Silicone vs. PVC measuring leads - Page 1
Forum section: electronics / general

author: dangerousamateur
author_rank: Contributor
timestamp: May 05, 2024, 01:37:54 pm
content: Hi guys,I'll need a new set of measuring leads, I prefer something like this here:https://www.staubli.com/global/en/electrical-connectors/products/t-m-products/products-for-test-accessories/test-probes-2-mm-and-4-mm/test-probe-with-measurement-cable-xp-484.htmlThese are available in PVC and silicone.What would you chose for daily use?

author: madires
author_rank: Super Contributor
timestamp: May 05, 2024, 01:50:31 pm
content: Most prefer silicone: more flexible, higher heat resistance, but also more expensive

author: Siwastaja
author_rank: Super Contributor
timestamp: May 05, 2024, 02:47:16 pm
content: Get silicone test leads if you can afford them. Much easier to handle and less likely to tangle; not burning from accidental touch from iron tip is a plus. Only if on a tight budget, and saving on test leads allows you to get something more important, consider PVC.

author: nctnico
author_rank: Super Contributor
timestamp: May 05, 2024, 02:53:54 pm
content: Quote from: dangerousamateur on May 05, 2024, 01:37:54 pmSilicone all day long as these are easier to untangle and don't get stiff when cold. Silicone test leads aren't that much more expensive.

author: BrokenYugo
author_rank: Super Contributor
timestamp: May 05, 2024, 03:23:14 pm
content: Cost aside I can't think of a situation where I would chose PVC wire insulation over any synthetic rubber option.

author: mendip_discovery
author_rank: Super Contributor
timestamp: May 05, 2024, 03:51:51 pm
content: PTFE, because I like my measurements to be accurate.

author: madires
author_rank: Super Contributor
timestamp: May 05, 2024, 03:55:25 pm
content: Silicone is easier to damage, e.g. when pinched, and is more prone to generate static electricity.

author: wraper
author_rank: Unknown
timestamp: May 05, 2024, 03:56:45 pm
content: PVC wires become very stiff at low temperatures, and can even snap when bending if it's like -30oC

author: bdunham7
author_rank: Super Contributor
timestamp: May 05, 2024, 04:13:53 pm
content: I'll be the contrarian here and point out that the extreme flexibility of silicone can cause leads to knot up in strange ways and also allow strand breakage. Certain expensive Fluke silicone leads are especially prone to this issue and they end up with intermittent connections near the probes. Also, silicone seems to attract all sorts of garbage that sticks to its surface while PVC seems to stay clean. I have plenty of both and have no issues tolerating either one, but one thing that can be an issue with test leads or other cables--like soldering iron cords--is that PVC wires will stay where you put them but silicone wires are often completely limp and will go rolling or dropping into inconvenient places. OTOH, silicone does resist accidental burns and most chemicals. YMMV

author: soldar
author_rank: Super Contributor
timestamp: May 05, 2024, 05:36:58 pm
content: PVC sheaths of alligator clips are an abomination. They soon become rigid and have to be cut away so the alligator is left without insulation.I need to replace all my alligator clips ASAP because they are all a PITA.

author: Nominal Animal
author_rank: Super Contributor
timestamp: May 05, 2024, 05:49:53 pm
content: I use both – but I damn overly plasticized PVC (whichsomesellers claim is silicone) to the deepest of hells.The plasticizer will slowly leach out, especially if stored in a warm place. If you store such leads in a compatible plastic pouch or tub, the plasticizer will act on the container plastic, and you'll end up with PVC leads embedded in your container. Not just "melted in", butfusedto the container plastic at the molecular level.Thus, I am wary of PVC leads that feel more flexible than ordinary. When flexibility isn't that important, I'm happy with PVC. I cannot afford stuff like PTFE (Teflon) insulated wires.

author: mzzj
author_rank: Super Contributor
timestamp: May 05, 2024, 06:46:14 pm
content: Quote from: bdunham7 on May 05, 2024, 04:13:53 pmThis is also my experience with Fluke silicone test leads. Strands break inside the cable.Im not sure if they have improved the design but this was real epidemic years ago.Some silicone sheathing is allso very weak mechanically and prone to tear. Cheapo silicone cable from china/ebay has been better than the wire used on fluke probes.

