G-J-B

Had family over to visit, and my father was collecting up the long extension cable plugged from the barn to the pool, when the two prongs of the plug stuck to his arm and electrocuted him and stuck to him for several seconds until he could pull it off with his other arm. Fortunately after a hospital visit he is fine, just a burn to the arm, and they released him early rather than leaving him over night.
I feel as guilty as hell, as normally I would have gone over to the barn and unplugged it from the socket first, but I'm still surprised it might have electrocuted anybody. It was bone dry, and I've used the cable all summer (it had been used by the previous owners for years previously). Is it normal that an extension cable plugged in at one end could electrocute somebody who accidentally touched the two prongs, or could there be some fault somewhere? One pompier looked at the plug and said he'd never seen it happen before, though a doctor at the hospital said it was foolish and should have been unplugged first.

dennerlymum

phew! Glad your Dad is ok; would not have imagined that someone could be electrocuted like that: we have an extension lead to our pool as you describe and during work recently didnt disconnect it ever... it makes you think!

Ka Ora!

What electrical device/s were plugged in at the other end, And or had the extension been coiled up prior to being unplugged in the shed.

Sounds like a bunch of capacitors discharged the wrong way from a electrical device plugged in at the other end and your FIL became earth point, Or part of a Ground loop. Try repeating the conditions but instead of earthing the extension lead by a person use a good multi meter You may find a faulty device was plugged in creating the conditions for stray capacitance and inductance.

Peabrain

Me not understand. If it's an extension lead plugged into the mains at one end, how can there be "prongs" on the other? There should be holes, shouldn't there, or have I missed out on something all these years. In addition the "female" end should be protected (down boy) by a load of insulation, shouldn't it? If it's as old as you suggest, perhaps it's time to get another one. Shouldn't the disjoncteur have tripped too?
pb

Ka Ora!

He said "Prongs of plug" not "Prongs of socket"

Peabrain

Oh

cuthbert

Do you have any other supplies to the barn and are your electrics protected by a residual current device, (a breaker saying something a number like 30A 16A and then written in small print 30mA on it somewhere)? and as per Ka Ora it's important to know what you had on the other end.

G-J-B

Cheers for the replies. I'm not very electrically minded. It's a black and decker extension cable on one of those drum reels. On the end of the extension is a further tiny white extension lead that provides the two male prongs (female to male converter type), that plugs into a waterproof socket outside a wooden box. On the inside of the box is a switch next to the pool filter to allow you to switch the filter on and off without manually pulling out the plug and putting it back in each time.
Our electrics look a bit out of date, but it's all properly fused (16A marked on the box), and passed the diagnostics test done just over a year ago. The extension was still plugged into the barn and the mains electric, and my father had pulled it out from the pool end, and was just wrapping it around his arm to bring it inside (which I have done on a number of occasions myself, to move the cable out the way of the mower). We were just talking about hornets at the time, as we'd seen one in the pool and he started screaming (he's a man with a high pain tolerance I'd never heard him yell out in pain before). He collapsed to the floor, and I touched him (in hindsight not so clever!) just after he'd pulled the plug off him, as I thought he'd been stung and had had some strange instant reaction. Hadn't occured to me he might have electrocuted himself. The two prongs made a nasty electric burn to his arm, which has been treated at the hospital.

Ka Ora!

A female to male electrical converter is a real no no, A young child could stick that in their mouth with horrific results as there seems to be no rcd protecting the circuit. Get a sparky in and get it modernised.

G-J-B

We have three RCD's installed on our electrics box (unless I'm confusing these with a circuit breaker - do they look the same?), and they worked when the house was struck by lightning recently, but will definitely be getting an electrician in to check it out, and will not be using the female to male electrical converter again.

Im_and_Er

I'm throughly confused with your configuration of extension leads and female to male adapters etc. but If the far end (load) was still connected and your father unplugged the extension from where it was plugged into the power, and than got his shock from the prongs of that plug, then it sounds like he may have experienced a perfectly normal phenomena called back emf.

Back emf can be generated in several ways, the collapsing magnetic field from a motor such as may be used for a swimming pool filter, being one.

Another possibility is if an extension is still tightly wound up when it is energised it too can generate it's own magnetic field which again can cause a pulse of back emf when it's unplugged and it collapses. Such stored energy will normally dissipate very quickly and is rarely a problem but if the prongs of the plug happened to come into contact with a low resistance surface in that time, such as human skin, it effectively makes an easy circuit for the energy to discharge resulting in a shock or a burn.

If this is what happened then I think he must have come into contact with it almost immediately after unplugging though as under normal non fault conditions I wouldn't expect the energy to create back emf to last for more than a couple of seconds at the very most.

The simple answer to avoid getting a shock from a plug in these sort of situations is to leave it for a few moments after unplugging for any energy to dissipate naturally. You should also always fully unwind an extension.

Peabrain

Jeez, you were lucky, as it would appear this all took place near a pool; just as well the ground was dry. The trouble is when one buys a property one discovers through trial and error what corners were cut by previous owners. I bought this place off a bloke who was a total stranger to DIY, which I thought was a good thing. Trouble is, he had vital things like the electrics done by amateurs, and although there is nothing here as crass as having live prongs sticking out of a plug just waiting to electrocute some passing relative, I've had to have the whole lot redone, by a professional. The usual scratching of heads, rolling of eyes, sucking of teeth, "mais ça va pas du tout" / "je comprends rien à ce bordel", / "mais qu'est-ce qu'ils ont voulu foutre ici" etc and a hefty bill at the end. Worth it though, for one's own peace of mind, and comfort.
Is there a reason why your pool filter system doesn't run automatically, rather than manually? I've always been told that water has to be filtered daily in season, otherwise it'll 'go off'. (an opening gambit for a lengthy thread about maintenance of pools..)

G-J-B

Thanks for the replies Im_and_Er and Peabrain

The extension was completely unwound. One end plugged into the mains inside the barn, the other end had a foot long converter which then plugs into a waterproof socket next to the pool. This allows me to plug the filter into an internal socket, with a seperate switch, so that when I need to change the filter settings, I can simply hit the outdoors switch to turn off the power first, rather than unplugging the power cord itself.

When we first moved in 3.5 months ago, EDF popped over, and the guy said we might need more power for the house. We got the local electrician to come over, and he didn't think it had been done very well, though it would suffice for the moment. He was supposed to get back to us with a quote, but we never did hear back from him. I will call out another electrician soon to come and take a look - even if it costs a small fortune, human lives are more important than expenses.

Im_and_Er

I think I understand what you've done - I don't like it if I do but thats something else.

So it was the plug in the barn which he had removed from the mains that he got his shock from yes ?

G-J-B

No, it wasn't the plug from the barn end, it was the end of the extension cable (out in the garden, near the pool) as it was being removed and wound up to bring indoors. It wasn't my set up - the house came with the pool and that's how the previous owners had used it for many years.