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I've always relied on neon screwdrivers over the years and personally haven't had any issues with them. I recently bought a new one, but find that this lights up at the slightest hint of electricity (even touching it at both ends!) which I believe is a common problem with these devices. I don't want to put my trust in having to interpret the lamp's brightness as an indication of current.

I was wondering what the alternatives are. There are a lot of "non contact" pen-style testers on Amazon, but the reviews suggest that these are just as bad as neon screwdrivers for false positives. Any other suggestions?

Edit just to clarify, an example scenario would be testing the screw terminals inside a bathroom fan to identify the live and switched live. I'm assuming a non contact pen would be unsuitable due to the close proximity of the screw terminals?

Andrew Stephens
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  • I have been using this for many years, and found it good: https://www.amazon.co.uk/winner-smalltester13a-Mains-Tester-Socket-White/dp/B007JIRFYU – tlfong01 Mar 13 '22 at 09:39
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    @tlfong01 thanks but ideally looking for something that I can touch wires and screw terminals with. – Andrew Stephens Mar 13 '22 at 11:14
  • Or try this: Using A Voltage Detector - Around The Home, 54.1K subscribers, 67,623 views, 2016nov30 https://www.youtube.com/watch?v=LtY7T0frQUc – tlfong01 Mar 13 '22 at 11:36
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    Terminology correction: those neon testers (and all similar contact or non-contact devices) do not detect *current*, they detect *voltage*. There is often *voltage* present while there is no *current* flowing, so if you do end up with an actual *current* detector you could be in for a painful surprise... – brhans Mar 13 '22 at 14:20
  • Neon testers cannot light up simply from you holding it in your hands, unless you are Nikola Tesla. Or Magneto. It sounds like you were expecting a neon tester, but actually got a battery operated junk-heap. It is very hard to go wrong with a simple 3-light tester, which is 3 neon testers in one assembly, but the label is dangerously misleading (it is designed for wiring *errors* in new work, not wiring *failures* in old work). [More accurate label here](https://i.stack.imgur.com/ZkajL.png). – Harper - Reinstate Monica Mar 14 '22 at 04:26
  • @harper it's a neon tester (actually led) but definitely no battery in there. My daughter had something similar in a "science set" a few years ago - a clear tube with metal ends, and all that was inside was a resistor and led that would light up when you touched both ends. – Andrew Stephens Mar 14 '22 at 10:38
  • Well, either it's neon or LED. They are completely different technologies, and you can't realistically expect them to have similar behaviors. The characteristics of neon is what make those testers great, and they are still readily available, and since you are familiar with *that* tool, you should accept no substitute. – Harper - Reinstate Monica Mar 14 '22 at 18:15

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The solution is using a multi tester with two pins or a professional pin tester (try google Fluke).
I personally only use neon screwdrivers and those plastic fingered field detectors to stay safe. As most of my clientele is operational caterers who are complete and utter baboons when they work, I have to protect myself from kitchen personnel running to the fuse board and flipping the fuse of whatever it is I'm working on. Those field detectors beep when there is a current, so before I cut the fuse, I jab one such device in the line somewhere and just leave it there. When it starts beeping, it means they're at it again. It's a life saver.

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    If you're working in a place with "personnel", you *seriously* need Lockout/Tagout. They make [screw-on wedges](https://www.google.com/search?q=breaker+handle+lock&client=safari&rls=en&source=lnms&tbm=shop&sa=X&ved=2ahUKEwi-mpbhnMb2AhWBl2oFHdkTBFQQ_AUoAXoECAEQAw&biw=1040&bih=969&dpr=1) which hold the breaker off (starting at US$3) and have an attachment point for a tag. A developed country's employment laws probably make this *mandatory*. – Harper - Reinstate Monica Mar 14 '22 at 18:33
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That is an LED-based tester in a screwdriver form-factor (shape and structure).

You are making an error in labeling: confusing the form-factor with the operational technology. That is, you are using the word "neon tester" to describe all testers which look like a screwdriver. Don't do that. If you are describing the shape, use words to that effect: "screwdriver tester".

The problems with LED testers are exactly as you point out: not a reliable indicator. The characteristics of neon make it suitable for using it as you have.

Rather than learn a new tool, you should hold out for an actual neon tester of the kind you are familiar with. They remain available, but clearly the buyer must beware, since LED types are creeping in.

Harper - Reinstate Monica
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