author: blue_lateral
author_rank: Contributor
timestamp: May 05, 2024, 07:16:34 pm
content: In my opinion, nothing beats rubber. They tangle less and the dielectric strength is sky high. The downside is they will eventually perish in a decade or two. Also rubber (EPDM) test leads are getting extremely hard to find. Apparently the Chinese don't make the wire or make so little of it that you rarely if ever see it as an option.Silicone test leads have improved a lot in the last few years. They are less sticky than they used to be, and tangle less than what you probably expect. Of the choices given in the original post, they win hands down. Still, once you've had rubber test leads it is hard to accept anything else. PVC has no redeeming qualities in my opinion. It tangles easy, gets hard in the cold, gets hard with age, and leeches plasticizer. I avoid them whenever possible.

author: IanB
author_rank: Super Contributor
timestamp: May 05, 2024, 07:18:23 pm
content: Quote from: mzzj on May 05, 2024, 06:46:14 pmSo, what's the experience with ProbeMaster? Do their products stand the test of time and robustness?

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: May 05, 2024, 07:37:59 pm
content: Quote from: IanB on May 05, 2024, 07:18:23 pmI've had good experience with ProbeMaster (so far). No issues, and the quality seems okay for the price.

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 07:41:24 pm
content: Quote from: mendip_discovery on May 05, 2024, 03:51:51 pmdo you also hire a electrician with a pipe bender to lay out your test leads???https://www.qedelectric.com/product/detail/3197407/IDEAL-INDUSTRIES-74-100

author: Bud
author_rank: Super Contributor
timestamp: May 05, 2024, 07:44:25 pm
content: Quote from: mzzj on May 05, 2024, 06:46:14 pmNot inside the cable, the problem was with weak crimp inside the probe body, I wrote about the failure mode here:https://www.eevblog.com/forum/chat/x-raying-fluke-tl-175-probed/msg4908254/#msg4908254

author: soldar
author_rank: Super Contributor
timestamp: May 05, 2024, 10:09:33 pm
content: Quote from: coppercone2 on May 05, 2024, 07:41:24 pmAccess deniedError 16www.qedelectric.com2024-05-05 20:22:30 UTCWhat happened?This request was blocked by our security serviceFew things are more ridiculous than feeling requests from outside the USA can be a security threat. Not uncommon though.

author: 2N3055
author_rank: Super Contributor
timestamp: May 05, 2024, 10:24:28 pm
content: Quote from: Bud on May 05, 2024, 07:44:25 pmMy Fluke modular probe set had cable strands broken..I kept all the probes and crocodiles, and replaced cable+shrouded bananas with UNI-T ones that I had and are so far holding better than original... Go figure...

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 10:36:36 pm
content: Quote from: soldar on May 05, 2024, 10:09:33 pmits a toy beer bottle opener shaped like a electricians pipe bender and it could be used for bending test cable sized teflon wires (preposterously stiff)

author: Zoli
author_rank: Frequent Contributor
timestamp: May 05, 2024, 10:39:26 pm
content: Quote from: blue_lateral on May 05, 2024, 07:16:34 pmBelden 8899 is still in production, and I'm using on some of my (homemade)leads.

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 10:46:36 pm
content: that is something you REALLY need to do a cable inspection for because its HV and also disintegrates.The worst is if you forget to do a cable inspection for a HV probe you wired with rubber.

author: David Hess
author_rank: Super Contributor
timestamp: May 05, 2024, 11:06:31 pm
content: I have a red and black spool of rubber insulated test lead wire which I have been using for decades, and it works great although the rubber insulation eventually gets stiff and cracks. I recently bought a set of silicone rubber insulated test leads from Probe Master and they are excellent also. PVC wire for test leads is my last choice.Spools of silicone rubber insulated test lead wire is on my buy list.

author: blue_lateral
author_rank: Contributor
timestamp: May 05, 2024, 11:06:54 pm
content: Quote from: Zoli on May 05, 2024, 10:39:26 pmAlso Carol and Philmore still have EPDM wire, though I suspect Philmore's is really just one of the other two repackaged. I've also been making my own leads since the demise of Oldaker.

