# how much current?

Discussion in 'General Electronics Chat' started by Mathematics!, Feb 26, 2010.

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1. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
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Ok , I am trying to figure out what the average current that will flow if you touch the hot wire (120 vac ) only at the black wire with rubber boots on?
In other words what ohm value can I use to approximate the human bodies resistance while where shoes?

Also if you don't ground yourself you will be ok by just touching the hot wire.
However other then not touching metals what other material could ground you if you where wearing rubber boots? (Like is their some nonmetal that is a conductor or are metals the only types of conductors and everything else is either an insulator or semiconductor....

Thanks and I don't recommend trying this but please don't lock this post.

2. ### SgtWookie Expert

Jul 17, 2007
22,194
1,763
Ahhh, you don't touch the black wire if there is a way to possibly avoid it.

You have to understand; we try to teach safety here - not inviting disaster.

If you're not more careful, you may wind up being a Darwin Award winner.

Beenthere closed the other similar thread for a reason. Just know that what you are talking about is extremely risky behavior, and you may be rewarded by a slow ride to the morgue if you don't put these ideas out of your mind.

The master electrician you were speaking with had many decades of training and experience. You are a neophyte. The safest thing for you to do is to stay away from mains power until you have received adequate training in that area. Talking with an electrician for a few hours does not make for adequate training.

3. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
I understand this....
But I still want to know why the math is not adding up...

Is their still small amounts of current flowing thru you to the ground or is the rubber boots stopping current completely to ground under you?

Rubber has a certain resistance and the human body's resistances + the rubber resistances is mathematical not infinity so by ohms law their would always be some current flowing thru you if you touch the black wire.

Is the reason why we don't get hurt is because in this case the human + the rubber is to much resistance to draw a lethal current from the 120vac source. But if the shoes where off and we are standing in water then the resistance would be alot lower and we would be in the lethal current range .

This is the only way I can see it being unless ohms law is wrong?
Either way if I am right then current is flowing thru you when you touch the black wires regardless of how much resistance you and your rubber boots are provideing... (be it lethal or not)

4. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
Yes , I understand where you are coming from but can somebody tell me if my logic was correct or not (the math say's current is going to flow regardless of how much insulation you have.

Unless you can some how provide infinity resistance in some way.
Their will always be current flow once you touch the hot wire.

5. ### SgtWookie Expert

Jul 17, 2007
22,194
1,763
There is going to be some current flow.

Work boots are available with a fairly high insulation rating. However, they are not perfect insulators. You wouldn't be able to measure the resistance value with a typical multimeter.

6. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
Thanks
One other thing I don't understand is on some street transformer buckets.
They have a wire running directly to ground down the pole and some transformer poles do not have a wire run directly to ground.

Why is this?
I heard from a line man that installs this and he said they usually install a metal stake 6ft or more under the ground on the transformer buck poles but could not tell me why some of them are missing them?

anybody know?

Last edited: Feb 27, 2010
7. ### Audioguru AAC Fanatic!

Dec 20, 2007
9,450
910
Don't assume that rubber boots are an insulator. Maybe the rubber has carbon in it to make it black or has anti static-electricity conductors in it.

8. ### SgtWookie Expert

Jul 17, 2007
22,194
1,763
AudioGuru,
That's basically what we're talking about here. We don't want people to get the idea that it's safe to monkey around with live mains power. The master electrician would be wearing work shoes/boots that had a specific rating for insulation. Common street shoes/boots do not generally have such ratings.

Leather soles, when damp, have about the same insulation value as skin. You might as well be barefoot. As far as other shoes/boots go, unless they came with a specific insulation rating, you have to assume that they will be conductive; and therefore it is unsafe (and very unwise) to risk your life by working on live mains circuits.

9. ### WIRE BENDER New Member

Aug 30, 2009
1
0
OK Guys, what about capacitance ?
Wire Bender

10. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
you have 2 black wires at the ends of the transformers low voltage side on the pole which gives you 240volts between them then you have
another white wire as your center tapped wire. But how is this white neutral wire common to the ground unless it is always touching the ground in someway. (by using the metal stake ofshoot method to make it common to ground)

In reality the transformer from black to black wire has nothing to do with ground the white to black wire would only have physical ground as one of the circuits paths only if one of the white wire was common to ground. And to do this off of a transformer would mean grounding the white wire to physical ground before sending it to your house

Because realistically you have to complete the circuit and if the physical ground wasn't involved then you would have to physically touch the black to black wire or white to black wire to complete the circuit

Thanks

Last edited: Feb 27, 2010
11. ### PackratKing Well-Known Member

Jul 13, 2008
849
218
Math............it boils down to this........

You mess with the Bull............ [ 120 vac mains ]

Sooner or later you're gonna get the horn.

Been there..........done that. I'm still here to say 15 amps bites awful hard.

Intentional electric shock, debilitates nerves in muscle tissue. Google the medical aspects of electric shock / electrocution. Permanent physical symptoms similar to MS, involuntary spasms, the list is long.

You seem an intelligent person. Please direct your curiosity in other directions, and take for granted that current does indeed flow under parameters you mentioned.

I vote for closing , if not even deleting the thread.

Last edited: Feb 27, 2010
12. ### beenthere Retired Moderator

Apr 20, 2004
15,815
290
I will agree that enough has been said.

It is odd that these discussions seem to turn into a sort of exersise in brinksmanship. "If I am wearing two pairs of socks and the water is not quite up to my ankles, then I won't get a fatal shock when I touch the 480 volt buss bar".

There is never any reason to take chances around electricity.