I am looking to buy myself a Multimeter, not that I need one but it's
just something I want to learn to use, could come in handy some day! I
look after 2 fairly modern boilers so it could prove useful if one ever
develops a fault.
So my questions are, how hard is it to learn to use one? And are there
any which should be avoided?
Once another form at school (GCSE chemistry) were doing a practical
where they were coating keys etc in copper by electrolysis. The
instructions they followed were by a teacher without a clue how to
measure current. Cue 28 fuses needing replacement! I think they were the
ordinary glass type, but it still took a physics teacher and technician
ages to change them.
On Monday, August 27, 2012 11:13:47 PM UTC+1, Part timer wrote:
I've had that, last year I replaced something like 25 20mm 250ma fuses in our stock DMMs. £11
The problem is the lab sheet says mearure the current coming from the power suply so a lot of students connect the DMM in ameter mode across the PSU terminals, Obviously they don't get a shock, until I hit them for doing it ;-)
But my prefered cheap meter is....£18
This has an included thermocouple for measuring temerature.
1) don't these things have popup breakers rather than fuses?
2) Haven't these kids had a lesson before they get their mitts on the
kit? Doesn't Teacher go through where you'd measure current as opposed
"That excessive bail ought not to be required, nor excessive fines imposed,
On Tuesday, August 28, 2012 12:35:51 PM UTC+1, Andy Dingley wrote:
I don't think that's true, certainly the ones I've used aren't super fast in fact They might be more expensive becuase of supply and demand.
The fuses I've used to replace the ones in the 328 meter
are about 20p each
maybe the fluke branded ones are more expensive.
http://www.rapidonline.com/Electrical-Power/Quick-blow-20-x-5mm-glass-fuses-64564/?sid ¯81c141-6682-466d-88c1-644255f82c5f> maybe the fluke branded ones are more expensive.
My Maplin meter uses standard 20mm fast blow. But whether this protects
the meter as well as the Fluke type from a massive overload, who knows?
*Despite the cost of living, have you noticed how it remains so popular?*
Dave Plowman firstname.lastname@example.org London SW
On Tuesday, August 28, 2012 1:46:49 PM UTC+1, Dave Plowman (News) wrote:
True, I've had a total of 89, 318 & 328 over the last few years only 3 have gone
faulty so that's not too bad, not sure we'd have done better buying 90 odd
flukes we certainly found it easier to replace the cheap meters.
Looking at fuses
Not sure how much a geniuine fluke fuse would cost maybe adda zero on the end
Standard 20 mm fuses are only rated at 250 V with a breaking capacity of
35 A (glass type) or 1.5 kA for the ceramic HBC types.
The fuses fitted in multimeters with Cat III/IV safety ratings have much
higher voltage and breaking capacities. Taking the Fluke 77-4 meter as
an example, the 440 mA fuse is rated to break 10 kA at 1 kV and the 11 A
fuse for the highest current range will handle 20 kA at 1 kV.
If you use your multimeter in your consumer unit or with a big battery
bank, or anywhere else where high prospective short-circuit fault levels
are present, the cost of the correct fuses isn't much to pay to avoid
any risk of the test leads suddenly vapourising in front of your face.
Indeed. Regular readers may recall that report from the shopping mall
where a meter with inappropriate protection was used on a distribution
board... a mains transient caused a breakdown in the DVM which triggered
a major arc flash event - killing the operator and a bystander IIRC.
On Tuesday, August 28, 2012 12:21:00 PM UTC+1, Tim Streater wrote:
No. You're probbaly thinking of cutouts which are slow acting.
well sort of, most have had perhaps 10 years at school, most should have done physics to GSCE or A-Level before they even come to univ.
No. the teachers here are lecturers their job appears to be pointing at a whiteboard controlled from their labtop then telling them to printout a 100 power point slides.
Part of the idea of doing a practical lab is to learn stuff by experiment.
You;d have thought parent could teach their kids how to sit on stalls/chairs quietly and attentively while the teacher or lecturer speaks too.
what do you actually need to measure? If it's basic continuity etc
then a multifunction electrical tester will probably be cheaper, more
robust, and more reliable.
this sort of thing
That's made me think. All I really need is voltage & continuity.
Typical application, client removes loop in rose, joins all reds, all
blacks, loses sleeve on switch live. Quite common.
I find it a right PITA trying to hold two 'probes' and the DMM so I can
see it. You need three hands!
Something like that where the results are displayed on one of the
'probes' would be much easier.
Dave - The Medway Handyman www.medwayhandyman.co.uk
On Sat, 25 Aug 2012 10:12:33 +0100, The Medway Handyman wrote:
When I first got a MM I made up a 'probe' from a suitable plug, an insulated
pin clip and about 20' or so of nice flexible wire. It's greta for clipping
to a terminal and then I can wander off looking for t'other end of the
Very handy in France in a house with a mixture of French and English cabling
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