Here's something you don't see every day:
Product: Fluke 8x V Series Digital Multimeters (DMM)
Hazard: Some products may have an intermittent electrical connection in the COM terminal which may cause an operator to incorrectly assess a hazardous electrical installation as being disconnected/safe to touch. </cite>
Not on their full-blown multimeters, but ISTR they've had several recalls on their circuit testers with attached probes like the current T150?
Made in China.
The problem usually is with anything you get made by third parties, one of quality control, particularly of hidden parts. Things like USB chargers that fall to bits leaving live terminals exposed, and the obvious removal of parts making power supplies RF noisy, cables that short at the join where the lead goes into the plug for changing laptops, which then catch fire. Exploding Lithium batteries due usually to naff manufacture or the charging circuit failing.
You certainly don't want safety gear to be in itself faulty. Back many moons ago, there was a batch of neon screwdrivers where due to the construction, a tiny finger of metal could short out the neon, putting the series resistor between your finger and the mains. Bit awkward if you might have touched something earthed at the same time. Brian
Although fluke did point out that you should be using a dedicated mains tester for proving dead, a multimeter isn't really for that.
I took a look at some of the other recalls on the list
Mothballs banned as carcinogenic, who knew? We spend half our chemistry lessons melting boiling tubes full of napthalene.
Seems like "vevor" brand power tools are probably worth a miss, I think I've seen a few youtubers reviewing/promoting them ...
Just another normal day in Amazon fake-brands land...
Although this one amused me:
Brand: Anker Model/type: Anker 535 Power Bank (PowerCore 20k) A1366 A manufacturing flaw may have caused potential defects in some of the power banks. The negative temperature coefficient thermistors (“NTCs”) may have been misplaced during the production process. This causes the NTC to press on and damage the battery cell, which can lead to overheating of the power bank and potentially cause a fire.
So the fire protection system caused it to catch fire. Oops.
Theo
Including the ethernet switch where live was wired to the metal case.
"It's got a website, it must be legit"
Andy Burns snipped-for-privacy@andyburns.uk wrote
Never did anything like that.
When I'm relying on a dead circuit I first test it to prove the tester, then turn it off, then test again.
I _could_ be unlucky and pick the moment when the tester died, but it's not likely.
Andy
You could be even more certain by retesting the tester on a still live circuit - but that is rather overkill.
There are 'proving units' designed to make enough voltage to cause a mains tester to detect them. Then you don't need mains to confirm correct operation. That's part of the standard proving dead procedure:
I presume the other factors that make a probe-style tester better suited than a multimeter for proving dead includes
simpler LED rather than numeric LCD display
non-detachable leads
less complication from range/function selection
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