Question about electric shock

[dylan3789]

I'm hoping someone can help me out.

At the weekend, I did a stupid thing, and that was to try and fix a light fitting without turning off the electrics. I know I'm going to be told that I shoudn't be touching anything electrical without doing so and that I have no business doing electrical DIY if I can't do a simple thing; I've never done anything this stupid before and I can't really explain why I didn't turn things off - except that I wasn't dealing with bare wires or anything so it just didn't cross my mind.

The light fitting is one I put up the other day; it's a hanging pendant light and the issue is that the glass shade and the bayonet bulb holder weren't aligned and the bulb holder is a bit wonky. I gripped the holder after unscrewing the outside part and was trying to straighten it when the palm of my hand must have touched one of the bayonet connectors and I received an electric shock. I was wearing trainers at the time and standing on a wooden chair. I felt my arm shake/move and it went up to the side of my face, which also felt like it was moving and rippling strongly; this lasted for 1-2 seconds and I let go.

I felt fine afterwards but went to A&E to get checked out; they did an ECG and tested for any muscle damage that might show up in a blood test (apparently a serious enough shock and cause muscle to break down and this builds up in the bloodstream).

What I'm trying to establish is how much current was likely to have gone through me. I know that resistance can depend on a lot of things; my hands were dry at the time and the connector touched the centre of my palm, where the skin is quite thick. I'm guessing the electricity passed down my arm and into my face, rather than down my body, because there was a lot of resistance between me and the earth. I did wonder if it went to my face because there are amalgam fillings in some of my teeth but I don't know if that's really likely.

I'm trying to work out how serious a shock this was, as the doctor I saw in A&E was very concerned about possible internal damage that can't be seen, and in his opinion, the absence of an entry/exit wound doesn't necessarily mean all is completely fine. If I only touched one connector, is that 120 volts or still 240? I didn't get thrown about/off the chair and I was able to let go of my own accord once I realised what was happening.

I'm not worried too much about internal damage, to be honest, as I do feel fine; I'm more interested in trying to establish exactly what happened as it's made me realise that my knowledge of electricity in the home needs to be better. And yes, I always need to turn off the fuse - so please don't reprimand me for not doing so: enough people have already told me off!

Any advice would be great, thank you.

Dylan.

 

[HandySparks]

With electric shocks, it's the amperage which causes the biggest problem.
Higher the amperage the more severe the damage.
With a live circuit the amperage will be a combination of how much can flow through your body plus whatever amperage is already on the circuit.
Lighting circuits are generally rated at 6A, but rarely run anywhere near that.
If you allow 100W for each light, it would give you just less than half an amp per light. 60W about a quarter of an amp.
So if you know how many lights on the circuit were on at the time you received the shock, you can calculate the amperage on the circuit.

This is a wind-up.......isn't it?

 

[Darkwood]

Can we stick to answering the OP question, we are slightly getting off track here with some replies.

Feel free to start a new thread/pole regarding members and how many times they have had a shock

 

[westward10]

With electric shocks, it's the amperage which causes the biggest problem.
Higher the amperage the more severe the damage.
With a live circuit the amperage will be a combination of how much can flow through your body plus whatever amperage is already on the circuit.
Lighting circuits are generally rated at 6A, but rarely run anywhere near that.
If you allow 100W for each light, it would give you just less than half an amp per light. 60W about a quarter of an amp.
So if you know how many lights on the circuit were on at the time you received the shock, you can calculate the amperage on the circuit.

Is this serious!

 

[telectrix]

this thread is shocking. time for closure.

 

[westward10]

The amount of current which flows is dependant on body resistance and the applied voltage. This body resistance will be dependent on where across the body it flows, hand to hand can be very hazardous as it is likely to bring the heart into the equation. If you are wet the body resistance will be reduced dramatically and hence more current will flow this is why bathrooms and swimming pools are Special Locations due to increased risk. Simple ohms law and we are all different.

 

[Deleted member 26818]

So if you were to insert yourself into a circuit which already had 20A flowing through it, how much current would flow through you?
Would it be more or less than the 20A?

 

[Silly Sausage]

So if you were to insert yourself into a circuit which already had 20A flowing through it, how much current would flow through you?
Would it be more or less than the 20A?

Less than 20A, depending on your resistance, but how often do you put oneself in series in a circuit?!
Remember, touching an energized whatever, you're in parallel with said whatever.

 

[westward10]

So if you were to insert yourself into a circuit which already had 20A flowing through it, how much current would flow through you?
Would it be more or less than the 20A?

Will depend on body resistance at the time, your resistance will restrict the 20A current. It certainly won't be 20A.

 

[Deleted member 26818]

So what happens to to rest of the 20A?
Does it just fade away?

 

[Richard Burns]

If you were to insert your body into a series circuit that previously was carrying 20A then you would be adding (approximately) 1000 ohms resistance into the circuit, this, compared to the 11 ohms that was there before, would reduce the current to about 0.23A to flow through you.

The way I see it is the problem with electric shocks is that the current will make a path through you and cause damage to the cells of the body. This is the part that causes significant damage internally.
However this is generally only encountered where the current can be high enough to kill and the voltage high enough to jump across inconveniently high resistances in the body.
The electrocution effect is stopping the heart which may not cause a lot of damage to cells but does tend to kill outright.

Most of the shocks that some people receive will be very low current (above 10mA) perception limit but below the 50mA (or so depending on time) killing level.
Time is a key component in both death from electric shock and cell damage.

 

[westward10]

So what happens to to rest of the 20A?
Does it just fade away?

You are putting your body, wish it was mine at the moment in series and as Richard states use a 1000 ohm resistance, apply ohms law and the current flow becomes approximately 0.23A assuming a 230V potential, it don't disappear.

 

[Darkwood]

Your body resistance when dry can be as high as 80,000 -100,000 ohms but as low as a few thousand wet, so many variable also can effect this figure like your health, skin conditions or even whether your wearing anything topical like a cream.
Once the electricity has broken down the skin which LV can do quickly then this quickly drops your resistance as low as 300-500 ohms if the entry exit points remain the same.
Like mentioned before, mostly when you receive a shock you are parallel to the supply and earth, N or other phase and thus you will be getting the full supply through your body, currents as low as 1mA can set your heart in to fibrillation if your unlucky enough to have the current pass through it and as the heart is a main junction of your blood vessels then its a risk many have lost their lives to, like most sparks Ive have many a shock over the years and the majority I can honestly say were not through my own stupidity but even though we can carry the career scars of numerous shocks I would never get complacent to its potential (no pun intended) to kill you, it only takes it to find that route of least resistance through your heart and even a mild short lived shock can be you end of days.


Its easy to assume 30mA is a safe value due to RCD's been labled for personel protection but they are this rating as its a balance between protection and nuisance tripping but even a fully functional RCD cannot stop electricity killing you as it is only there is reduce the chance of serious/fatal injury.

I must also add that 230v is a mean of the AC waveform and your body will be subject to the peak voltages which are much higher so this will further speed up the breakdown of skin resistance.

 

[gatuka]

The first time I had an electric shock I got an erectiom which lasted for 5 hours and when you get an electric shock I thought you get 30milliamp and the RCD trip

 

[Darkwood]

10/10 @gatuka for the most unexpected post that I have seen on the forum in a long time

 

[Pete999]

So what happens to to rest of the 20A?
Does it just fade away?