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 Post subject: The evolution of electrical safety
PostPosted: Mon Feb 22, 2010 8:44 am 
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Came across this over the weekend. This is from the 1924 edition of the American Electricians Handbook.

115 - Electricians often test circuits for the presence of voltage by touching the conductors with the fingers. This method is safe where the voltage does not exceed 250V and is often very convenient for locating a blown out fuse or ascerting whether or not a circuit is alove. Some men can endure the electrical shock that results without discomfort wheras others cannot.

116 - The presence of low voltages can be determined by "tasting". This method is feasable only when the pressure is but a few volts and hence is only used in bell and signal work. When the voltage is low, the bared ends of the conductor constituting the two sides of the circuit are held a short distance apart on the tounge. If voltage is present, a peculiarly mild burning sensation results, which will never be forgotton after one experienced it. The "taste" is due to the electrolytic decomposition of the liquids on the tounge, which produces a salt having a taste.

Wow!

Why post this? Because this shows how far most of us have evolved. Some of the old timers may have actually done this, sometimes methods like this get passed down. Obviously these practices are very dangerous and would not be followed today with anyone educated in the effects of electricity on the human body, or with a drop of common sense.

There seems to be a lot of people that hate the new OSHA and NFPA 70E rules and are reluctant to follow them. Someday, someone will be posting something similar to this talking about back in the days when we were reckless and uneducated about arc flash hazards.

After all, there was a time when 2 guys in Italy were thought to be crazy becasue they thought the earth was round.


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PostPosted: Mon Feb 22, 2010 8:55 am 
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Interesting

We use this exact excerpt during a portion of our training. Here is the whole paragraph:

Electricians often test for the presence of voltage by touching the conductors with the fingers. This method is safe where the voltage does not exceed 250 and is often convenient to locating a blown-out fuse or for ascertaining whether or not a circuit is alive. Some men can endure the electric shock that results without discomfort whereas others cannot. Therefore, the method is not feasible in some cases. Which are the outside wires and which is the neutral of a 115/230-volt, three-wire system can be determined in
this way by noting the intensity of the shock that results by touching different pairs of wires with the fingers. Use the method with caution and be certain the voltage of the circuit does not exceed 250 before touching the conductors.


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PostPosted: Mon Feb 22, 2010 11:28 am 
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I have also seen this before. It's pretty amazing. Reflecting on my own 26 years of electrical work, I can recall some pretty unsafe habits that were quite common in the mid-80's but are rarely tolerated now. On many occaisions, I have seen people flick their finger across a 120V control circuit to see if its hot. Indeed, old habits die hard but, progress is being made.


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PostPosted: Mon Feb 22, 2010 12:14 pm 
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Other professions have already been through this evolution. Even knowing the risks, race car drivers and football players weren't particularly happy about having to wear PPE in the beginning either. Now no one can imagine an NFL player without his helmet of a race car diver without his crash helmet.

Arc flash PPE is hot and cumbersome, but is necessary due to the risks. The more we wear it, the more accepting we become of it.


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PostPosted: Mon Mar 01, 2010 7:41 am 
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I have worked with electricians in Egypt who tested whether fuses were blown on 400/230Y systems by touching the barrel with their bare hands to see if they were warm, indicating current flow.


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PostPosted: Mon Mar 01, 2010 12:01 pm 
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Zog wrote:
Came across this over the weekend. This is from the 1924 edition of the American Electricians Handbook.

115 - Electricians often test circuits for the presence of voltage by touching the conductors with the fingers. This method is safe where the voltage does not exceed 250V and is often very convenient for locating a blown out fuse or ascerting whether or not a circuit is alove. Some men can endure the electrical shock that results without discomfort wheras others cannot.

116 - The presence of low voltages can be determined by "tasting". This method is feasable only when the pressure is but a few volts and hence is only used in bell and signal work. When the voltage is low, the bared ends of the conductor constituting the two sides of the circuit are held a short distance apart on the tounge. If voltage is present, a peculiarly mild burning sensation results, which will never be forgotton after one experienced it. The "taste" is due to the electrolytic decomposition of the liquids on the tounge, which produces a salt having a taste.

Wow!

Why post this? Because this shows how far most of us have evolved. Some of the old timers may have actually done this, sometimes methods like this get passed down. Obviously these practices are very dangerous and would not be followed today with anyone educated in the effects of electricity on the human body, or with a drop of common sense.

There seems to be a lot of people that hate the new OSHA and NFPA 70E rules and are reluctant to follow them. Someday, someone will be posting something similar to this talking about back in the days when we were reckless and uneducated about arc flash hazards.

After all, there was a time when 2 guys in Italy were thought to be crazy becasue they thought the earth was round.


Yes, I have copy of this and use it in my Arc Flash Studies Training and Electrical Safety Training classes to illustrate how much we did not know back then and how the culture has changed. .... except there always seems to be 1 or 2 in every class that seems to have used this practice - to quote Zog....

"WOW!"

I have a copy from sometime in the 1940's where this was still an accepted practice.

We are changing again with arc flash and PPE. 10 years ago, arc flash was just an "unavoidable hazard" by many and NFPA, IEEE and other's have taken great strides to change the culture.

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PostPosted: Mon Mar 01, 2010 12:53 pm 
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30+ years ago I would use the finger/thumb to check to know if a new meter base/service was hot before plugging in the meter. The voltmeter was always on the truck.

But those were the days when I was sure I would live forever!


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PostPosted: Tue Mar 16, 2010 2:12 pm 
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History of electrical safety

This is in the 1940 version too.

Remember, in 1800, Alexander Volta, stuck two wires to his "battery" in his ears and claimed in his diary that "I received such a pain, that I shall never do that again". This wasn't that long ago!


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PostPosted: Sun Mar 21, 2010 5:10 pm 
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brainfiller wrote:
Yes, I have copy of this and use it in my Arc Flash Studies Training and Electrical Safety Training classes to illustrate how much we did not know back then and how the culture has changed. .... except there always seems to be 1 or 2 in every class that seems to have used this practice - to quote Zog....

"WOW!"

I have a copy from sometime in the 1940's where this was still an accepted practice.

We are changing again with arc flash and PPE. 10 years ago, arc flash was just an "unavoidable hazard" by many and NFPA, IEEE and other's have taken great strides to change the culture.


And here it is...... from the 1942 American Electrician's Handbook. You have to love the phrase in the description about "tasting" to determine the presence of low voltage "a peculiar mildly burning sensation resluts, which will never be forgotten after one has experienced it" I prefer to just read the meter. :eek:


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