What do you call the wire used for testers? - Page 1
Forum section: electronics / projects

author: drakejest
author_rank: Regular Contributor
timestamp: June 06, 2025, 10:53:11 am
content: Hello i would like to create some custom test leads for the my new tester that i just recently bought. My question is what type of wire does these tester use? My Testers are Cat IV and III rated. What type of wire is being used for these type of testers? i would like to order some of them.Are these silicone wires? but silicone wires are soft, the leads it came with are kind of hard coated. Can anyone help me identify what type of wires do testers typically use so that i can buy a spool of them

author: BradC
author_rank: Super Contributor
timestamp: June 06, 2025, 11:36:51 am
content: I have both silicone and pvc test leads here. I prefer the silicone, but both work. I find the most important thing to me is flexibility and that comes from lots of smaller conductors. After-market I've found that easier to find/get in silicone.

author: tooki
author_rank: Super Contributor
timestamp: June 06, 2025, 11:40:06 am
content: “Tester” is a much too vague description of the test equipment you’re thinking of, since there are probably thousands of kinds of testers, for any variable or quantity one can possibly test. Even within electronics and electrical, there are countless different ones.You should just tell us exactly what kind of equipment you’re using.With that said, based on your stating that yours are CAT III and IV rated, I’m assuming they’re some kind of electrical tester that can be used on fairly high energy mains circuits, so fundamentally the kinds of test leads used on multimeters and the like.If so, what you’re looking for is, well, test lead wire. It’s made specifically for that purpose, in either silicone, rubber, or PVC. (PVC is cheaper and in some ways more mechanically robust, silicone is softer, doesn’t get stiff at low temperatures, and doesn’t melt if it touches a hot object. Rubber is somewhere in between, but much rarer than PVC and silicone these days.)Modern, high quality test lead wire uses extra-soft, extra-thick, double-layer insulation (typically white inside), so that if the insulation is damaged, the white becomes visible under the black or red. For high flexibility, test lead wire is very finely stranded. (Where ordinary stranded wire uses 19 strands, test lead wire uses far more, on the order of 65-500 strands.)Typical test lead wire is 18 or 16AWG (0.75 or 1 mm2) though thicker is available.Are you sure the “hard coating” on your wires isn’t just… grime and age? Perhaps on PVC?

author: drakejest
author_rank: Regular Contributor
timestamp: June 06, 2025, 12:23:48 pm
content: Quote from: tooki on June 06, 2025, 11:40:06 amwhat do you call these "moderm high quality test lead wires" i need the technical term for these so i can look them up on the shop

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: June 06, 2025, 12:27:31 pm
content: Google 'rubber high voltage test wire' and you'll get lots of results to down select.

author: drakejest
author_rank: Regular Contributor
timestamp: June 06, 2025, 12:30:38 pm
content: Quote from: BradC on June 06, 2025, 11:36:51 amDo you have a part number or something more technical than just silicone, i have been looking around and in digikey they have a filter for "test-leads" : are these the ones?https://www.digikey.ph/en/products/detail/belden-inc/9899-002500/7008489

author: BradC
author_rank: Super Contributor
timestamp: June 06, 2025, 12:45:27 pm
content: Quote from: drakejest on June 06, 2025, 12:30:38 pmAbout quarter past three.tooki asked for more detail. More detail required.

author: tooki
author_rank: Super Contributor
timestamp: June 06, 2025, 02:27:01 pm
content: Quote from: drakejest on June 06, 2025, 12:23:48 pm1. I literally name it in the reply. However, because2. You didn’t tell us, even after I told you to, what kind of test equipment it’s for, I can’t be sure it’s what you need. I won’t give any more information or clarification until you give us the information needed.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 06, 2025, 03:05:07 pm
content: Pomona 6733-2 and Pomona 6733-0Lovely stuff.

author: Gregg
author_rank: Super Contributor
timestamp: June 06, 2025, 04:42:46 pm
content: I don't know where you are located, but I have used a lot of this wire from Amazon:https://www.amazon.com/NAOEVO-Silicone-Electrical-Breadboard-Automotive/dp/B0DDXMQDCTIt may not be the super premium wire like Pomona, but it has real silicone insulation, tinned fine strand real copper and is reasonably priced.

