long ! .

you would think at my age and stage of life i wouldnt ever add another zapp to my list

you would think ..

It was geting late and i was getting lazy and stupid

add this to the list of dumb things i have done so you dont have to !

[Hybrid88]

Good advice. I did an electrotech course at TAFE a couple years back and it was a very interesting insight into what can happen. Apparently your resistance to shocks also diminishes the more you've had shocks in the past, so it doesn't get any less painful.

One thing I will add is to still be careful even when it is off and unplugged. Apparently the cases of techs being killed from fixing microwaves is scarily common. The super heavy duty capacitors can deliver enough shock to kill in one of those without proper discharging.

That said, we all get lazy, we all leave stuff on when we shouldn't. But to repeat what one of my teachers said, electricity doesn't give second chances. Never let yourself become complacent, cause it may be the last mistake you ever make.

[Gian]

I've done the same thing, Rick. Safety switch needs to cut in just a fraction sooner.

Now if it has an attached plug I hold the plug even though I only have one hand to stick inside the amp. Or I will double and triple check I have powered off the amp - or pulled the IEC lead.

If I am getting tired I will stop and come back after I am rested. An amp debugging is not worth my life.

[Drumstruck]

I learned when a young bloke not to touch the glowing valves - it was like someone doing a drum roll on my with hammers. Same story with sparkplugs when the bike or car are running..... and with welding - don't let yourself be the earth - every time the welding rod left the metal the aftershock ran through me into the ground (wet grass and bare feet - on the farm). 3 lessons are enough.

[Milo]

I wonder if Mr Clever DJ is still on this planet: he was setting up his PA in a pub, proudly built it himself despite not having a clue, he says, of what he was doing......standing there with a jack plug in his hand, which was his home-made 240 volt mains connector.

We backed away very quickly.

[Alastair Reynolds]

And heres a good example of what a lot of volts will do.
A curious Rat and his friend decided to check out the Combiner feed from our AM transmitter with 2 x 5KW AM transmitters running through it .
Given the Base impedance of the tower is quite high and inductive the voltage at that point is about 27,000 volts at around 1MHz.. RF burns deeply so at least it would have been quick

[Wiz]

I have done this quite a few times. The 240V dance.

Everytime without exception has been when I have been tired and in a rush.

The last one was a godamn front loading washing machine, trying to secure the tub, about 2am with the removalists turning up at 6am. Been packing all day.

For me, its the "jarring" senstion, almost like being hit by a van (thats happened too) crossed with an explosion inside.

Followed by that blank feeling, completely disoriented. Luckily for me, its always been the back of my hand, arm never actually grabbing hold of something, which is probably the only reason I am still here.

Stay safe Rick, you have a couple of real good reasons to make sure you are around for a long time.

Actually, good message for everyone who is working on gear, to slow down, double check power, and perhaps leave that thing till tomorrow when you are fresh


Wiz

[ether]

As a young tacker I was talking to my mum in the kitchen and decided to put both my hands into the slots of our $5 Big W toaster (which wasn't hot at the time - I'm not THAT stupid).

I was only saved from a Darwin award-winning premature death by three things: my 240V-powered frightened reaction that yanked the toaster from the mains (and hurled it across the room), our horrid green lino on the kitchen floor, and the humble aussie thong.

[rick]

Yes well it's dumb , that is for sure
My pinky is still spasming this morning
And the back of my elbow

Just stick "oh Rick was careless the other day
In the back of your mind .. "
I have done the 2012 Zappo Quota for all of us ..
So you can enjoy the silly season
And those Chinese Christmas lights in safety !

[rob]

ah, the RF burns, Alastair. I've had one and it took weeks to heal, they are a different sort of electric shock altogether.

I also got a dose of 240V this week after reaching across the back panel of a rack of Neves. The tech who built this didn't put a boot or sleeving on the pins of the IEC socket and I layed my arm across it.

