Stäubli SLK425 & MULTILAM Gold plated banana plugs – Mini Review
Intro
In the past seven years of operation of ITTSB Blog, I did gain significant experiences and knowledge regarding science of electrical calibration.
While electrical calibrators and high precision multimeter both are designed under strict specifications’, a true reliable electrical measurement this is possible when human error this is minimal and when test leads in use these are of acceptable quality.
In the past five years at ITTSB testing lab I was using only a specific middle-priced product design of banana plugs, this is banana body with single spring load bar this be in parallel to solid 4mm copper axle.
Regarding test cables I was using double insulated 1.5mm2 (Red & Black), possibly made in Taiwan product, this distributed in Greece with out branding.
By using such three pairs of cables 100 cm long it’s one, I was able for several years to perform my electrical tests and to obtain respectable test results.
End of 2018, I did spent respectable amount of money, so to upgrade my test leads from high-end (medium priced) to high-end of (high priced) category.
Stäubli brand is the one in Europe this including banana plug product codes in their products portfolio, them qualifying enough for use at electrical calibration test leads.
Regarding electrical wire construction, Stäubli brand again is the one also producing fine stranded wire.
Here the word fine, this translates to single copper core at diameter of human hair.
An high number of such (fine copper strings) they are forming a single fine stranded wire at 2,5 mm2 (which is highest available diameter).
Most powerful Stäubli brand patch-cord these including SLK425 type plug and fine stranded wire at 2,5 mm2 and it is specified for up to 32A.
ITTSB Blog December 2018
End of November 2018 I was involved buying a used lot of Multi-contact products from the USA at sweet price.
Originally I was aiming for a quantity of XDK1033 alligator clips.
Among them was old stock of SIL425 gold plated banana plugs (20cm patch cord), product quality seems much higher than of what I had touch so far.
Unfortunately for me, these cables were not at equal colored pairs.
So I made the decision to spend approximately 83 Euro so to buy what ever it is required (Stäubli products) so create my own finest collection of finest patch cords and banana wire leads .
Nowadays end of December 2018 I have managed to own a complete selection of best-in-class of wires for calibration testing for medium up to highest counts multimeter.
My collection includes:
Four pairs of SIL425 gold plated banana plugs (20cm patch cord), these will serve creating a chain of four multimeter and voltage linearity inspection by comparison.
Two pairs of L41 banana MULTILAM these be at length of 50 centimeters its wire, these will be used for direct connection at portable calibrator (such best-in-conductivity and stable in connection banana plugs they will eliminate bad contact issues at critical measurements’ as for example micro and Milliamperes).
Wire alone this is dual insulated PVC Stäubli 2,5mm2, this be incredibly useful also for very high resistance measurements’ in which wire isolation material this has increased importance.
Additional one pair of L41 banana MULTILAM these be at length of 100 centimeters its wire.
This will be useful when voltage or current source equipment's they have bench top format and they are at different height from device under test.
Shunt resistance testing by using DC power supply at the range of 10A is another good reason for having such cables.
And finally one pair of Series SLK425-E these are at length of 100 centimeters its wire.
This product has fully isolated housing at banana plugs, and as such it is recommended for higher voltages up to 600V RMS and at 32A.
My own tweaking for decreasing cost of ownership was buying SLK425-E ready made wires at 2M length, and to use portion of their wire length for making my very own cables collection according my preferences.
Stäubli 2,5mm2 wires evaluation:
Regarding banana plugs in use all three Stäubli products as for example the older design of SIL425 gold plated banana plug, and newer design of SLK425-E gold plated banana plug, among with L41 MULTILAM gold plated banana plug, they are all identical in contact resistance and electrical specifications’, they all belong at top-of-the-range (highest quality) of Stäubli products.
Therefore statistics worth noted can be taken by the evaluation of its wire resistance at specific length.
Available lengths are at 20 & 50 & 100 centimeters.
In those tests again HIOKI RM3542A dedicated resistance meter (7 ½ digit) gave detailed and measurements’ which you can trust at the range of few milliohm.
In detail:
20cm wire this measure 2.2960 milliohm (end to end of banana plug).
50cm wire this measure 3.9970 milliohm (end to end of banana plug).
100cm wire this measure 7.0240 milliohm (end to end of banana plug).
Just for comparison I will mention that my older banana plugs (non gold plated) among with 1.5mm2 wire, at about 90cm length they measure a little higher than 12 milliohm (end to end of banana plug).
Final thoughts and conclusion
I was have to read too many scattered documents so to discover that people working at electrical metrology sector they do now accepts a small portion of ppm changes these caused due the use of gold plated plugs and or of solder type at soldered cables.
Composition of solder this changed in our decade, dangerous substances which were used before they are now banned from the market and because of that we cannot have any more availability of lowest Low-thermal solder wire.
Therefore in a multimeter of 8 ½ digits with one million counts resolution, we should now ignore from our measurement a roughly sum of 6 ppm of changes, and justify this quantity as acceptable variation caused due latest Low-Thermal capabilities of the materials that we use at 2019 on planet earth.
According my understanding in the future we could possibly witness such a 6 ppm unavoidable Low-thermal deviation this to now listed in the column of measuring uncertainty in a high-end multimeter calibration report.
Now, from a less academic point of view, I will say that I am witness of one market in which most industries trying to cheat in product quality so to boost profitability by them delivering something looking as 100% copper wire.
Especially low-end factories in China, they now trying to mimic appearance of a good quality banana plug, by the use of lot of gold paint which identical paint it is used over Christmas decorations for a Christmas tree.
For people like me, who we do not accept to be fooled (cheated) and our non-negotiable requirement this is having few but reliable tools in our ownership, the number of choices are much fewer.
While I am greatest enemy of Stäubli pricing policy, I have to admit that products alone, they are made according highest quality and standards.
For example even the humble L41 banana (MULTILAM), this has product design which is a product of lots of thought and attention to detail (work of a serious product designer).
The round barrel which this accepts the wire so to be soldered, this is impressively designed and it does assist soldering process in a way that 100% successful soldering this would be warranted.
Stäubli wire, silicone or PVC insulation, both are what you expect that they would be, speaking of pure copper wire.
Regarding wire diameter selection, I will use Spartan method of interpretation because this review it is not sponsored, but paid due my own wallet as is 95% of ITTSB blog content.
Feel free reading electrical metrology requirements for calibration test of several DUT and components, then determine your own needs and requirements and then make a choice and stick to it.
My very own choices about type and quantity and quality of test leads for calibration tests are the ones which a calibration enthusiast should also follow, so measuring uncertainty to be solely a problem of the measuring equipment or of the DUT.