Silicone test leads - Page 1
Forum section: electronics / testgear

author: Jeroen3
author_rank: Super Contributor
timestamp: April 16, 2018, 11:26:09 am
content: We've just found a dozen or so broken test leads. They're all premium brand SKS Hirschmann MLN SIL, and they all suffer the same flaw.They break just after the plug because the insulation is flexible silicone.So, don't buy silicone test leads I guess?edit: Obviously these have been abused by pulling on the cable. The small plug make this very likely to happen.

author: Pinkus
author_rank: Frequent Contributor
timestamp: April 16, 2018, 11:34:09 am
content: my guess: this should happen only if they were frequently pulled at the cable and not at the connector.

author: 001
author_rank: Super Contributor
timestamp: April 16, 2018, 12:19:38 pm
content: You can see destroyed WIRE, not insulation!So cooper sucks and silicon wins!

author: noidea
author_rank: Unknown
timestamp: April 16, 2018, 01:09:07 pm
content: I have found something similar with Multi Contact / Staubli silicone DMM leads as well. I am using the shrouded ones with 90° and straight connector and find they always break in about the same spot at the straight connector end. My theory is that when they are plugged into test probes and are using them normally, this is the point they flex the most as the weight of the test of the lead is pulling on it. Over time the conductors fatigue and once they start to break failure becomes inevitable.If I can find the last one I cut apart I'll post some photos.

author: targit
author_rank: Regular Contributor
timestamp: April 16, 2018, 02:03:09 pm
content: Same thing has happened to 2 sets of fluke leads for me, each set lasted about 5 years in daily use. Easy enough to fix with new plugs, but a real pain when they fail while trying to track down a tricky short.

author: Fungus
author_rank: Super Contributor
timestamp: April 16, 2018, 03:41:34 pm
content: Quote from: Jeroen3 on April 16, 2018, 11:26:09 amYep. Stick to PVC, it flexes much less than Silicon.(and you'll also save some money at purchase time).Silicon is the test-lead equivalent of putting OLED displays in multimeters - initially attractive, reassuringly expensive, but ultimately high maintenance and very short lived compared to LCD.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 16, 2018, 04:05:36 pm
content: right. plastic can protect metal from breaking because plastic is a lot harder than metal and metal is a lot harder than silicone, made a lot of sense.

author: CopperCone
author_rank: Super Contributor
timestamp: April 16, 2018, 04:10:53 pm
content: Lol pvc test leads are mega fail. I would rather replace silicone. How can you stand pvc??Mine are a few years old and still ok.5 years of daily use is alot.. Not sure what you expect from the materials.. How old are your shirts buddy?

author: BillB
author_rank: Unknown
timestamp: April 16, 2018, 04:24:51 pm
content: I think you guys should just stop swinging your meters around like bolas. Your leads may last longer.

author: Fungus
author_rank: Super Contributor
timestamp: April 16, 2018, 04:28:58 pm
content: Quote from: CopperCone on April 16, 2018, 04:10:53 pmIt's not about aesthetics, they last longer because they act like springs. The whole length of a PVC lead is effective one big strain reliever.With PVC the multimeter will move across the bench before the leads are straight enough to get a solid tug on the copper inside. Not so with silicone.

author: PA4TIM
author_rank: Super Contributor
timestamp: April 16, 2018, 04:38:02 pm
content: Same here. A Pomona set within a month, Agilent set (is in all those years now around 50 cm left over) and some set I do not know the brand from. The red testlead from my Brymen 869S also within a few months. (daily use)

author: CJay
author_rank: Super Contributor
timestamp: April 16, 2018, 05:30:51 pm
content: My daily drive meter has a set of test leads that are in the region of 20 years old.Fluke Silicone.YMMV, if you treat stuff like crap it will fail.

author: targit
author_rank: Regular Contributor
timestamp: April 17, 2018, 01:20:53 am
content: I wasn't complaining about the lifespan, and as I said, simple to repair with a new connector, they always fail on the straight banana jack end for me.

author: ikrase
author_rank: Regular Contributor
timestamp: April 17, 2018, 01:41:21 am
content: I wonder if this is more of a problem with strain reliefs and the exact cable layout than the actual use of silicone.