The thing to be wary of about getting a shock from inside a piece of equipment is that the safety switch won't always kick in in this situation as the current flow may not be to ground but rather across your arm etc.

[wez]

I got bitten by an old Leslie amp a while back... I was telling Dave McCluney about it (hey Dave), and he offered me this sage advice -

"When you're working on something dangerous, always make sure that there's someone else around... to call the ambulance".

Wise words.

[Sammas]

This thread scares me!

[rick]

hey rob
some how your story doesnt make me feel any better


be safe out there is my thought
if you can't be safe be careful
if you cant be careful
dont ..

[obutcher]

I leant pretty early as a kid. My Pop was building me a train set and told me very sternly NOT to unlock the door and try and switch it on as he would be finishing it on the weekend. After he didn't come that weekend I found the key, thought I'd unlock the door and try and turn it on in the dark. Turns out he hadn't finished with the wall socket yet and didn't put it back on the wall properly. My small fingers touched the wires on the back of it.

One scared and upset child self later I knew why I was warned!

I think it's why I now need to learn more about electronics now, the association for me has always been one of pain until recently so I didn't explore it.

[davek]

1) use a isolation transformer
2) use a ELCB
3) never assume it's safe until you've checked twice (y'lknow, like Santa and his list...)

[Gian]

ELCB?

[Wiz]

ELCB?

earth leakage circuit breaker

[Drumstruck]

Electricity is invisible - assume it is there until you know it is not

[zenelectro]

This thread scares me!

I worry more about users safety as opposed to the rare occurrence I get a shock.

Some of the gear I've had across the bench has been potentially dangerous and fortunate there was a non safety
related fault. I've stopped counting valve guitar amps that had either no safety earth or one that was physically
loose / NW at all.

IEC mains leads - it's a good idea to check them. If they are used regularly the safety earth can get pretty loose.

Differentiation between safety earth and audio ground. A lot of stuff gets safety earth lifted to try and solve a
noise issue. This is more common in hi-end than pro. There is a lot of DIY gear creeping in to both markets
which can have a safety impact.

High power single ended tube amps warrant a fair bit of respect with anything up to 2000V on the OP tube HT.
Had one in a while back with no bleed resistors on the caps = 1100V floating around in there for weeks. That was
someone's DIY effort.

cheers

T

[heathen]

Mmmm one of my very first lessons in life and about the furthest back I can remember was pulling out the bulb from a bedside lamp and sticking my finger in. Still don't think I've told my parents about it.

Sort of like sticking my finger in the cockies cage at Skippy park when about 3yo, less than a secord was all it took for my fingernail to be ripped off, I reckon that Cockie must have got hundreds of them. I think even 2 mates in primary school were victims.

Been a while since being electrocuted, hopefully won't get another go at it.

[vege-mity-mite]

1) use a isolation transformer
2) use a ELCB
3) never assume it's safe until you've checked twice (y'lknow, like Santa and his list...)

Question - I'd buy an isolation transformer if it was safer, but is it? It stops grounding yourself, but if you electrocute yourself there's no ground fault sensing circuitry to protect you.

[Gentleman]

If your electrocuting yourself as often as you say then I would have one of those big red RCD's in the middle of your Workbench at all times. This forces you to plug into it everytime and reminds you, you have power off right there within your reach plus its an RCD that will protect you from faults, won't protect you from stupidity though, still can get zapped but if it's right there in your face, may remind you each time you plug in to be careful! ps. you need an isolating transformer...doh!!

[rick]

I keep my electrocutions down to once every 15 years
Or so

The point I was making is it can and does happen
And most usually when your tired
So if just one guy read the thread and said
Hmmm at some point
Better then if you didn't.

[Alastair Reynolds]

Actually to be pedantic here, we are talking about electric shocks.
Electrocution is only when death occurs.

[rick]

yes well i play the electrical guitar as well ,
its my forum i can up sell my stupidity anytime i like !