Problem with New Multimeter Test Leads - Page 1
Forum section: electronics / general

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 09, 2022, 02:47:43 pm
content: Hello. I have replaced stock multimeter test leads with generic ones that have silicone cords. The problem is that they don't fully plug in as you will notice in the video where I attempt to force in red plug to be able to get continuity:https://streamable.com/3u1knxThe old ones have plugs with the length of 2.8cm and the new ones are 3.5cm:I also don't understand why upon shaking test leads I get sudden readings that spike and drop back to zero. Is it due to bad connection or they are faulty?https://streamable.com/u9k3i6How would I go about cutting plugs' sleeves around conductors to make sure they fit properly and stay in place without overdoing it? Which delicate tool should I use to cut them?

author: coppice
author_rank: Super Contributor
timestamp: November 09, 2022, 03:00:56 pm
content: Test leads with shrouded 4mm plugs are not built to a formal standard. The sizes used to be all over the place, and you generally had to use the leads from the equipment manufacturer. Equipment and leads made in the last few years have pretty much settled on compatible measurements, so the compatibility problems have mostly gone away for anything new. There is still some funky stuff, like plugs which do not have a plastic tip on the pin, so you can still touch it when the plug is out. There are also plugs with a retracting shroud, so if the shroud won't fit down the hole it just gets pushed back. Those often fail to completely shroud the metal when inserted.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: November 09, 2022, 03:49:31 pm
content: Yes, I got some generic multimeter leads one time that had shrouds too long to fit in my meter. I just used a knife to trim the shrouds shorter, by slicing circumferentially. Didn't measure, just trial and error - cut a bit, check, cut a bit more.

author: EPAIII
author_rank: Super Contributor
timestamp: November 13, 2022, 06:40:43 am
content: There are good quality, replacement test leads available. Here's one source.https://probemaster.com/8000-series-test-leads-only/I am selling refurbished meters and was so impressed with the Probe Master leads that I am supplying them with each meter that I sell. I also use them on my own meters. I am not an employee of Probe Master nor have any connection to them other than as a customer.I am sure there are other quality brands of replacement test leads available.

author: VK3DRB
author_rank: Super Contributor
timestamp: November 13, 2022, 11:34:59 pm
content: Quote from: EPAIII on November 13, 2022, 06:40:43 amThey are good except for two things... they have protective shrouds and cannot be piggybacked. A pain in the arse. Pomona, Fluke and HCK leads have those blasted shrouds on them. On some older equipment, the shrouds get in the way so you cannot plug them in. And I cannot piggyback leads. When I get around to it, I will 3D print an adapter to allow paralleling of leads and let shrouded leads to connect to old equipment.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 15, 2022, 06:46:34 pm
content: I cut a bit of sleeve of red probe's plug and it did not make a difference. It seems that multimeter's port for red probe is narrower after I tried to plug black probe in it. With new probe leads the readings in V- ranges are still slightly chaotic in "200m" and "2" spectrums when I move and moreso shake probe leads in a contrast to older probe leads. With the older ones multimeter still shows sensing activity ("-" sign) but readings are not as chaotic as instead bump slightly. I wonder why that happens and why it can be bad for hobbyist and not occasional user.https://streamable.com/49qwg7I also noticed that black probe plug's leads from my second set and red probe plug's leads from my last set are different. The former is from metal and the latter has some kind of diode in it? Why is such a difference?

author: artag
author_rank: Super Contributor
timestamp: November 15, 2022, 10:32:10 pm
content: Shrouded probes are a solution for a non-existent problem.I can see 4mm plug leads might get left connected somewhere and the live ends touch on the bench. But 4mm plug leads are mostly not shrouded. I only have shrouds on DVM cables .. with handheld points on the other end. So an accident requires that I unplug the leads from the meter, leave the unplugged ends lying around, and then probe some high-energy circuit with the disconnected probes.The only time I unplug DVM probes is to swap them over to the current socket. There's no reason to leave them unplugged. The vanishingly small chance of that happening and not some other fatal error is easly beaten by all the inconvenience of them, such as the lack of stacking, the incompatibility with unshrouded sockets etc. etc.Absurd.

