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Author Topic: 3-light tester RPBG upgrade  (Read 24819 times)

frank kayser

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Re: 3-light tester RPBG upgrade
« Reply #80 on: March 06, 2015, 11:35:26 AM »

The dangers of an active mind, idle time, and a house full of randomly wired outlets. Oh my!  ;)
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Stephen Swaffer

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Re: 3-light tester RPBG upgrade
« Reply #81 on: March 06, 2015, 08:41:32 PM »


So, why did they fall out of favor and common use? Anything in code that makes them a violation to use? Have there been any deaths or injuries due to their use? Remember, this is about as simple as you can get, a neon bulb and a resistor connected to the screwdriver blade on one end and the brass touch button on the butt of the handle.


So the only thing relating to this I can find in NFPA 70E is that if there is a risk of entering the "restricted approach boundary" the PPE for shock protection must be worn. "Restricted approach" for less than 150 vac is "avoid contact".  I suppose that one could argue that there would be a risk of touching the screwdriver blade/shaft so insulating gloves would be required-which would defeat the touchpad.  A plug in tester similar to the 3 light tester would not share that risk-so as long as it could be shown that no shock hazard exists (UL listing??) from the touch pad then it should be acceptable.
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Mike Sokol

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Re: 3-light tester RPBG upgrade
« Reply #82 on: March 06, 2015, 08:47:37 PM »

I suppose that one could argue that there would be a risk of touching the screwdriver blade/shaft so insulating gloves would be required-which would defeat the touchpad.  A plug in tester similar to the 3 light tester would not share that risk-so as long as it could be shown that no shock hazard exists (UL listing??) from the touch pad then it should be acceptable.

My $2 neon screwdriver voltage tester has a clear plastic insulating sleeve over most of the shaft, with only the flat tip metal exposed. So not really dangerous unless the neon bulb and resistor both short out at the same time. There's just not much that can wrong with the KISS design.
« Last Edit: March 07, 2015, 09:11:09 AM by Mike Sokol »
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Mike Sokol
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Stephen Swaffer

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Re: 3-light tester RPBG upgrade
« Reply #83 on: March 06, 2015, 09:19:01 PM »

Here is some interesting technical info on neon lamps.  I didn't know there were so many options-different colors and even high brightness. Even the high brightness have a 20,000 hour average life-that a long time to hold a test screwdriver in a receptacle!

http://www.intl-lighttech.com/products/light-sources/lamps/neon
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Mike Sokol

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Re: 3-light tester RPBG upgrade
« Reply #84 on: March 06, 2015, 09:36:14 PM »

Here is some interesting technical info on neon lamps.  I didn't know there were so many options-different colors and even high brightness. Even the high brightness have a 20,000 hour average life-that a long time to hold a test screwdriver in a receptacle!

http://www.intl-lighttech.com/products/light-sources/lamps/neon

Cool....

And they used to use neon bulbs for logic elements. Here's a neon bulb logic circuit driving Nixie tubes, which are also neon.

http://wwwhome.cs.utwente.nl/~ptdeboer/ham/neonclock/
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Mike Sokol
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John Roberts {JR}

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Re: 3-light tester RPBG upgrade
« Reply #85 on: March 06, 2015, 10:18:32 PM »

I vaguely recall my (older) brother building a gadget back when he was in HS. He called it a "foo counter" and it was a bunch of components with resistors, caps and neon lamps, that would randomly blink on and off.

Thinking about it now, I suspect it was a large voltage DC supply (perhaps the line rectified) with resistors charging up caps. The caps also had neon lamps in parallel across them. When the caps charged up high enough voltage to break down the neon gas the lamp would flash and discharge the cap. The randomness of threshold voltages, cap values etc, resulted in random blinky lights. As my brother described it to me "foo"s were invisible rays from outer space and the lights would flash every time one passed through the device.

I knew it was a joke but never bothered to figure out how it works (or I think it worked) until now.

JR
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Mike Sokol

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Re: 3-light tester RPBG upgrade
« Reply #86 on: March 07, 2015, 12:53:13 AM »

I vaguely recall my (older) brother building a gadget back when he was in HS. He called it a "foo counter" and it was a bunch of components with resistors, caps and neon lamps, that would randomly blink on and off.

Sort of like this? https://www.youtube.com/watch?v=lph5zAdcwi8
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Mike Sokol
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John Roberts {JR}

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Re: 3-light tester RPBG upgrade
« Reply #87 on: March 07, 2015, 10:04:45 AM »

Sort of like this? https://www.youtube.com/watch?v=lph5zAdcwi8

As I recall not as many lights on steady... mostly off but random short flashes on... but this was more than 50 years ago so my memory is not perfect.   

======

I got my parts in today so now I have some neon bulbs to play with.


JR
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gordonmcgregor

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Re: 3-light tester RPBG upgrade
« Reply #88 on: March 20, 2015, 05:50:01 PM »

Mike et al okay I live in 240V world but those little neon screwdrivers were banned from my work place a good while ago for 2 reasons 1) it was possible to get a shock if they were wet,or if the insulation got cracked, I personally got stung by the thing being damp and I tell you it hurt :'(. The other reason was a general ban on single pole testers because guys were putting the thing into the live contact if it didn't light then the circuit is dead right? eh no not when the neuutral or ground are live hence the insistance on 2 pole connectors.
We use this thing http://www.socketandsee.co.uk/details.asp?categoryid=197&ProductID=11&Product=Socket & See PDL234 Plus Part P Loop Testing Kit  nowadays, and though it won't directly show a hot ground it will refuse to do a loop test which warns you of ground issue that you can then check with a meter.
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Stephen Swaffer

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Re: 3-light tester RPBG upgrade
« Reply #89 on: March 22, 2015, 03:22:19 PM »

Mike et al okay I live in 240V world but those little neon screwdrivers were banned from my work place a good while ago for 2 reasons 1) it was possible to get a shock if they were wet,or if the insulation got cracked, I personally got stung by the thing being damp and I tell you it hurt :'(. The other reason was a general ban on single pole testers because guys were putting the thing into the live contact if it didn't light then the circuit is dead right?

And neither of this is the fault of the tool.  No matter the simplicity or complexity of your tool of choice there are 2 very important prerequisites to using it.

First, you must understand how to correctly use it-this includes knowing the safety hazards involved.

Second, you must understand its limitations.

The limitation of the complex tester you mentioned is essentially (if I understand correctly) the same limitation if the 3 light tester not being able to discern a RPBG.

No tool is foolproof (guess what happens if you use a damp DMM probe in a receptacle?)-and as this discussion shows, the less user knowledge the tool design demands, the more difficult it is to design and the more complex the design.  The more complex the design, the more likely it is to fail at some point.

With a thorough understanding, it is possible to make all of the tests necessary to verify a receptacle with a DMM (you can usually even use your body as a ground and discern a RPBG.  The 3 light tester along side the neon screwdriver is a more convenient tool.

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Steve Swaffer

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Re: 3-light tester RPBG upgrade
« Reply #89 on: March 22, 2015, 03:22:19 PM »


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