Meter Probe

[Peter BellParticipant @peterbell11509]

I'm running short of simple meter probes, eveything I look at is either expensive rubbish or not what I want.

This is what I've previously used, plugs onto a bannana plug lead (4mm?) so I can change it for a croc clip.

Does anyone recogise them and know if anything similar is still available?

Thanks Peter

[Peter BellParticipant @peterbell11509]

[Grindstone CowboyParticipant @grindstonecowboy]

CPC do a selection which may be suitable – see here

[Don CoxParticipant @doncox80133]

I'm pretty sure those were the ones which came with most B.T. test gear when I last worked for them, now 23 years ago. In all that time I've never been able to track down a source of supply for replacements and I too have had to buy sub standard flimsy stuff. I'll be interested to see what else comes up.

Don

[Nick Clarke 3Participant @nickclarke3]

If you are looking for ex GPO what about the Rugby Radio Rally this Sunday at Princethorpe College?

[peak4Participant @peak4]

Certainly the same as Post Office Telephones/BT as they are exactly the same as the ones I use.

I've been looking for a few myself.

Bill

[Peter BellParticipant @peterbell11509]

Yes looks like they are GPO/BT and we all want some!

Think I bought a box of them at the Telford rally some time ago. Cannot find the box which would have the part no on them.

Peter

[DiogenesParticipant @diogenes]

..this kind of thing?

https://uk.rs-online.com/web/p/multimeter-test-leads/1247406/

[Robert Atkinson 2Participant @robertatkinson2]

The old BT leads were only designed for low voltage use. You should really only use leads and probes with sleeved safety plugs. Buy them from a reptutable supplier like RS Farnel, CPC or electrical factor. If you are a business or employer of any sort you must use appropriate safety leads. For domestic mains on the "user" side of the socket they should be "CAT II" at least andfor house wiring work CAT III see http://www.hse.gov.uk/pUbns/priced/gs38.pdf

Robert G8RPI.

[Don CoxParticipant @doncox80133]

Over the 33 years I worked for PO/BT I had pretty much daily contact with their multi-meters, both as an exchange maintainer and as a linesman. Over that time the test gear was updated and the test leads too. One of the more annoying "improvements" was to the test leads which joined the probes, pictured above in the original posting, to the meter. Later ones of these had spring loaded insulating shrouds which covered the bare metal lead ends if they weren't plugged in. These had the very annoying effect of forcing the probes off of the end of the meter leads at the crucial moment. The need to get the probe onto a soldered tag deep inside a switch was difficult enough without the thing coming away in your hand just as you were going to look at the meter.

The latest standard test leads are next to useless in those type of circumstances, so the message must be look after any of this kit you still have, there ain't going to be anymore.

Don

[Mike PooleParticipant @mikepoole82104]

Testing has become increasingly difficult as the requirements for shrouding have become more onerous. Needle points are useful for checks on PCBs that have been lacquered, they can also be useful for piercing the insulation on cable, obviously this must only be used where the pinhole left will not compromise the safety and integrity of the installation and personnel. Sometimes you can have fond memories of slate backplanes and rigid bare interconnections, accessibility was easy but so was an accidental touch when live testing.

Mike

[Neil WyattModerator @neilwyatt]

Even my cheapest £5 'disposable' multimeter has shrouded plugs. Sobering that it is an order of magnitude + more accurate than my expensive old moving coil meters.

My better meter has shrouded plugs and only the very tips are bare – I find this style much easier to use TBH.

Neil

[Peter BellParticipant @peterbell11509]

Yes spring loaded shrouds were really annoying with leads popping off all the time. Also had bad experiences with lower priced meters belonging to others, the meters work fine but the leads just dont last.

Sorted for now but its opened my eyes to whats available for the future so thanks everyone.

Peter

[John HaineParticipant @johnhaine32865]

Posted by Neil Wyatt on 13/08/2019 20:57:53:

Even my cheapest £5 'disposable' multimeter has shrouded plugs. Sobering that it is an order of magnitude + more accurate than my expensive old moving coil meters.

My better meter has shrouded plugs and only the very tips are bare – I find this style much easier to use TBH.

Neil

Or at least precise?

[Robert Atkinson 2Participant @robertatkinson2]

The 4mm plugs with spring loaded sleeves are pretty useless and no longer common (or acceptable for new mains rated leads).

