On 7/22/2014 2:06 PM, wrote:
On Tuesday, July 22, 2014 12:28:45 PM UTC-4, amdx wrote:
On 7/20/2014 11:33 AM, wrote:

On Saturday, July 19, 2014 5:50:58 PM UTC-4, John G wrote:

explained on 20/07/2014 :

Where ever it is measured on the property MINUS VAR. Because that's resistance of volt amps.



Anything below 5 millivolts is not harmful to persons/property (including VARs). Its in any NEC.



In other words, the more metal there is between that 5mv+ and the main panel's box,



itself the more potential to a path back (which means less potential for

a live person to get in the way)

Most of what I snipped was wrong or not understandable.



Higher voltages are more apt to deliver more current through your body,

PERIOD.



One thing I think I see you saying is, you are placing your body as the

return line for the 240V device. So if we consider a TV that uses

120 Watts, At 240 volts the TV would draw 500 milliamps, at 120 volts

it would draw 1000 milliamps. If you put your body in the return line

you might think you are safer at 240 Volts.

The resistance of the human body in contact with a electrified metal

part can very greatly from 500 ohms immersed in water to 1 million ohms

on dry skin. So I'll pick 15,000 ohms for each body/conductor

connection, for a total of 30,000 ohms.

A 120 Watt, 240 volt TV is equivalent to a 480 ohm resistance.

A 120 Watt, 120 Volt TV is equivalent to a 120 ohm resistance.



If we add the TV's resistance to the body/conductor connection we get,

30,480 ohms for the 240 Volt circuit, and 30,120 ohms for the 120 Volt

circuit.

If you do the math, the 240 Volt circuit has a current flow through

your body of 7.8 milliamps.

The 120 volt circuit has a current flow through your body of

3.98 milliamps.

Using your 5mv number 240 Volts is deadly, 120 Volts is not.



If I did not understand correctly that your thinking is, "you are

placing your body as the return line" then all of the above is still

relevant but may not have given you the info you need for understanding.

If you don't understand how I did the math to get the numbers please

ask and I will type it out.

The whole problem is that no one here is mentioning the NEC. Don't use your own figuring. Instead, use examples from the NEC. Discard your "figuring".

Here is something from an NEC study guide which is what I meant.

"Nonmetallic boxes are not permitted to be used with a metallic wiring method because there is no way to maintain the electrical continuity of the effective ground"

-- http://www.mikeholt.com/mojonewsarch...s~20050510.php (2nd question - answer)


Here is what you said that many of us disagree with. "Overhead
commercial lighting voltage is 277 so its less current and less
dangerous" (than a lower voltage, higher current) I added the line in
parentheses because I think that is what you meant. Is that correct?

What does your link have to do with higher voltages being safer?
Mikek