its 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)
Yes, 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 is
Access Denied
You 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 on www.bestbuy.com and 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.
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
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.)
In my opinion, the best test leads are the ones that come with Brymen meters,
https://brymenmeter.com/brymen-bl21s2-t4sc.html They 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.
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 use
Some 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.
PTFE, because I like my measurements to be accurate.
Nobody 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.
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.
That being said, it's disturbing how much I like this
cheesy 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.
thats good wire for the lab if you have good work ethic and planning
like clean work space until a project is put away or finished
IMO you don't need 3000V rated wire, if you are careful
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.
My opinion on these is different. I have two sets but made my own replacements using silicone wire.
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.
What 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.
Yeah, looks like RG316. But I’d argue those fall squarely into the “not everyday probes” I explicitly qualified in that reply.
What 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.
Hi! 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.
Note that only the Concordia ones are double insulated / damage evident. This will be important for some applications.
Yeah, looks like RG316. But I’d argue those fall squarely into the “not everyday probes” I explicitly qualified in that reply.
Well, 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.
Nobody sells multimeter test leads with PTFE (Teflon) insulation because Teflon is way too stiff. Consequently, nobody makes really finely stranded wire with Teflon.
Finely 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.
Finely stranded? Easy. Really finely stranded? I have never seen it in PTFE.
For example, for 24AWG/0.25mm2:
Regular stranded: 7 strands
Fine stranded: 19 strands
Very 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.
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.
Finely stranded? Easy. Really finely stranded? I have never seen it in PTFE.
For example, for 24AWG/0.25mm2:
Regular stranded: 7 strands
Fine stranded: 19 strands
Very 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.
The 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.
PVC wires become very stiff at low temperatures, and can even snap when bending if it's like -30oC
Does the LCD even work at such low temperatures?
That being said, it's disturbing how much I like this cheesy 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.
Thanks 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.
PVC wires become very stiff at low temperatures, and can even snap when bending if it's like -30oC
Does the LCD even work at such low temperatures?
Probably 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!