author: shabaz
author_rank: Frequent Contributor
timestamp: May 06, 2024, 12:27:14 am
content: For red and black wire for thin test leads, I've been using very flexible 24 AWG wire from CPC/Farnell. It's very low cost (£0.99 for 5m lengths) and 'feels' great in use, too. It has 133 strands. However, it is PVC, so it has limitations like temperature range.In terms of multi-color, I was looking for reasonable-priced flexible wire not for multimeter probes, but for logic probe type applications, and noticed an online store calledBNTECHGO, and placed an order for 26 AWG wire (they offer other sizes too). It seems to be silicone (doesn't melt when I apply a 330 deg C soldering iron to the insulation). In terms of stranding, the 26 AWG cable had 30 strands of 0.06 mm tinned wire.They sell reels at what seems a fair price for low-volume use, but they also sell packs of 10 colors in 5 ft (1.5 m) lengths. Unfortunately, gray is missing from the 10-pack, so if the full color code is needed, a reel of gray would also need to be purchased.On the negative side, the BNTECHGO wire is initially really stinky. After a month, the smell reduces, but it's not gone (but now, it only smells if you put your nose within a few inches of it). Maybe I'm being too picky, but it's still irritating enough that I'd prefer an odorless wire supplier, even if it costs slightly more, and I will check the normal distributors at some point.

author: soldar
author_rank: Super Contributor
timestamp: May 06, 2024, 08:12:14 am
content: Quote from: coppercone2 on May 05, 2024, 10:36:36 pmYes, I was just commenting on the practice of too many American sites who block outside requests.I did see the page though as I have little trouble getting around these kinds of things.Another web site that does this isAccess DeniedYou don't have permission to access "http://www.homedepot.com/" on this server.And I shop there regularly.On the other hand Bestbuy.com does not ship outside the USA but instead of blocking outside requests, when they detect a foreign IP they show a notice:International customers can shop onwww.bestbuy.comand have orders shipped to any U.S. address or U.S. store.The Internet used to be much more open but it is becoming a set of isolated islands which, IMHO, is not good.

author: dangerousamateur
author_rank: Contributor
timestamp: May 06, 2024, 09:10:15 am
content: I dont think I ever used anything else but PVC for lab applications and never questioned it.Silicone lines are known to me of course, I used a lot for RC Stuff.I just need a new set of measuring leads with banana tips, and when I did a search yesterday I found the silicone option by accident.I will take the silicone ones then, thank you for your sharing your insight

author: Nominal Animal
author_rank: Super Contributor
timestamp: May 06, 2024, 09:54:46 am
content: Silicone elastomeres do outgas after manufacture, so if yours have an unpleasant smell, put them somewhere well-ventilated, out of direct sunlight or other UV sources, for a couple of months.(If you're interested in the subject, look up "silicone outgassing"; the Rothka, Studd, Tate, Timpe paper is available online. For thin silicone elastomere structures, even post-curing doesn't seem to speed that up too much: only "aging" in a well-ventilated space without UV to degrade the silicone, is guaranteed to work.)

author: BILLPOD
author_rank: Frequent Contributor
timestamp: May 06, 2024, 05:57:47 pm
content: In my opinion, the best test leads are the ones that come with Brymen meters,https://brymenmeter.com/brymen-bl21s2-t4sc.htmlThey have the little 'Lanterns' that screw on the sharp probe, so you can use crocodile clips that are for 4mm banana plugs. Or plug them into your PSU. VERY handy.

