Would touching electric wires from the mains, kill you?

[davyboy]

I may have posted this before but it's relevant.

My father was working on the ceiling rose whilst standing on a chair with the current turned off at the wall switch.

Being a keen DIY fan (I don't think) he was using his penknife.

Enter mother into the room "it's dark in here" and turns the light on.

Flash, father swears and falls off the chair.

The tip of the penknife blade had melted.

He lived for another 20 years without doing any more electrical DIY.

Edited December 1, 2015 by davyboy

[Cyclone]

"He lived for another 20 years no thanks to your Mum" might be appropriate!

[Justin Smith]

If you accidentally touched the 2 electric (mains) wires, that connect to a light fitting; just for a split second, yes, you'd presumably get a shock, but would it be bad enough to kill an healthy adult?

 

I speak as an ex TV engineer, who has had loads of electrical shocks.

 

Assuming you were a healthy person without an underlying heart complaint, touching mains (even the neutral and the live) would be very unlikely to kill you. Quite apart from anything else, generally, when you get a mains shock it tends to make you push anything (like a wire) away from you.

I did once read that if you were unlucky enough to have the bare wire in the palm of your hand that might make you clench your hand so you couldn`t drop it, I`m unsure if there`s any truth in that.

[sgtkate]

I speak as an ex TV engineer, who has had loads of electrical shocks.

 

Assuming you were a healthy person without an underlying heart complaint, touching mains (even the neutral and the live) would be very unlikely to kill you. Quite apart from anything else, generally, when you get a mains shock it tends to make you push anything (like a wire) away from you.

I did once read that if you were unlucky enough to have the bare wire in the palm of your hand that might make you clench your hand so you couldn`t drop it, I`m unsure if there`s any truth in that.

 

Isn't that only if the current is DC? AC will pull and then push. While it wasn't designed to be safer (I believe it was due to being able to be stepped up and down with a transformer) it has had a convenient side benefit.

[Obelix]

I may have posted this before but it's relevant.

My father was working on the ceiling rose whilst standing on a chair with the current turned off at the wall switch.

Being a keen DIY fan (I don't think) he was using his penknife.

Enter mother into the room "it's dark in here" and turns the light on.

Flash, father swears and falls off the chair.

The tip of the penknife blade had melted.

He lived for another 20 years without doing any more electrical DIY.

 

ALWAYS pull the fuse from the fusebox, or lock the isolator with a padlock. Even at home.

 

And put the key or fuse in YOUR pocket so someone else cant bung it back in!

[Bottletop]

This thread reminds me of a story I read a fair while ago, some of you may remember coming across it too - I don't know if it's true though...

 

Husband is working in the kitchen on the electrics one day, wife returns home to see him holding a cable and jerking around the kitchen. She knows she needs to urgently separate him from the cable without touching him to save him from electrocution and without her being electrocuted. So she picks up the first thing she sees which happens to be a plank of wood and belts him a couple of times. He drops the cable, falls to the floor and removes his headphones, shouting "What you do that for woman!"

[Obelix]

I think it is medically proven that anything from 200mA is the KILLER, anything less may kill you, which is why electrical companies produce RCD's set at 30mA which lets fault current flow to a maximum level of 30mA for a fraction of a second until it trips the system in 400 mS.

Although any shock from an energy source whether including an RCD or not...isnt a good thing !!! I sure dont like em anyway !!

 

There are various things that affect the body. Assuming you are a healthy adult not on a wet floor etc...

 

For AC currents, a cross body shock of 200mA is not likely to kill, and higher currents are actually less lethal. This is because at this current level the heart is clamped and stops working. As long as the fault protection opens quickly the heart will restart and so will respiration. More current does mean a more severe burn however.

 

For currents around the 60mA level you will find breathing ceases and starting from 75mA upwards, the heart will enter ventricular fibrillation, with the greatest chance of this happening at about 100mA, but moving to total clamping at about 200mA as noted above. If the heart is placed into VF it will not come out, and hence the lower currents from 60-200mA are the most dangerous.

 

A cardiac defribrilation drives a biphasic shock across the chest at a current of at least 300mA. The idea is to clamp a heart in VF or VT to stop it entirely, and then let it restart normally.

 

the 30mA trip on an RCD is chose as you say to protect against these currents, but still be high enough to stop nuisance tripping. Set it too low and you start injuring people when lights go out, or they eat spoiled food from a freezer that was shut off etc...

 

Really large currents from high voltages are actually quite survivable as you are blown clear by explosion and muscle spasm, even though you can take amps of current you will live. Minus the appendage that touched the conductor of course - fingers tend to get lost in big accidents...

 

I once took a shock from a lightning strike that hit the frame of the steel clad building I was on. The absolute current was estimated at half an amp through my palm to ground thought my feet - if I'd had just my fingertips on the joist they reckon I would have lost them due to the concentration of current there. As it was I got away with just a slightly burnt palm, and a literally heartstopping moment when I fell to the ground and smacked by bonce on the floor.

