electric shock from a cold water tap

Indeed, I was sick of the stupidity on some sites. Safety was fine, but as sites got safer, some things, PPE in particular actually became a risk. Trying to get a risk assessment passed to remove safety glasses or Hi Vis overtrousers was impossible, even if the control room was safer than the site office. So you sat there sweating, trying to see through your own glasses plus safety glasses and of course the icing on the cake was trying to operate a HMI wearing gloves. Something the full time site personnel didn't have the pleasure of.

Oddly enough I made two errors with two wire testers, neons have their foibles and No way would I put myself in a position where one would have the remote chance to be included in an accident report. But I normally used a DMM, a departure seemed a good idea as there is no easy place to find a return in cabinets now. I was a one hand type, and even now try to keep one hand in my pocket when switching the toaster on :-).

Anyway, I went for a Fluke light up device, two wires to prod onto the connectors and discrete lights about ten or twenty V apart.

First error was finding it was as sensitive as a neon almost! An o/c had me looking for the Voltage source!

Second one was reading 100V ac on a transformer and assuming it was fine.

It was wrongly terminated and 55V lit up the 100V LED but the 120V was out as I expected anyway.

There is always a problem with measuring anything, the test equipment often needs interpreting. I started out with an AVO 7 which needed a bit of understanding at 500 Ohms per Volt. Electricians would be O/K but trying to measure the anode Voltage on a triode was not easy.

But it leads one to question everything.

Much later I found that the Avo along with many of the now obsolete moving coil meters were far better for measuring in the region of kV. They took less current than the 10 Meg modern electronic devices and nobody generating 4kV produces more mA than the minimum for the job.

Yes, I had one. The only time I used it was at Rolls Royce. It was their procedure that phase rotation was tested early in commissioning.

You do get a bit spoiled with drives though.

We bought in a Chinese plate press once and fired it up in our works. The noise and damage was quite bad when the bomb doors opened the wrong way.

I carried a phase tester to commission that project, but with a large number of pumps connected to the same supply it never came out of the box.

Strange, but the early stuff seems odd now! The day when a colleague plunged a factory into darkness by simply doing an instant start/ run operation.

Programming a drive can be a pain, but when I think of the fun with DOL motors, I think trying to fathom a new suppliers "drivespeak" is easier, and less costly in fuses :-)

Rural location?

Is a water pump being activated when you open the tap?

Either way, your tap's route to earth is interrupted.

As someone above pointed out, there are at least 2 problems here.

Yea bonded metalwork is to reduce shock risk if all metalwork potential rises. It doesn't eliminate it. It greatly reduces the shock risk from hand to hand. Neutral failure would be an example. Now plug in something out in the garden, and there is shock risk from that to the wet ground. Bare feet on tiles in the house may perceive a potential when a hand is on a live tap. If a phase tester lights when on a tap, it is an indicator that something is wrong, regardless of how good or bad they are as test equipment.

Obviously just examples there. Nothing much is known about the circumstances here.