author: TimFox
author_rank: Super Contributor
timestamp: June 06, 2025, 05:48:58 pm
content: Quote from: drakejest on June 06, 2025, 12:30:38 pmThat Belden wire and its black equivalent are typical for voltmeter leads.PVC insulation (sometimes a bit sticky on the outside) and rated for 5000 V insulation, with flexible conductor.

author: Simmed
author_rank: Frequent Contributor
timestamp: June 06, 2025, 06:27:15 pm
content: Quote from: drakejest on June 06, 2025, 10:53:11 amhttps://www.mouser.com/c/wire-cable/test-lead-wire/?type=CAT%20IV

author: David Hess
author_rank: Super Contributor
timestamp: June 06, 2025, 07:39:59 pm
content: It is called "test lead wire". I have spools of red and black rubber insulated 18 AWG test lead wire which are like 40 years old and they are still good and works fine, but today I think I would buy silicone rubber insulated wire.

author: drakejest
author_rank: Regular Contributor
timestamp: June 07, 2025, 06:29:57 pm
content: Okay let me summarize everything i have gathered taking into consideration all of your suggestions and commentsThe name of the wire is literally "test lead" wire. I will be usingDigikeyas my supplier as it ships globaly (mouser also works but their website is currently throwing an error on my end). Under cable type we select "test lead" option.I filtered the voltage rating to be 5000V up, 5kV seems to be the most common voltage rating, with 10kV as a better (and slightly more expensive) option for CATIV requirements (i would assume), there is also a 20kV option bydaburnas the absolute best available currently , but i dont like the color option,sheating diameter,guage, and number of strands.I have also noticed that the material selection left aligns with what have been mentioned PVC ,Silicone, and Rubber. or a combination/variant of these 3.I end up settling with the 10kV option, and it was fairly easy to choose as there is only 1 brand, and has been mention by terry on a previous comment: Its from [url-https://www.digikey.ph/en/products/detail/pomona-electronics/6733-0/737851]Pomona. It has a black and red option,wire diameter fits my existing plugs, its also Silicone based as most of you prefer, also from the image it looks double insulated, as mention by tookiMy concern now is use case matters? i would assume that you want as high of a voltage rating you can get and call it a day. But my use case for it is to be used as a extra long leads for a voltmeter, the rating shown on the socket on my voltmeter says CATIV. though the highest usecase idd be reading is 500VDC from solar panel strings. I also plan on making custom test lead for my power analyzer/power logger.Should i go for Pomona , or try looking for something else?

author: Gyro
author_rank: Super Contributor
timestamp: June 07, 2025, 07:13:02 pm
content: When it comes to Cat IV, the terminations and how you terminate the wire into them, strain relief etc. are just as important as the wire itself. Lead Cat rating applies to the whole lead as an assembly.

author: tooki
author_rank: Super Contributor
timestamp: June 07, 2025, 08:04:37 pm
content: Quote from: drakejest on June 07, 2025, 06:29:57 pmI think that is miscategorized. It’s not nearly finely stranded enough to be considered test lead wire. (And IIRC, it isn't on Daburn’s website.)Quote from: drakejest on June 07, 2025, 06:29:57 pmIt’s nice stuff. I’ve got some of it at home and have used it for various custom leads. It is not the softest silicone out there, but it’s tough silicone.If you can find a source for it, look for Stäubli’s Silivolt series. One member (I forget which model number) is double insulated. Their silicone is astonishingly tough, yet super flexible. But super hard to find. The distributor I used to get it from stopped carrying it.Quote from: drakejest on June 07, 2025, 06:29:57 pmThe more important question is, do you need to have a specific CAT rating for safety or legal reasons? If so, the don’t underestimate what Gyro said: the CAT rating of the entire test setup is only as high as that of the lowest-rated component used in it. You mention your “existing plugs”, but if they aren’t CAT rated (and the majority of banana plugs out there aren’t), then you won’t have a CAT rated setup. If you are not 100.000% certain your plugs have the CAT rating you require, buy new ones that definitely do.

author: David Hess
author_rank: Super Contributor
timestamp: June 07, 2025, 08:15:32 pm
content: Quote from: drakejest on June 07, 2025, 06:29:57 pmThis is what I find on Mouser which is what you found. It is too bad that it is not in more colors:https://www.mouser.com/c/wire-cable/test-lead-wire/?insulation%20material=Silicone%20Rubber&voltage%20rating=10%20kV&wire%20gauge=18%20AWG&instock=yBelden has some options for insulated in rubber that might be better, but are much more expensive because of how much you have to buy, at least from Mouser.