author: Black Phoenix
author_rank: Super Contributor
timestamp: November 16, 2022, 03:57:38 am
content: Quote from: artag on November 15, 2022, 10:32:10 pmNot really, if for some reason they come undone like your meter falling from a certain angle they could come undone and make contact with a energised part.Plus if you have problems of using them in unshrouded terminals there are adapters for it.Example of shrouded leads who stack and can be adapted:

author: coppice
author_rank: Super Contributor
timestamp: November 16, 2022, 07:57:36 pm
content: Quote from: Black Phoenix on November 16, 2022, 03:57:38 amThose stackable shrouded connectors are pretty much the standard for power instruments, like power quality analysers, these days. If something gets tugged, the chances of something going bang are pretty low with those things.

author: tooki
author_rank: Super Contributor
timestamp: November 17, 2022, 12:28:58 am
content: Quote from: VK3DRB on November 13, 2022, 11:34:59 pmCurmudgeony much?When have youeverseen multimeter probes come with stackable banana plugs? I’d think that’d make it impossible to meet CAT ratings, which most probes seem to endeavor to meet. (The entire measurement setup’s CAT rating is that of the lowest rating of any component used.) That’s why safety (shrouded) banana plugs are standard these days, and safety is a good thing, ya know? And it’s not like that is something new, they’ve been standard for, like, 25 or 30 years now… As for what’s on the market today, only cheap garbage meters have safety banana jacks that don’t accept basically any shrouded banana plug on the market. (Well, and the 8.5 digit metrology multimeters that have banana binding posts, but they’re not claiming to be CAT rated.)As for Probe Master: they give you the choice of five different types of male banana plugs: safety and unshrouded, each in right angle or straight; or straight with retractable shrouds (plus a few female banana options, and pin plugs), on a bunch of different lead lengths (custom lengths by request). If you order a version incompatible with your meter, that’s entirely your fault, not theirs.Why 3D print some nonsense when you can easily buy adapters to do what you want? I have a couple of safety-jack-to-unshrouded-plug adapters for the odd occasion when I want to use probes with a power supply, for example. You can get both temporary ones, or semi-permanent adapters that you push in and then turn an internal set screw to expand the plug so that it tightly locks into the non-safety banana jack or binding post.

author: tooki
author_rank: Super Contributor
timestamp: November 17, 2022, 12:42:28 am
content: Quote from: artag on November 15, 2022, 10:32:10 pmThe only absurd thing is how nearly every single assumption you’ve made is wrong. As others have shown, safety banana leads are available and quite common, including stacking ones. I like using them wherever possible because they can’t short out on anything. A couple of adapters handle compatibility with devices that don’t accept them. You can even get stacking plugs with retractable sheaths that plug into everything but are sheathed when possible.There also exist binding posts that accept safety banana plugs, giving total flexibility on e.g. bench power supplies. (I’d love to see these displace ordinary banana binding posts altogether.)

author: Black Phoenix
author_rank: Super Contributor
timestamp: November 17, 2022, 04:07:04 am
content: Quote from: tooki on November 17, 2022, 12:42:28 amOne of the first companies I remember using with that design was TTI-AIM in their Bench PSUs.That kind of design is in my opinion the best of both worlds. I'm with Tooki on this one. Or the type that is shrouded but doesn't have binding posts. If you need a way to connect a wire there are adapters for such -https://fr.farnell.com/en-FR/staubli/22-3007-22/plug-safety-clip-on-red/dp/1085557https://uk.farnell.com/schutzinger/sdk-799-rt/safety-quick-release-terminal/dp/3224560

author: tooki
author_rank: Super Contributor
timestamp: November 17, 2022, 07:30:05 am
content: Quote from: Black Phoenix on November 17, 2022, 04:07:04 amYep, I love those for lashing together impromptu test leads. Then if it turns out to be something I use a lot, I’ll make a soldered version.