When teaching use of meters I had a "lesson" on digital accuracy. It involved a PP3 battery, AVO Model 8 analog meter (1%) and AVO DA116 digital meter (0.5% +1 count). Tne lesson was to measure the battery with both meters and discuss the results. The Model 8 read around 8.4V and the DA116 read 9.0V. Most students said the Model 8 was out of calibration and inaccurate (dispite having a in cal sticker) by 0.6V. A small percentage said the DA116 was faulty. – these had noticed that the PP3 was a rechargable with a nominal voltage of 8.4V. The DA116 had been deliberately adjusted to over-read. More digits does not mean more accuracy. The DA116 was only good to +_ 0.055V making the last digit virtually useless.

Robert G8RPI.

[Peter BellParticipant @peterbell11509]

All interesting stuff.

I find I quite like using my Avo 8 occasionally especially if I'm reading current, I find it far easier to follow a swaying needle rather than rolling digits and of course it doesnt power off after a few minutes.

Peter G4LSA

[Neil WyattModerator @neilwyatt]

Posted by John Haine on 14/08/2019 08:55:26:

Posted by Neil Wyatt on 13/08/2019 20:57:53:

Even my cheapest £5 'disposable' multimeter has shrouded plugs. Sobering that it is an order of magnitude + more accurate than my expensive old moving coil meters.

My better meter has shrouded plugs and only the very tips are bare – I find this style much easier to use TBH.

Neil

Or at least precise?

No, very much more accurate, at least if the agreement of multiple meters on a reading and the occasional test against an accurate reference voltage is sufficient test. Essentially, it isn't any more expensive to make them accurate to within a few tenths of a percent, so there's no incentive to make them less accurate.

Neil

[Dave HalfordParticipant @davehalford22513]

Posted by Don Cox on 13/08/2019 09:42:35:

Later ones of these had spring loaded insulating shrouds which covered the bare metal lead ends if they weren't plugged in. These had the very annoying effect of forcing the probes off of the end of the meter leads at the crucial moment. The need to get the probe onto a soldered tag deep inside a switch was difficult enough without the thing coming away in your hand just as you were going to look at the meter.

The latest standard test leads are next to useless in those type of circumstances, so the message must be look after any of this kit you still have, there ain't going to be anymore.

Don

Still got mine and they still push the probes off

[Mike PooleParticipant @mikepoole82104]

E-Z Hooks were one of my favourite small probes for bench repair work E-Z Hooks

Mike

[Anthony KendallParticipant @anthonykendall53479]

Posted by Peter Bell on 14/08/2019 12:36:37:

All interesting stuff.I find I quite like using my Avo 8 occasionally especially if I'm reading current, I find it far easier to follow a swaying needle rather than rolling digits and of course it doesnt power off after a few minutes. Peter G4LSA

Peter – me too. I know exactly what you mean. I use digital about 95% of the time.
I find there are times when either has an advantage. Robert Atkinson's post was very interesting. The younger might be much more at home with digital, whereas the older are more at home with an Avo? I liken it to using a word processor – I can see errors much better if I print out – and I think that's an age thing!

It is amazing, though, what functionality and accuracy you can get from a 25 quid digital multimeter. Very good value, whatever leads you put on it.

[Robert Atkinson 2Participant @robertatkinson2]

Posted by Neil Wyatt on 14/08/2019 16:13:24:

Posted by John Haine on 14/08/2019 08:55:26:

Posted by Neil Wyatt on 13/08/2019 20:57:53:

Even my cheapest £5 'disposable' multimeter has shrouded plugs. Sobering that it is an order of magnitude + more accurate than my expensive old moving coil meters.

My better meter has shrouded plugs and only the very tips are bare – I find this style much easier to use TBH.

Neil

Or at least precise?

No, very much more accurate, at least if the agreement of multiple meters on a reading and the occasional test against an accurate reference voltage is sufficient test. Essentially, it isn't any more expensive to make them accurate to within a few tenths of a percent, so there's no incentive to make them less accurate.

Neil

Hi Neil,

I doubt any cheap meter is an order of magnitude more accurate than an expensive anlogue meter. A classical analogue meter like an AVO 8 has a specificed accuracy of 1% on DC volts. Even a good 31/2 digit DMM e.g. Fluke 110 series is only specified to 0.7 percent. plus 2 counts. Any 31/2 digit meter (1999 count) has only 0.05% resolution so with the best uncertanty of 1 count even if everything else is perfect they can only make 0.1% of full scale. Accuracy for AC, current and resistance is poorer. A single point check is not confirmation of overall accuracy.
Accuracy, precision, resolution and linearity all need to be considered. A great book on the subject is "Calibration Philosophy in practice" by Fluke.
I'm a bit of a ""volt-nut" I have meters up to 81/2 digit resolution, good solid state voltage references, Kelvin-Varley dividers etc.

Robert G8RPI.

Edited By Robert Atkinson 2 on 16/08/2019 11:11:09

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