Making my own DMM leads - Page 1
Forum section: electronics / testgear

author: HobGoblyn
author_rank: Unknown
timestamp: March 22, 2020, 06:47:04 pm
content: Hi all.I'm a beginner so be easy on meI've now got two VC8145 bench meters than I'm very happy with and also have two cheapish hand held.Only problem is the leads are crap.I bought a Pomona test lead set for £29, and it's very good.However I don't really want to spend £90 at the moment on 3 other sets and on my bench, a 4ft lead is simply too long, I need more like 2ft (60cm)Looking on RS, I can get 5m of red and black for £29.90 (£14.50 each). This is 3.9mm outer sleeve in silicon rubber.https://uk.rs-online.com/web/p/products/7481995/The thing I'm not sure is what probes and banana plugs to buy to complete the leads. Any advice greatly received (would prefer UK suppliers with the virus restricting things)Thanks

author: skander36
author_rank: Frequent Contributor
timestamp: March 22, 2020, 10:25:47 pm
content: For me this pair of Brymen leads works very good . They are gold plated and very flexible.https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads

author: Fungus
author_rank: Super Contributor
timestamp: March 23, 2020, 01:30:09 am
content: Quote from: skander36 on March 22, 2020, 10:25:47 pmYep, not all leads cost 30 quid.You can get gold/silicone test leads for a few $$$ on eBay, but those Brymen leads are very good value (1m long though!)

author: myf
author_rank: Regular Contributor
timestamp: March 23, 2020, 05:21:15 pm
content: Hello,I don't know how are expensive leads.I make my own from (1)silicon wire (2)awg14 [or awg16, 14 is slighty better] with(3)Chinese banana 4mm-32A jacks (with screw) and (4) Chinese insulated alligator clips.(1) silicon wire is much nicer too use. Since I discovered it, now I build all my leads with this silicon wire.(2) awg14 has an incredible low resistor per meter, awg16 is very good. The most resistor wire is a low-price alligator clip at about 1.5Ohm and 1.5eur on ebay.(3) these alligator have a "nose" with springs and can also be use as female banana (but not insulated in this case).(4) fully insulated are clever for resistor measures. Our fingers can't change the resistor measure. It isnot small alligator with a soft skin, but a 55mm long one.I already use more than 10m of these awg16 and awg14 wires. Cable I lost, little gifts, and so.Price is about 1-1.5eur per meter. banana 4mm 0.4eur x 4 for a wire, 0.6eur x 2 for aligator clips : A couple of two leads cost maybe 5eur each.Have a nice day, without viruses for you and your family.

author: HobGoblyn
author_rank: Unknown
timestamp: March 23, 2020, 05:36:08 pm
content: Thanks. I purchased a couple of rolls of AWG13 silicon test wire from RS (one I linked to in OP). Didn’t have AWG14And ordered a few 4mm banana jacks from Farnell. Ordered from these companies as I get next day delivery. Will get some from eBay when the world gets more back to normal

author: AVGresponding
author_rank: Super Contributor
timestamp: March 24, 2020, 12:10:18 am
content: Quote from: HobGoblyn on March 23, 2020, 05:36:08 pmOne thing I would add, is be wary of buying this kind of item from ebay. The jacks/sockets are almost always garbage quality, and it's not too unusual to end up with copper-coated aluminium wire.As always YMMV, but in my experience it's worth spending that little bit more to get guaranteed quality.There are good quality items like this on ebay, but they'll not be much cheaper, if at all, and the ebay shops that sell the good stuff can be hard to find unless you know who you're looking for.

author: tkamiya
author_rank: Super Contributor
timestamp: March 24, 2020, 01:22:52 am
content: All of my test leads are cheap ones from Amazon. I don't measure any high current or high voltage, so safety is not an issue. I never had any problems....Banana plug only come in two varieties. One with sleeve on it and one without. Almost all test leads you can buy today are former, and that's what your multi-meters use.

author: AVGresponding
author_rank: Super Contributor
timestamp: March 24, 2020, 02:21:37 am
content: It depends what you're measuring I suppose.If it's low currents/resistances/voltages cheap leads will give you misleading results.If it's high currents/voltages, there could be safety issues with insulation resistance, or current capacity.For the middle ground, ok you can get away with it.I do have some cheap leads myself, I just don't use them for nV or kV, mOhm, nA or >10A measurements.

author: MegaVolt
author_rank: Frequent Contributor
timestamp: March 24, 2020, 08:59:26 am
content: For a device of this accuracy class, you can take any probes and wires with aliexpress.

author: Fungus
author_rank: Super Contributor
timestamp: March 24, 2020, 09:30:55 am
content: Maybe I'm just ignorant but I can't imagine making your own leads is easy.The wires and banana plugs part is easy enough but decent probes for the other end of the wires? Not so much.Sure, there's plenty of spring hooks and stuff available out there but I don't recall ever seeing DMM-style probes in a DIY form.

author: AVGresponding
author_rank: Super Contributor
timestamp: March 24, 2020, 10:41:31 am
content: I can't say that I've seen them either.The only test leads I made myself (aside from the usual general purpose croc to croc lead) is a Kelvin clip set.

author: HobGoblyn
author_rank: Unknown
timestamp: March 25, 2020, 10:51:40 am
content: Quote from: Fungus on March 24, 2020, 09:30:55 amThanks.Yep I've come to realise I wont be making my own probe leads, ordered another ponoma dmm lead.But for my learning when I'm building basic breadboard circuits, I can make and use a few grab hook style leads to save leads all over my bench. Can also make shorter banana to banana leads to go from my breadboard banana jacks to my power supply.I can also tuck the cables from my DMM under my oscilloscope to keep things tidy. Otherwise leads would be everywhere, especially when using 4 DMM's at once. See attached picsSorry for the silly questions, my first lab and I'm trying to keep things as tidy as possible

author: AVGresponding
author_rank: Super Contributor
timestamp: March 25, 2020, 04:49:37 pm
content: There are no silly/stupid questions, only people that remain silly/stupid because they fail to ask questions...I like these from Pomona, because they aren't horribly expensive, and also the sheath is retractable so can be used with more equipment:https://www.mouser.co.uk/ProductDetail/Pomona-Electronics/6366?qs=sGAEpiMZZMuYRc8VvBrIhhTUnUOvodOEjFvbwhZ2hgc%3D

author: GreyWoolfe
author_rank: Unknown
timestamp: March 25, 2020, 11:05:09 pm
content: Quote from: tkamiya on March 24, 2020, 01:22:52 amIt's not always about safety but how the leads affect your readings. I started with an ANENG 8009 for my company toolbag and moved to the Fluke 101. I swapped out the original leads on both because my requirement is accurate low Ohm readings. The Brymen leads I use are far better than the OEM. I trust my Brymens, do you trust your cheapies?

author: wizard69
author_rank: Super Contributor
timestamp: March 31, 2020, 04:06:52 am
content: I'm not convinced in the value of building your own versus buying test leads with molded on ends. The only time it would become an issue is in current handling capacity is important. This especially for patching meters or instruments together. It is even more important when it comes to the actual test probes as feel is so important for hand held tools.Patch cords are not that expensive, simply buy one or two each time you order parts from your favorite component vendor. Soon you will have more than you can use at one time. The only time to build your own in my mind is when you can't get what you need from stock.