author: tooki
author_rank: Super Contributor
timestamp: May 06, 2024, 07:42:53 pm
content: My 2¢:All else held equal, silicone is usually better. But I’ve softened my anti-PVC stance over the years, and I’ll explain why.Regardless of insulation material, there are differences between individual brands and types. So first, let’s review the qualities we want in a test lead:- flexibility (limpness) so you aren’t fighting the wire- doesn’t “take a set” (doesn’t have “memory” of how it is bent)- toughness, so the lead isn’t damaged in ordinary use- safety, especially when used at mains voltage or higher- long life- resists tangling- doesn’t pick up dust- useful temperature range- low electrical resistance/adequate cross section for the intended useSome of these properties are contradictory. The biggest one is that limp wire is more liable to tangle.So what influences those properties?Flexibility is the result of two things: conductor stranding (huge number of ultra fine strands is desirable) and insulation material.Both silicone and PVC can be equally soft — or stiff. I’ll take a high quality PVC over low quality silicone. Some silicone is designed only for its thermal properties, but without any consideration given to anything else. I’ve seen silicone cable with a silicone jacket so fragile that I could strip the 3x1.5mm2 jacket using my fingernail. (Really.) Another — a thin supposedly-test-lead-wire from Cal-Test had so much memory as to be useless for test leads. (And it really was the insulation, as it has memory even if all the copper is pulled out!!) I just got some thin Stäubli silicone wire today, and its insulation is so tough that none of my wire strippers can strip it — the insulation just stretches (to over 2x!) and bounces back. A lot of silicone is very “sticky”, grabbing onto any dust it comes near. That’s why it’s often dusted in talcum powder. If you clean it off, you may need to reapply talcum. Some silicone (like the wire Pomona sells and uses for Pomona and Fluke test leads) is a bit less limp, but has a “satiny” finish even without talc, and doesn’t tangle as much.There are huge differences in PVC, too. It varies wildly in its initial softness, and varies wildly in how well it ages. Some plasticizers migrate or evaporate, making the wire stiffer and getting into nearby stuff; others are very stable and stay put. PVC is generally not a dust magnet. Toughness varies a lot.As far as safety goes: you not only want the insulation to resist damage, but you want damage to be easily visible. This is why most high-quality test lead wire these days is double-layer, typically a white inside layer and the red or black outer layer, so that if the insulation gets damaged, you see the white and know to replace it. Test lead wire tends to have thicker insulation than regular wire.Silicone resists heat damage (it won’t melt; at many hundreds of degrees, it will burn, leaving ash) and stays soft at very low temperatures. PVC will melt if you touch it to your soldering iron, and turn unusably stiff at winter temperatures.With a gold-standard brand like Stäubli, both the silicone and PVC are top notch. I have used PVC of theirs that is decades old and still very, very soft. Both their PVC and silicone are extremely soft and tough. I can recommend either without reservations, but since the silicone is only slightly more expensive, I buy that. In top-quality test lead wire, a lot of the cost goes into the extremely fine stranding, so the insulation impacts the final price a bit less.Fluke/Pomona silicone is excellent quality, but as others have said, some of their products had poor strain relief. Their cheapest PVC (like in TL70 probes) gets very stiff with age, but doesn’t get sticky.Probe Master is outstanding; they only do silicone.Another good brand is SKS/Hirschmann. Not quite as soft as Stäubli or Fluke/Pomona, especially the larger gauge PVC. Their ultra-small test leads (the ones with “DuPont” style connectors) use extremely soft PVC that is very nice.In a nutshell, I’ve become more willing to accept very high quality PVC, which can actually be softer than silicone, at lower cost. In particular at small gauges (like 0.25mm2/24AWG), getting good silicone gets a lot harder, to the point that I’ve mostly moved back to PVC for that. Too many small silicone wires aren’t really designed as test lead wire and have fragile silicone with too much stiffness and memory.

author: tooki
author_rank: Super Contributor
timestamp: May 06, 2024, 07:46:21 pm
content: Quote from: mendip_discovery on May 05, 2024, 03:51:51 pmNobody sells multimeter test leads with PTFE (Teflon) insulation because Teflon is way too stiff. Consequently, nobody makes really finely stranded wire with Teflon.There are certainly measurement applications where Teflon is used, but certainly not as your everyday probe wire.

author: KE5FX
author_rank: Super Contributor
timestamp: May 06, 2024, 08:07:55 pm
content: Quote from: tooki on May 06, 2024, 07:42:53 pmThat being said, it's disturbing how much I like thischeesy Chinese 30AWG hookup wire.It is easy to strip with fingernails but also hard to damage the insulation accidentally. Especially nice when point-to-point wiring is needed on dead-bug prototypes.

author: coppercone2
author_rank: Super Contributor
timestamp: May 06, 2024, 10:41:54 pm
content: thats good wire for the lab if you have good work ethic and planninglike clean work space until a project is put away or finishedIMO you don't need 3000V rated wire, if you are careful

author: nctnico
author_rank: Super Contributor
timestamp: May 07, 2024, 09:15:29 am
content: Quote from: tooki on May 06, 2024, 07:42:53 pmMy opinion on these is different. I have two sets but made my own replacements using silicone wire.

author: tooki
author_rank: Super Contributor
timestamp: May 07, 2024, 09:17:43 am
content: Quote from: shabaz on May 06, 2024, 12:27:14 amWhat is its actual cross-section? Because the specs cannot be correct: they say it’s 24AWG (which is 0.22mm2) but they also specify it as 0.5mm2. Both cannot be true.

author: bdunham7
author_rank: Super Contributor
timestamp: May 07, 2024, 03:58:26 pm
content: Quote from: tooki on May 06, 2024, 07:46:21 pmWell, actually these are teflon-core coax. But yeah, they're stiff.https://www.fluke.com/en-us/product/accessories/test-leads/tl2x4w-ptii

author: tooki
author_rank: Super Contributor
timestamp: May 07, 2024, 04:04:06 pm
content: Yeah, looks like RG316. But I’d argue those fall squarely into the “not everyday probes” I explicitly qualified in that reply.

