Portable hand tools

[shwazqrt]

Good Morning Gents,

I have a safety Q,

Why should the Portable hand tools not exceed 125V ?

I asked my engineer,
said the reason is that the less the (V) the more (I) and vise versa. Also said, related on how the heart works.


If someone knows please, explain to me.


appreciated.

 

[ramsy]

I believe 120vac is the most likely receptacle voltage available in the US, making any tools or battery chargers designed for that voltage most usable to consumers.

 

[LarryFine]

I asked my engineer,
said the reason is that the less the (V) the more (I) and vise versa.

An engineer should know that, for a given amount of power, voltage and current are inverse, but this requires equipment designed for each voltage. ("Watt's Law") For a given impedance, the current varies with the voltage. (Ohm's Law)

When having these discussions, you must remember what the constants are and what the variables are. In the real world, the supply voltage and the equipment impedance are factors, and the current and power are results.

 

[Lxnxjxhx]

how the heart works

how the heart works

I guess he meant current through the chest is more dangerous than current into one finger and out the other, because it may cause cardiac fibrillation.

But the danger is only loosely connected to voltage, except above 600 v or with wet skin, when you lose the benefit of skin resistance. With the currents possible at this voltage, >100 mA, the heart may be clamped so it doesn't even try to beat.

The Europeans somehow don't die with their higher voltages; I don't know if they have GFIs.

An older engineer once told me that an engineer doesn't need to know everything; he just needs to know where to look it up. I guess he didn't want to look it up.

 

[shwazqrt]

thanks

thanks

ramsy

LarryFine

langjahr@comcast.net

Thank you all . . . it was great help :roll:

but what i think is with 125V it is easy to be released when being electruted
after 1-2 seconds

with 220V it will take more seconds to release you, this happened to me for both 125V and 220V. Acutally, the reason behind that is unknown to me.

and from the sine wave, you know that it starts from zero to (peak) and down to zero to (-peak). when you being shocked by electricty your heart will either will stop for a while or try to sync with peaks, so pumps at peaks and releases at zeros. note: heart average beat 60 per min and the sine wav 60Hz


above is what another engineer said to me. Yet to be cleared.

 

[dbuckley]

In the UK all hand tools on building sites run from a 110V transformer, with the centre tap grounded, so a line to ground shock is 55V; On the larger transformers, GFCIs are now common.

Here in NZ we use 240V hand tools, but operate them off an isolating transformer with a fully floating secondary, so you shouldn't get a shock to ground at all.

 

[ramsy]

when you being shocked by electricty your heart will ..sync with peaks, so pumps at peaks and releases at zeros. note: heart average beat 60 per min and the sine wav 60Hz above is what another engineer said to me...

Thats why most commercial plans create a special line item that prohibits engineers from running jobsites. It's for everyones safety.