author: tautech
author_rank: Super Contributor
timestamp: April 17, 2018, 02:20:42 am
content: Quote from: ikrase on April 17, 2018, 01:41:21 amSilicone is the problem without something to extend the bending moment, it's always gunna fatigue the conductor near the end on a connector. Preformed plugs and PVC cablingcanbe better in this regard.If DIY'ing it's better to add at least one layer of heatshrink on the cable at the exit point of the connector.

author: Hydron
author_rank: Super Contributor
timestamp: April 17, 2018, 07:46:51 am
content: I've had similar issues with the Pomona silicone leads (Fluke TL71 style, which are sold with various brandings). Ended up buying another set though, as the price, usability and availability were right. The old-style Fluke leads (TL75) seem more rugged and (I recall) have slightly lower resistance, but in my opinion don't feel as nice in use due to PVC insulation.Annoyingly some of the other Pomona products are let down by similar issues - e.g. their mini (3A) probes with replaceable tips are really useful for electronics (as opposed to electrical) work, but seem to suffer badly from high contact resistance developing between the replaceable tip and it's holder. Will need to investigate other brands in the future to try and find a more reliable replacement.

author: Muttley Snickers
author_rank: Unknown
timestamp: April 17, 2018, 08:07:15 am
content: On a side note, just the other day I came across a recent video of a UNI-T or Unitrend multimeter where at around 1:50 it showed testing of both the strain relief and fixed leads, I was rather surprised to see Unitrend going to this extent as they do not have much of a reputation in regards to quality control.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 17, 2018, 09:10:07 am
content: Quote from: BillB on April 16, 2018, 04:24:51 pm

author: nanofrog
author_rank: Super Contributor
timestamp: April 17, 2018, 09:37:12 am
content: Quote from: tautech on April 17, 2018, 02:20:42 amSilicone definitely needs strain relief.For DIY, heat shrink does a great job of it.Personally, I find adhesive lined does even better. Particularly on larger gauge wire.

author: xani
author_rank: Frequent Contributor
timestamp: April 17, 2018, 09:56:00 am
content: Quote from: Muttley Snickers on April 17, 2018, 08:07:15 amUni-T is weird. Some of their products look well designed and generally good bang per buck, others are utter fail. And some are just straight up funny, like multmeters without enough input protection... that have PCB layout for them, just not mounted them in. Very inconsistent.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 17, 2018, 10:12:41 am
content: If you're going to play the UNI-T game, may as well hit the casino tables instead with the moneyIt's a better gamble, and you may even win enough the one time to buy a Fluke with reliable generic leads

author: Edison
author_rank: Frequent Contributor
timestamp: April 17, 2018, 10:47:43 pm
content: When I was working in operational research and development laboratories we used super flexible silicone cables.When I finished my employment, I got a couple of them.The yellow measuring cords are still unchanged - thirty years old, the isolation of the blacks measuring cords broke down after about twenty years. They are so flexible that you feel - only silicon without wires - unfortunately I can not get it anymore.

author: SG-1
author_rank: Regular Contributor
timestamp: April 18, 2018, 04:11:28 am
content: If you store your meter with the leads wrapped around it, make sure that first wrap is loose, so it does not pull against the jacks.I used to unplug the leads for storage after every shift, with my 1980s model Fluke 27, that resulted in the jacks becoming internally loose & wrecking havoc with ohm readings. I then began to leave them plugged in & wrap them around the meter. I began to experience lead failure at the jacks. Now I make sure that first wrap is loose & does not pull against the meters jacks. We will see how that works out in a few years...

author: tautech
author_rank: Super Contributor
timestamp: April 18, 2018, 09:03:17 am
content: Quote from: SG-1 on April 18, 2018, 04:11:28 amPreformed 90obanana jacks are perfectly suited to wrapping leads around DMM's.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 18, 2018, 09:18:59 am
content: A loose first warp after following the 'angle' direction is the best way AFAIK to keep silly cone leads workingHave not lost any so far (cheapskate heaven)

author: Tinderbox (UK)
author_rank: Contributor
timestamp: November 09, 2019, 04:36:56 pm
content: I don't have any silicone test leads but plastic test leads seem to start to go hard at 15C or lower making more likely the plastic will split, My little UNI-T the strain relief is useless at this temperature and i bet the leads will split right where they emerge, So i am thinking about wrapping some tape or something to give some elasticity.I want to buy some Probe Master silicone leads but they are not available in the UK and with customs they are somewhere like £60 a pair when they can be bought in the US for like $15-20.