author: shabaz
author_rank: Frequent Contributor
timestamp: May 07, 2024, 06:46:56 pm
content: Quote from: tooki on May 07, 2024, 09:17:43 amHi! The 24AWG is incorrect (I compared it to 24 AWG enamelled copper wire, and the ECW is much thinner), it's 0.5 mm^2. Unfortunately CPC has no stock of the red wire of that type currently, only black wire.While I was at it, I took a photo of various wires, attached below. The TPE wire (third in the photo) has attracted a lot of dust that sticks to it : ( It might wipe off with a wet-wipe but I didn't try that. The RS wire (last in the lineup) had some dust that wiped right off, it's very smooth and non-sticky.

author: Gyro
author_rank: Super Contributor
timestamp: May 07, 2024, 06:53:45 pm
content: Note that only the Concordia ones are double insulated / damage evident. This will be important for some applications.

author: bdunham7
author_rank: Super Contributor
timestamp: May 07, 2024, 07:11:02 pm
content: Quote from: tooki on May 07, 2024, 04:04:06 pmWell, actually the marketing for those has two selling points. The first is being able to get accurate resistance readings more conveniently or where kelvin clips won't work. The other is that you can use one set of probes for all your measurements without exceeding the voltage limits of the SENSE connections since the meter automatically disconnects that side when you select voltage ranges. This is how I use mine--as everyday probes that stay connected full time. They work just like any other probe set except my low resistance readings are very accurate. I have the earlier, more flexible version, the newer ones are usable but not very nice.

author: David Hess
author_rank: Super Contributor
timestamp: May 07, 2024, 11:33:22 pm
content: Quote from: tooki on May 06, 2024, 07:46:21 pmFinely stranded Teflon insulated wire does exist, and in every color. We used it in high temperature applications. But I have no idea where we sourced it from.

author: tooki
author_rank: Super Contributor
timestamp: May 08, 2024, 12:02:56 am
content: Finely stranded? Easy.Really finelystranded? I have never seen it in PTFE.For example, for 24AWG/0.25mm2:Regular stranded: 7 strandsFine stranded: 19 strandsVery fine:~ 40 strands“Really fine”: ~65-130 strands.There’s simply not much point in the higher strand counts because their flexibility is lost on the PTFE. 19-strand 24AWG PTFE is readily available, but I’ve never seen or heard of finer ones.

author: m k
author_rank: Super Contributor
timestamp: May 08, 2024, 10:21:08 am
content: What material is the one that US electrical wiring has and some ants like to use for other purposes?Or are they just boosting vibes, wonders a curious mind.

author: David Hess
author_rank: Super Contributor
timestamp: May 08, 2024, 02:30:57 pm
content: Quote from: tooki on May 08, 2024, 12:02:56 amThe wire was probably 24 AWG (I never measured it and I do not think the spools were marked.) and definitely had at least 40 silver plated strands. It was used for internal wiring of load cells between terminal strips and Teflon insulation had to be used because part of the manufacturing process included baking in an oven after assembly. I assume finer stranding was used to get as much flexibility as possible in a confined space. The wire might have been custom ordered and not a standard product, because the economy of scale when manufacturing is such that custom orders do not cost any more than standard ones.

author: Zero999
author_rank: Super Contributor
timestamp: May 08, 2024, 05:32:06 pm
content: Quote from: wraper on May 05, 2024, 03:56:45 pmDoes the LCD even work at such low temperatures?

author: shabaz
author_rank: Frequent Contributor
timestamp: May 08, 2024, 06:32:43 pm
content: Quote from: KE5FX on May 06, 2024, 08:07:55 pmThanks for the tip, I ordered some after seeing your comment, it arrived today and it looks great! I often use 30 AWG wire (mainly Kynar for prototypes etc), but the 30 AWG silicone wire from Amazon will be a nice low-cost alternative for general work, plus it may be useful for creating ultra-fine jumper wires if needed.

author: tooki
author_rank: Super Contributor
timestamp: May 08, 2024, 07:49:08 pm
content: Quote from: Zero999 on May 08, 2024, 05:32:06 pmProbably not if it actually got that cold, but I suspect a common scenario is that the meter is at or near room temperature (taken outside from a warm truck or building), but that the wire chills much, much faster in use due to its surface area to volume ratio.Fun fact, though: some meters, like the Fluke 80 series, have internal temperature sensors used to automatically adjust the contrast voltage to the LCD!