[L00b]

Saw this thread, saw this post...

 

Being an ex TV repair man I've had a lot of electric shocks in the past,I think the one of the worst one was one day I was in a customers house with the back off one of those big cabinet pye TVs,when the lady opened the kitchen door and let the dog out it was a big daft spotty dog,it came running up behind me and leaped on my back pushing me with both hands outstretched into the back of the switched on TV,the one with the big glowing line output valves and lethal EHT tripler,I got a right shock the power went down my arms and because I had out of courtesy took my shoes off in the house shot through my body, I could feel my hair stand on end,I was lucky to survive that one...

 

...and it reminded me of another thread on another forum I frequent, so

for your enjoyment

[Justin Smith]

Isn't that only if the current is DC? AC will pull and then push. While it wasn't designed to be safer (I believe it was due to being able to be stepped up and down with a transformer) it has had a convenient side benefit.

 

No it`s nothing to do with AC or DC, it`s just the involuntary effect of the shock. And I can confirm its effect from all the shocks I`ve had.....

 

---------- Post added 01-12-2015 at 14:05 ----------

 

Being an ex TV repair man I've had a lot of electric shocks in the past,I think the one of the worst one was one day I was in a customers house with the back off one of those big cabinet pye TVs,when the lady opened the kitchen door and let the dog out it was a big daft spotty dog,it came running up behind me and leaped on my back pushing me with both hands outstretched into the back of the switched on TV,the one with the big glowing line output valves and lethal EHT tripler,I got a right shock the power went down my arms and because I had out of courtesy took my shoes off in the house shot through my body, I could feel my hair stand on end,I was lucky to survive that one...

 

The tripler (now long ago was that, they had LOPTXs for decades after them and they`ve gone for a good while now ! ) may be high voltage but it`s very low current. You feel it certainly, but it`d be even less likely to harm you than mains would. In my experience it`s the burn that mains can give you that is more painful (and longer lasting) than the shock. But, as it happens, when it comes to being a TV repair engineer the most painful thing is solder burns, which I`m sure you agree with......

Edited December 1, 2015 by Justin Smith

[Cyclone]

I speak as an ex TV engineer, who has had loads of electrical shocks.

 

Assuming you were a healthy person without an underlying heart complaint, touching mains (even the neutral and the live) would be very unlikely to kill you. Quite apart from anything else, generally, when you get a mains shock it tends to make you push anything (like a wire) away from you.

I did once read that if you were unlucky enough to have the bare wire in the palm of your hand that might make you clench your hand so you couldn`t drop it, I`m unsure if there`s any truth in that.

 

Current can easily cause muscle spasm, so yes, you could find yourself unable to release a conductor.

 

---------- Post added 01-12-2015 at 15:11 ----------

 

Isn't that only if the current is DC? AC will pull and then push. While it wasn't designed to be safer (I believe it was due to being able to be stepped up and down with a transformer) it has had a convenient side benefit.

 

No, that's just a really old myth that was put about to discredit DC current if I remember correctly.

 

---------- Post added 01-12-2015 at 15:14 ----------

 

There are various things that affect the body. Assuming you are a healthy adult not on a wet floor etc...

 

For AC currents, a cross body shock of 200mA is not likely to kill, and higher currents are actually less lethal. This is because at this current level the heart is clamped and stops working. As long as the fault protection opens quickly the heart will restart and so will respiration. More current does mean a more severe burn however.

 

For currents around the 60mA level you will find breathing ceases and starting from 75mA upwards, the heart will enter ventricular fibrillation, with the greatest chance of this happening at about 100mA, but moving to total clamping at about 200mA as noted above. If the heart is placed into VF it will not come out, and hence the lower currents from 60-200mA are the most dangerous.

 

A cardiac defribrilation drives a biphasic shock across the chest at a current of at least 300mA. The idea is to clamp a heart in VF or VT to stop it entirely, and then let it restart normally.

 

the 30mA trip on an RCD is chose as you say to protect against these currents, but still be high enough to stop nuisance tripping. Set it too low and you start injuring people when lights go out, or they eat spoiled food from a freezer that was shut off etc...

 

Really large currents from high voltages are actually quite survivable as you are blown clear by explosion and muscle spasm, even though you can take amps of current you will live. Minus the appendage that touched the conductor of course - fingers tend to get lost in big accidents...

 

I once took a shock from a lightning strike that hit the frame of the steel clad building I was on. The absolute current was estimated at half an amp through my palm to ground thought my feet - if I'd had just my fingertips on the joist they reckon I would have lost them due to the concentration of current there. As it was I got away with just a slightly burnt palm, and a literally heartstopping moment when I fell to the ground and smacked by bonce on the floor.

 

You seem to know a lot about this... (It's very interesting btw).