Screwdriver with neon electricity tester

[Lieutenant Scott]

[Lieutenant Scott]

Maybe you forgot to touch the metal bit on the handle?

If you'd have touched the two ends together like I do, you would have been in control of the wires and not be taken by surprise.

As long as you aren't up a ladder it'll just hurt. If you're up a ladder then things get broken.

[Lieutenant Scott]

They tend to have a sleeve almost to the tip of the screwdriver.

[Lieutenant Scott]

A road is different every time, different cars, different drivers. Electricity is much more predictable.

[Lieutenant Scott]

Maybe subconsciously, but not mathematically.

But you can't get into the sealed off shaft, so you cannot calculate.

[Tim Streater]

Thanks for agreeing with me.

Sure you can. You get your geology experts and your coal mine experts and any others that are pertinent. The coal mine may even say there aren't any just there. In any case you gather the information, and take a view as to the risk. That's still a calculation.

[Lieutenant Scott]

I'd hardly call what the subconscious does "calculating". It's more like an expert system on a computer from a couple of decades ago.

Most people don't go that far.

[John Rumm]

Most I have seen leave a good deal more than 4mm of blade exposed...

If working correctly, and at nominal mains voltage that is true, but that alone is not good enough. They would also need to remain safe even if compromised by internal condensation, and also in the presence of high transient voltages. Neither of which they can manage. The also don't incorporate finger guarding which is another fail.

[John Rumm]

I don't think you have really thought that through have you? Every electrical installation is different, as is every circuit, and possibly changes even with the time of day. When you start looking at behaviour under fault conditions, the nature of the supply, and the earthing arrangements take on a very significant influences.

Two factors have particular significance; the supply impedance, and the earth loop impedance. The normal ranges of acceptable values of these can mean the difference under fault conditions of between 20,000A. I hope you can appreciate that the latter will result in a significantly more damaging effects than the former.

Could I suggest you read this article which gives a fairly detailed breakdown of the events following the use of inappropriate test equipment on a supply with a low impedance (aka a "high energy" supply):

that in domestic environments in this country, it is possible to find supplies that have an impedance of over 0.50 ohms, and ones with less than 0.01 ohms. If you encounter one similar to the latter, there are significant implications.

[Tim Streater]

Wriggling again. Nice try.

Well they will if they're insurance assessors, now won't they?

[Lieutenant Scott]

That article shows that things can go severely wrong. But how many times do they not go wrong? Most of them! If we prevented every possibility, we'd all have nuclear fallout shelters in our gardens.

[Lieutenant Scott]

Nothing of the sort. When you cross the road and you "feel" that you have enough time to get across before the car reaches you, there are no measurements taken. You didn't work out the speed of the car, you didn't work out the distance from it to you, and you didn't observe the manufacturer and model of the car and look up its braking distance.

Mine didn't.

[The Medway Handyman]

I reckon someone miss heard "a degree of mental illness".

[Lieutenant Scott]

Oh do grow up.

[Tim Streater]

OK, bored now. Buh-bye.

[Lieutenant Scott]

It hurts when you're wrong doesn't it?

[brass monkey]

LMFAO, you should know.

[Tim Streater]

Except I wasn't, as you admitted or tried to wriggle out of. Piss off now, there's a good boy.

[ARWadsworth]

He has spent too much time with his parrots. He now just keeps on repeating himself.

[Clive George]

If you're going to ignore somebody, do it properly. Declaring a conversation over, bidding farewell, then carrying on less than 30 minutes later shows a remarkable lack of self-control.

The guy's a numpty, everybody knows that, you gain nothing by discussing with him. But it's up to you to stop - he won't.