Milli-ohm evaluation of Binding post banana & alligator with HIOKI RM3542A

[Kiriakos GR]

As always I started one investigation about something that interests me, and I ended discovering due my own observations interesting new information's.

What it would happen if you use 3500 Euro equipment to evaluate items worth 0.5 to 1 Euro ? Naturally you learn new things.
New things which are of interest of people who care for precision.

Precision down to Milli-Ohm this is important also for inspection of Kelvin (four wire) harness, so you to verify if cables at your portable LCR or bench-top LCR , they are good to use of half damaged?

Second crucial information this is evaluation of parts that you should use or avoid, when you are planning to make your own Kelvin cables for your quite expensive multimeter this having ability for four-wires measurement due binding post bananas.

Did you think that manufacturer of such multimeter, he installed female binding post bananas which out awareness speaking of their own manufacturing quality?
Yes, contacts resistance and also quality of cooper all were inspected.     


I am not scientist but my measurements bellow they did awaken few more of my brain cells and from now and own, I will be more selective when I need to select materials for special projects.   

[Kiriakos GR]

Original Hirschmann BUELA30K (banana plug) this has long history and good reputation as high power banana plug, this able to tolerate up to 32A.

Possibly due patent expiration, these days BUELA30K this is available and from Asian factories.
Such an Asian reproduction item was evaluated by ITTSB blog and I am happy to report even lower contact resistance than of what I have tested so far with HIOKI RM3542A.

My advice to all about which type of banana plug so you to select for your application?
a) BUELA30K type would be my first choice for connection over a power supply, but not for connecting (using it ) over multimeter terminals. 
This banana plug design creates lots of mechanical force and this also translates to pressure at female banana inner walls.
Multimeter banana terminals does not tolerate high pressure due the fact that they are made of plastic.

b) Non BUELA30K product with long pin and single spring (mechanical design) this is by far more suitable for multimeter.
This is Max 16A and by far more friendly to female plastic banana terminals.