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Got shocked by 120VAC

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ledtester:
Two quick anecdotes...

I watched as HVAC installer get shocked several times as he replaced a controller for a boiler. He couldn't find the fuse for the controller circuit but decided to proceed with the replacement anyway. He talked as if it wasn't the first time he had done this.

An electrician was called in to add a ground wire to a circuit. When he turned the circuit back on a loud pop came from a VCR. Turned out he had wired the circuit for 240V instead of 120V. Fortunately the only casualty was the VCR.

--- And you could say we were very lucky the VCR popped alerting us to the problem while the electrician was still around.

Mark:
I have a reference book that tells me that anything up to 100V is fine to handle.  Up to 200V should be handled with caution. 
400-500V should be regarded dangerous. 
You might get a shock from 100V if you were standing on a wet floor and had wet boots and wet skin. 
If the conditions were reversed, up to 300V might not do any harm. 



The above information might be a bit out of date, it comes from "POWER AND ITS TRANSMISSION, A practical handbook for the factory and works manager" by Thomas A. Smith, 1910.   ;)

Zero999:

--- Quote from: Mark on June 07, 2021, 09:19:12 am ---I have a reference book that tells me that anything up to 100V is fine to handle.  Up to 200V should be handled with caution. 
400-500V should be regarded dangerous. 
You might get a shock from 100V if you were standing on a wet floor and had wet boots and wet skin. 
If the conditions were reversed, up to 300V might not do any harm. 



The above information might be a bit out of date, it comes from "POWER AND ITS TRANSMISSION, A practical handbook for the factory and works manager" by Thomas A. Smith, 1910.   ;)

--- End quote ---
It's clearly out of date. They were much less bothered about safety 100 years ago, than today.

Those voltage sound way too high. Are they mains frequency AC, or DC? DC is less hazardous, than mains frequency, given the same current/voltage. I'm generally more careful, when the voltage gets above 60VDC, or 25VAC, purely because that's what the safey standards say.

Siwastaja:
It's all about probability distribution and how that compares with other risks around us.

In 1910's, it was considered normal to just die out of unknown disease for no reason whatsoever.

If you compare to that, if you receive one hundred 100VAC electric shocks during your career and each carries a risk of death of, say, 10-100 ppm, you are most likely still alive, and way more likely dead due to all the other safety issues in the society.

The risk of death is still the same today, but we just expect higher level of safety. In most usual dry conditions, 100VAC is a very small risk, but a real risk nevertheless.

People were not extremely stupid back then, still. Unnecessary and large risks were not routinely taken. That is why you won't find a citation saying 230VAC is safe to handle. It is so much more dangerous, even on yesterday's standards.

BradC:

--- Quote from: LECKO on June 05, 2021, 03:07:29 pm ---These too operated at 25 volts DC, take it from me it hurts when your hands are wet from dripping salt water!!
--- End quote ---

I was working in a stinking hot bilge, dripping with sweat and kneeling on an earthed intake strainer that had just flooded with salt water. The 10mm spanner in my hand that I used to tighten the nut on the back of the 24V alternator let me know in no uncertain terms that with sufficient skin surface area and conductivity low voltage can hurt like hell.

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