Multimeter fuses

My multimeter has stopped measuring things on the 200mA current range. Turns out the fuse is blown. It's a chunky 1A ultra fast acting ceramic number - size is 10x35mm. I had a look around and the cheapest is about 7 quid. This is rather galling because these fuses are easy to blow... one slip with the meter probes onto a voltage line and the fuse is toast.

Normal 20mm quick blow fuses are about 20p, and looking at the spec there doesn't seem to be much difference in terms of blow times. I could always derate - eg use 500mA instead of 1A. The 'official' fuses are 600Vac and the cheap ones 250Vac... but I'm hardly likely to be using them on 3-phase. So anyone see any problems with substituting a cheap fuse? Or have a cheaper source of the 'official' fuses?

Cheers, Theo

Reply to
Theo Markettos
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Likely the original is a High Rupture Current variety meant to safely open even with a the surge of shorted low impedance mains, a cheaper fuse may not open fast enough or might just weld or fail in in non passive manner...

This article changed my view of multimeters for ever:

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high voltage, >50V a test stick , not a neon `mains tester` or a multimeter with Fluke written on it with fused test leads.

Have a pile of cheap meters that are great for low voltage use only.

Cheers Adam

Reply to
Adam Aglionby

Well, yes. The meter in current mode presents near enough a dead short, hence the fuse.

My Fluke does its best by reading 'leads' when you swap from current to voltage. But I've still managed to blow their V expensive fuse.

Cheaper meters do use standard fuses. Not sure if in practice this would make it more likely to damage one which uses the expensive kind. But it might be an expensive try out.

Reply to
Dave Plowman (News)

Thanks, these look more sensibly priced:

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Reply to
Theo Markettos

Being pedantic, Low Voltage is 50v to 1000v AC, Extra Low Voltage is below 50v AC, and High is above 1000v.

Reply to
A.Lee

Available at good electrical distributors/wholesalers/shops. Had to fit one last week to an extractor fan that said "Must be protected by a 1A fuse"

Reply to
A.Lee

Thanks for that. I'd not have considered that putting a zillion amps through a fuse would cause it to fail in anything other than open circuit, but high voltages and currents can do strange things (ionisation, vapourisation, etc).

This one /does/ have Fluke written on it. Not that I take it near high voltage, but I suppose there's a risk that somebody else might.

Theo

Reply to
Theo Markettos

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