Thought This Might Be Interesting...

Talk Electrician Forum

Help Support Talk Electrician Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Mar 12, 2011
Messages
3,608
Reaction score
180
Location
Psychiatric ward??
Hi all,

You often hear talk about what voltage will kill you...

It is not surprising that is you were immersed in water a LOT lower voltage would be needed to deliver a fatal current flow, but how MUCH of a lower voltage....

Read this and be shocked.... [you will be...]

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763825/table/T4/

Have a read of this too;

Measurements similar to those of Smoot and Bentel12 were done with approval of the institutional review board of University of Illinois in Urbana-Champaign. Metal plates were placed inside rubber containers. The metal plates were flat on the bottoms of the containers. A rubber mat with holes was placed on top of each metal plate. An (isolated) power source ground wire was connected to one plate, and a 60-Hz AC voltage from the power source was connected to the other plate. The subject stood with 1 foot on each rubber mat, as shown in Figure ​Figure5.5. Thus, the subject's contact with electric current was primarily through the water contacting the feet through the holes and also through water contacting the legs higher up. This foot-to-foot current path simulated the hand-to-hand and hand-to foot situations that can occur with swimmers in water. This setup minimized current flow through the chest. The study involved just 1 subject.

Figure 5
Measurement setup for voltage and current in water.
Fresh (not salt) water with conductivity of 320 µmho/cm filled each bucket to a level near the hip. It was found that electrically induced muscle contractions were greatly modified by leg position in the water.

Initial testing has shown that with 3.05 V (60-Hz AC rms) applied between the plates, a current of 8.65 mA flowed, resulting in involuntary flexion of the knee to 90°. This flexion could not be overcome with voluntary effort. The knee could be flexed further voluntarily, but it would not straighten beyond 90° of flexion. The involuntary keen flexion occurred when the leg was lifted (by hip flexion) so that the thigh was horizontal and the knee was at the water level. This is similar to the situation when one is swimming. Muscle control was gradually regained when the foot was lowered to the bottom of the bucket (by hip extension to the neutral position) and the leg became vertical. Total body resistance would be calculated as follows:

At 4.05 V, a current of 12.6 mA flowed. The knee was flexed to 135°, meaning that the heel was near the buttocks. This could not be overcome with voluntary effort. Again, this occurred when the leg was lifted so that the knee was at the water level, similar to the situation when one is swimming. Lesser impairment of muscle control was noted at other leg positions. Muscle control was gradually regained when the foot was lowered to the bottom of the bucket and the leg became vertical. The resistance would be 4.05 V/12.6 mA = 332 Ω

Read the entire article here...

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763825/

Last time i EVER go in an electric shower...... not interested in what bonding they got....

john....

 
Last edited by a moderator:
I've posted this before but its worth it again .    To experience mains voltage through the body is frighteningly awesome  and not to be recommended  .

Not received many shocks TBH  but about 6 years ago  I was adding a fluorescent fitting  above a printing press.

We had fitted plug-in lighting trunking  the length of the 6 colour press ...you hook the fluorescent fitting onto the track  ...fitting has a 2 ft  flex & special plug that fits the trunking outlets .  

So up the tall steps ..hook the fitting on ..... hold plug in right hand , grip trunking with left to stop the trunking swinging about on it's long tthreaded rod drops.  

I didn't know that the clear plastic cover over the  3 terminals in the plug was missing ..... I didn't have my glasses on so everything within 1 mtr is blurred ..

  My thumb is on the terminals as I push the plug into the socket ...I havn't turned the track off because ....what can go wrong !!!!.... :C   I can still feel the power surging across my chest TBH... chest muscles seemed to cramp up  ..... apparently I cried out .... couldn't loose the track until I somehow  loosed ... and somehow slithered down the 8 ft steps .

The overall feeling was being in the grip of some hugely powerful force for a few seconds before it seemed to fling me aside   :eek:     

 
That was probably a close call Deke.

Most of us will have had a shock or 20, but usually across the end of a finger where it hurts, but is unlikely to kill you.

 
Oh God..... Then you will not want to read my latest post then....

Tin hat very firmly on!!!!!

A lot of the people near me have had their sheds and garages broken into in the last few weeks. We all know who did it, the one and only local burglar. He will be in jail for years, then, they will let him out and there will be a month long crime wave. Last time the police [well, their dog] actually caught the bastard IN my car!! That was purely by chance too, they had let their dog go for a sniff about 500 yards away, and the thing ran straight off to my car..

Anyway, I want to make an electric fence to keep the bastard out. A proper one is about £250 and just lets out a pulse every second or so….

Now.. I have a transformer here….. what I want to know is, is this thing lethal, or will it just severly hurt the twat..

The thing is wound for 400v on the primary and 10Kv [rms] on the secondary [14Kv peaks] at 20mA

If I run it at 230v this equates to 5.75Kv with 8Kv peaks… Does it follow that the current on the secondary will now be 11.5mA or does it not work like that.

How not nice would 20mA at 14 Kv be???? What about 11.5mA at 8Kv ????

A car ignition coil would be about 5mA at 10Kv and that is not nice at all, so I thought about double this would be just right..

But, and it is a HUGE but, an ignition coil delivers a DC shock of very short duration, this transformer delivers a continuous AC shock, VERY much more dangerous, unless of course you only hold the thing for one half cycle, when I presume it will be the same as dc!!!

[SIZE=12pt]Not sure what to do now!!!![/SIZE]

[SIZE=12pt]john......[/SIZE]

 
Yes ...and have you noticed how fast many sparks react to a bang behind them ........specially when they have their hands inside a panel or board .

There was always that jolly jape when fault finding on a live panel ...or just about to poke your mains testers in ..when some clever wag claps his hands behind you & shouts  BANG!!!!! 

Oh God..... Then you will not want to read my latest post then....

Tin hat very firmly on!!!!!

A lot of the people near me have had their sheds and garages broken into in the last few weeks. We all know who did it, the one and only local burglar. He will be in jail for years, then, they will let him out and there will be a month long crime wave. Last time the police [well, their dog] actually caught the bastard IN my car!! That was purely by chance too, they had let their dog go for a sniff about 500 yards away, and the thing ran straight off to my car..

Anyway, I want to make an electric fence to keep the bastard out. A proper one is about £250 and just lets out a pulse every second or so….

Now.. I have a transformer here….. what I want to know is, is this thing lethal, or will it just severly hurt the twat..

The thing is wound for 400v on the primary and 10Kv [rms] on the secondary [14Kv peaks] at 20mA

If I run it at 230v this equates to 5.75Kv with 8Kv peaks… Does it follow that the current on the secondary will now be 11.5mA or does it not work like that.

How not nice would 20mA at 14 Kv be???? What about 11.5mA at 8Kv ????

A car ignition coil would be about 5mA at 10Kv and that is not nice at all, so I thought about double this would be just right..

But, and it is a HUGE but, an ignition coil delivers a DC shock of very short duration, this transformer delivers a continuous AC shock, VERY much more dangerous, unless of course you only hold the thing for one half cycle, when I presume it will be the same as dc!!!

[SIZE=12pt]Not sure what to do now!!!![/SIZE]

[SIZE=12pt]john......[/SIZE]
Thing with doing that Apprentii is you end up in court , and imagine if a child grabbed hold of it .    Some guy in the midlands had his car wired to the mains , on his drive .  He maintained it was private property so he could  do as he likes , but thats not the case .

I think its the same as thumping seven kinds of excrement out of someone who attacks you ........  they arrest you for protecting yourself too violently.

 
Top