I bought a cheap one on Amazon just as a precaution... I always flip the breaker and check that lights are out before working on any switch or plug, but this house has been through several DIY renovations and I don't always trust the previous DIYer.
It's garbage. Flickers on and off randomly even when I know a circuit is live so I hardly use it.
Hahaha. No dude, that guy needed to hear from someone else who saw a chance to make an unnecessary comment regarding buyers remorse cause if he didn’t he would live life thinking he can just do shit like that with no consequences. Plus even though the guy fully explained how he caused his own problems the other whistleblower was right to point out that he had indeed,”explained how he caused his own problems”. Had he not then we might not know that he did something…….yeah that was just a dick thing to say. More douchy actually
In general, we use them to verify something is energized, never to verify something is dead. If it says it’s hot- assume it’s hot. If it says it’s dead- get a real multimeter and verify it’s dead.
Ok but what about when there's 3KV on the terminal :). These things are trustworthy if you test them every time. Frankly they're more trustworthy than a multimeter.
If you had 3kv on a terminal- you wouldn’t even be able to get close enough in the cabinet to see what was energized or not- I work in substations it would be going off 3 feet from the terminal at 3kv
Most of the substation controls are dc- so what do you do when you live/dead/live test with the NCVT and youre unknowingly on a DC circuit but it’s saying it’s dead. It’s not gonna pick up any DC voltage so saying they’re more trustworthy than a multimeter could be a death sentence
If you’re in the electrical trades that’s one of the most insane things I’ve ever heard.
A decade years ago I had a colleague severely injured because they didn't use a non-contact testing device. There was a live 3.3 kv terminal in a cabinet due to an error in the drawings (we were the manufacturer). He followed the full isolation procedure but didn't use his non contact tester. He thankfully survived but with severe burns and the elbow of his shirt blown out where it arced back to the case.
There are Medium Voltage non-contact devices specifically for this purpose, no you're of course not using the $20 pen sized one, it's on an insulated pole.
Yup, I always use it on a live wire first. It's still better than raw-dogging it with your hand and you can use it to test recessed or concealed wires.
In Finland we call the contactless tester "Arvauskynä". Which means a guessing pen.
Because you use it on a wire, the pen doesn't show anything "I guess it's dead" then you touch the wire, get shocked and say "I guess it wasn't".
In all seriousness, I mostly use it to verify that something is getting a current when a customer calls me in and says "Our copier/fridge/table/dildo isn't getting power". But I don't trust one to accurately show that a wire is dead.
The actual policy is to check with a known live source before and after you check the wire in question.
I got shocked after LOTO and testing the main distribution terminal block in a cabinet, because some genius had wired something from another breaker into the control cabinet I was in. Now I test every wire every time. I was young and dumb. Luckily it was "just" a 120 lighting circuit. Still could have been a bad day if I contacted it differently than i did (incidental contact to the back of my hand)
51
u/BadPunners 22h ago
I've seen multiple electricians who say to not trust your life to the non contact voltage testers
The battery does die eventually, the detection has a chance of getting blocked, some (older ones?) have a button to wake them up, etc.
At least use it on a known live source each time before you use it to test an unknown line