author: Terry01
author_rank: Frequent Contributor
timestamp: November 09, 2019, 04:50:30 pm
content: You'll get Probe Masters here in the UK for decent ££'shttps://www.simonselectronics.co.uk/shop

author: Tinderbox (UK)
author_rank: Contributor
timestamp: November 09, 2019, 06:06:41 pm
content: Thanks, More sensible prices.

author: Terry01
author_rank: Frequent Contributor
timestamp: November 09, 2019, 06:10:02 pm
content: No probs. I've bought a couple of sets from Simon and they are spot on. Nice leads and they fit into all my meters easy enough.

author: RoGeorge
author_rank: Super Contributor
timestamp: November 09, 2019, 06:19:50 pm
content: Quote from: Tinderbox (UK) on November 09, 2019, 04:36:56 pmAt those prices you may as well get a free multimeter included, if instead of probes you search for AliExpress DMMs with silicone probes.

author: Tinderbox (UK)
author_rank: Contributor
timestamp: November 09, 2019, 07:54:06 pm
content: I wrapped some "self amalgamating tape" around the strain relief on my little UNI-T UT125C doubling the length of the strain relief area allowing the cable to flex without bending too far that the plastic splits.I have been using insulating tape for years but after a few months it turns into a sticky mess, This self amalgamating tape does a much better job, A length of heat-shrink might have been even better but i did not want to de-solderer the captive leads.Have you see the review of the tiny little UNI-T UT125C it has some real protection, A ceramic fuse and two ptc and 3 movs, Perfect to shove in your glove box and i paid less than £14https://lygte-info.dk/review/DMMUNI-T%20UT125C%20UK.html

author: Marck
author_rank: Regular Contributor
timestamp: November 09, 2019, 09:13:32 pm
content: From a field technicians point of view test leads primary purpose is to stop the meter hitting the ground when you do something stupid. Before moving to fluke meters and leads i treated them as consumables and always had a spare set. But i just cant seem to break the fluke leads even after 5 years of use. I want probes with smaller probes but i need to wear these ones out first.

author: Terry01
author_rank: Frequent Contributor
timestamp: November 10, 2019, 01:41:25 am
content: Another place you will find people selling decent 2nd hand fluke leads and the likes is Ebay, just keep an eye out. Another set I have that I love are these ones.https://www.ebay.co.uk/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch

author: Hydron
author_rank: Super Contributor
timestamp: November 10, 2019, 07:47:10 pm
content: Quote from: Marck on November 09, 2019, 09:13:32 pmI assume you're referring to the old style fluke leads (the non silicone ones)? Cos the newer silicone ones made by Pomona are nice to use, unfortunately but do not last very well with heavy use in my experience.

author: Fungus
author_rank: Super Contributor
timestamp: November 10, 2019, 08:45:22 pm
content: You can get decent noname silicone leads for about $6 on eBay.

author: Terry01
author_rank: Frequent Contributor
timestamp: November 10, 2019, 11:31:06 pm
content: Quote from: Hydron on November 10, 2019, 07:47:10 pmI picked up a set of "old old" Fluke test leads from somewhere I can't remember. Some deal or other likely. They are Fluke branded but don't quite feel silicone.I am in bed just now but tomorrow I will post a couple pics of the connections. I have the old style fluke croc clips are slip on too, not screw on like the new ones. Those are Fluke branded too. I'll post a couple pics of those too.I thought at first they were bum deal leads and clips but after a good inspection I do believe they are real enough and just old. Maybe some of the older guys can confirm?

author: Marck
author_rank: Regular Contributor
timestamp: November 11, 2019, 02:38:01 am
content: They are on my 5year old fluke 174 which i don’t have with me to compare. My new daily use tool bag meter is a Fluke 374 the leads on that are TL75. If the newer leads are known to be unreliable I will go back to having a spare set in the case. A set of leads is much less than a 3 hour drive to a wholesaler to get a new set. Or just use the leads from the other meter.M

author: macboy
author_rank: Super Contributor
timestamp: November 11, 2019, 02:39:21 pm
content: Quote from: Fungus on November 10, 2019, 08:45:22 pmIn my experience, a lot of "silicone" insulated leads/probes on ebay are not silicone at all, but heavily plasticised (soft) PVC. With real silicone, you can drag your fingernail across the surface easily without scratching. The soft PVC is not nearly so durable. Silicone will also easily withstand direct contact with a soldering iron with no damage, while the PVC just melts away. Likewise for chemical/solvent resistance.