Interesting Tool

19 years ago

I recently became aware of a tool called "Voltage Alert" made by Fluke. It is a battery operated large pencil like tool, with an insulated tip, that can be used to sense the presence of AC voltage. If you hold the tip in close proximity of something energized with AC line voltage, the tip will light up and an alarm will sound. It can be used to check an electrical outlet or the wire plugged into it without touching a live bear wire. You can also check to see if an appliance is properly grounded with this tester. I put mine to good use when I was at a neighborÂs house to check her new microwave oven for proper grounding. That oven was fine. However, when I brought the tip of the tester within 6 inches of her wall mounted conventional electric oven, the tip lit up and the alarm sounded. A further check with a voltmeter showed there was 120v AC on the frame of the oven with respect to her stainless steel sink. The oven was working fine since it was installed 7 years ago. I called the company that installed the oven to tell them it had to be wired incorrectly. At first they said that was impossible, but when I told them I could light a 100 watt bulb by connecting a wire from the oven hinge to the center of the bulb while holding the outside threads on the kitchen sink, the began to believe me. Finally, they sent out the person who installed it 7 years ago. We pulled the oven out of the wall to see how it was connected to the three-wire 240v service. They had connected the green frame ground wire from the oven to the hot red wire instead of the white neutral wire. This connected the oven frame directly to a 120v 45-amp source. This simple test may have saved a life. If the 85-year-old widow got between the oven frame and a metal outlet cover or the kitchen sink, it would have looked like she had a heart attack.

Sears sells their version of this voltage sensor for $10.00. The Fluke one I have (Model 1 AC-A II) costs $25.00, which is also sold by Sears. I liked the Fluke one better because it has a wider test voltage range of 90 to 1000 volts, and it has a self-test feature to make sure the battery is working OK. The flat tip is also thinner, so it fits in the slot of a wall outlet with narrow openings, where the Sears version was too fat for some outlets.

Charles Ranheim

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Comments (5)

mikie_gw
19 years ago
I just lick my fingers on one hand and touch the back side of my other hand ,,, after removing one shoe. You can tell which way ac flows best that way.
Saves needing to carry around a tester. Sometimes I feed strange holding the helpers hand though when my arms arent long enuff.
cranheim
Original Author
19 years ago
Mikie,
I worked for IBM for 40 years before retirement installing and serviceing mainframe computers. If I used your method, I would have been killed many times over. They did not have this simple voltage probe back then. I had to rely on meters and scopes to identify power problems. This is such a simple cheap tool that fits in your shirt pocket like a pen. I worked with an electrician at my daughter's house on a backup generator system. He said they all carry one of these sensors because it so easy to carry and use for basic tests. Good luck with your test procedures. Charles Ranheim
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quincy
19 years ago
If you ask me, everyone that should ever come into contact with AC should go and get one of these. I got one free with a new multimeter a couple of years ago and I use the voltalert all the time. Before I even touch a faulty machine, I get out my little fluke pen and just scan it around against the chassis and even, after removing power to a machine, will use it to verify power is off. It is an incredibly versatile little non contact tool. Makes fault finding a bit easier. I'm with you Charles, a handy tool. I have one in my pocket right now as I type this...
My dad used to lick his fingers and slap the wires too in the 'good ol days' but I think we all know how clever that method is...
newjerseybt
19 years ago
"I worked for IBM for 40 years before retirement installing and serviceing mainframe computers."
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Must have been the days of the IBM 360-370. I used to be a Assembler programmer. One of the most complicated machines ever created back then. Punch tape was used for carriage control. Real ferrite "cores" for storage. lol
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I remember the old tube radios. Many had a dangerous electrical problem. Depending on which way you put the non-polarized plug in the receptacle, put you at risk for electrocution.

If a grandmother lifted her AM radio to clean under it with one hand touching the chassis screws underneath the radio and then sponged the faucet, death could occur as the chassis may be "hot". If you reversed the plug in the wall, you would be safe. I believe later models isolated the chassis with a 47K resistor and a small bypass cap.
cranheim
Original Author
19 years ago
By the time the 360/370 systems came out, I had already gone through the relay controlled tabulators, tube computors (Thousands of tubes), then the solid state 360, 370, 7000, and 3090 systems. The tube machines were the most dangerous. You could easily get between 400v of regulated DC, not to mention the normal 240 3phase power. I learned early on to respect electric power. It would have been nice to have on of these VoltAlert probes in those days. As safety conscious as IBM was, we did lose some people on the assembly line as well in the field due to electric shock. This is why I thought it might be useful to mention this simple inexpensive tool that might save soneone from getting a shock as well as making problem determine easier. Just my opinion. Take care, Charles Ranheim