Touching pos & neg of battery

penberth3 said:
Why?
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I always stripped cables with my teeth in those days.

I pulled the lawn mower extension cable too hard and ripped the socket off.

I thought I'd unplugged the other end when I went to get a screw driver.

This thought did not equal action!

Now I like to see both ends of the cable if at all possible.

I have a friend here in Plymouth dockyard who still tells my sad tale to new engineering recruits. The motto being; don't make assumptions, they sometimes hurt!
 
john_morris_uk said:
I also used to strip wire with my teeth and once started to strip some mains twin flex that had 240 AC on it. I wasn’t in wet grass but I jumped a fair bit and got a blister on my tongue...
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It would usually be fairly safe to touch live and neutral on the tongue, because the current will follow the most direct path, but as you noticed, it would probably result in a localised burn. The most dangerous kind of shock is one where the current flows from one arm to the other, because current will flow through the heart, disrupting the rhythm, and so causing cardiac arrest.
 
elton said:
It would usually be fairly safe to touch live and neutral on the tongue, because the current will follow the most direct path, but as you noticed, it would probably result in a localised burn. The most dangerous kind of shock is one where the current flows from one arm to the other, because current will flow through the heart, disrupting the rhythm, and so causing cardiac arrest.
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It was twin flex with no earth.

I agree about it being more dangerous when the milliamperes pass through substantial parts of your body.
 
elton said:
It would usually be fairly safe to touch live and neutral on the tongue, because the current will follow the most direct path, but as you noticed, it would probably result in a localised burn. The most dangerous kind of shock is one where the current flows from one arm to the other, because current will flow through the heart, disrupting the rhythm, and so causing cardiac arrest.
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That's some obscure variety of 'safe' that risks blowing a hole in your tongue and possibly killing yourself?
It's quite plausible that you'd spasm and then the current could flow anywhere the wires landed.

You can feel the effects of a 1.5Vbattery on your tongue.
ISTR a 9V battery is damned unpleasant.
I once got a bit of a tingle drinking from a tap at a sailing club. Not pleasant!
I put a multimeter on it and saw about 10V with not much current behind it.

Normally you can touch up to about 50V with your hands and not feel it. But over a short distance of flesh, it can be felt, can cause burns etc.
It only takes 1.23 Volts to electrolyse the water that we are largely made of!
 
You certain you've felt 12V?

I have touched many many battery terminals with wet hands when messing around with everything from boats to annoying cars, and never ever felt a thing. Infact, I might put some salty water on my hands and have a go with the bench powersupply tomorrow, that goes up to 60V.

From experience, with dry hands, 100V is noticeable but not hugely unpleasant. 50V is not even noticeable. I'll give it a go with wet salty hands and let you know.

The biggest danger is not, as someone said, the battery exploding .. the biggest danger is the spanner that is in your hand gets red hot and causes a serious burn.
 
"It is possible to get a shock from a 12v battery" ... well, I've been doing electronics for ... oh, 40 years, regularly come into contact with various voltages, but I have never, ever felt anyting off a 12V source, even with wet hands, and prior to this thread, never come across anyone who has ... and to be honest, I'm not conviced.

I've got a 60V variable PSU on the bench at work ... you know what I'm going to be doing don't you?
 
Boo2 said:
Linky ?
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I use a "Dis-car-nect". A tenner from Amazon: https://www.amazon.co.uk/Richbrook-1000-01-Discarnect-Immobiliser-Battery/dp/B0019ULCPW

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The fused link is so that you can keep clocks, alarms and so on running while the battery is disconnected for high currents. An anti-theft device, basically. I've never bothered with that bit.
 
davidej said:
You can buy ( cheaply) terminals with an isolation switch on it .I have fitted one to a classic car to avoid running down the battery when i am not using it for some time.
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I would highly recommend this. 12V is harmless, you'll never feel it ... but a red hot piece of wire covered in melting plastic is another matter! Most (all?) boats have a batter 1-2-off battery jumper/isolator, you might be well advised to turn it to the off position when messing around with the electrics ...
 
Lon nan Gruagach said:
all right, fess up, when was that last time you put a 9V battery on your tongue?
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I do this fairly regularly - good way of testing whether the battery is good or not (although 9V batteries are getting rare these days)

As to 12V I would not normally think anything of holding both terminals (e,g, hold test probes against each, but I do remember noticing once when my forearm came into contact with both terminals
 
rszemeti said:
"It is possible to get a shock from a 12v battery" ... well, I've been doing electronics for ... oh, 40 years, regularly come into contact with various voltages, but I have never, ever felt anyting off a 12V source, even with wet hands, and prior to this thread, never come across anyone who has ... and to be honest, I'm not conviced.

I've got a 60V variable PSU on the bench at work ... you know what I'm going to be doing don't you?
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What would i know. Welcome to the forum, it's nice to have another member to tell me i don't know what i'm talking about :encouragement:
 
RichardS said:
I think that, in general, Rszemeti is agreeing with you and me in being sceptical about the possibility of getting a shock from a 12V battery. Maybe a tingle if you try really hard. ;)

Richard
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Sometimes hard to tell on PBO Richard :)

It's certainly fair to say you won't get fried by touching the terminals of a 12v car battery, but it definitely is possible to get a shock, in the way you get a shock by sticking your tongue on a small battery, rather than getting hurled across the room and dying a horrible death.

I was somewhat surprised to get a couple of 24v shocks on one boat in the Summer, i've been in situations where there have been 240v earth leaks (pre-RCD days) and people have complained about getting shocks from the wall, where i could not feel them.
 
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