[volt-nuts] Good quality but reasonably priced 4mm plugs?

[Todd Micallef]

Tony,

I have looked for the perfect connector for all types of measurements. I
came to the conclusion that the type of measurement will dictate the type
of connector. I prefer the solder type and would never consider using a
screw type for any of my cables. I am sure they have an application
somewhere, but it gives me peace of mind knowing that the cables won't pop
out and create a hazardous situation. I have read that for low level
measurements, use a direct wire connection, or a low thermal spade lug that
has an air-tight crimp and then soldered for strength. This is not cheap to
build, the crimp tool can be very expensive.

I have found that Multi-Contact makes a good range of plugs as an
alternative to Pomona. I recently purchased some of the SLS425-SE/Q for
some generic sheathed cables. These are made of gold plated brass and are
rated to 1kV and max 32A. These look heavy duty but not too expensive.

The SLS205 series looks to be a decent low voltage test connector. I do not
have any experience with these connectors but you might want to make some
cheaper jumper cables for power supplies. The LK425-Z is another low
voltage but higher current than the previous connector. It is the only
sheathed, retractable, stackable connector that I have found from a
reputable company.


The silicone cable is probably the best choice of cable to use with any of
these connectors. Pomona sells the cable #6733 in red and black. You may
also want to consider shielded cable with an external ground/guard
connection. I have a couple sets of the Fluke 5440A-7002 cables and I can
tell the difference using them in high resistance measurements compared to
the Pomona 5290A low thermal cables.

I have been waiting to build a couple sets of Fluke 5440A-7003 test cables.
I have some Belden 8719 cable, gold plated copper spade lugs from JS
Willey, and some generic blue pomona patch cables that will be cut in half.
The crimp tool is more expensive than all the other components.
Unfortunately, I could not find a better alternative for the low ohms
measurements.

Check Farnell for the Multi-Contact connectors. I had no trouble finding
them on the Newark site. The cost will probably be twice what you want to
pay, but you can build them to your specs so you can make them as short or
long as needed.

Todd



On Fri, Aug 15, 2014 at 7:44 PM, Tony <vnuts at toneh.demon.co.uk> wrote:

> Can anyone recommend some decent banana plugs, preferably stackable, for
> making up test leads? There don't appear to be many different types on Ebay
> - the cheapest have a single screw connection which loosens off at the drop
> of a hat, and in any case the plug, at 16mm, is too short for my HP 34401A.
>
> There are plenty of more expensive, audio type plugs which may be better
> quality but almost invariably have all metal, uninsulated bodies - not good
> when plugged into a high current power supply!
>
> I'd like some which I'd be happy to put 6, 8 or even 10amps through, eg.
> for low-ohm measurements, but also be good for low level or precision
> measurements. Would screwed, crimped or soldered connectors be best? I
> believe crimped joints can be best for low thermal EMFs - at least until
> the copper wires start to oxidise.
>
> I know Pomona make some decent connectors but the prices are quite steep -
> I don't really want to spend more than $4 or so for a pair if possible.
> Maybe I need to spend more for some low thermal EMF connectors or leads and
> use cheaper ones for general purpose and higher current usage, but I'm not
> prepared to spend $100 or so for a pair of low thermal HP leads.
>
> I'm in the UK so USA suppliers have a big disadvantage because of the high
> shipping costs and the tax and customs handling charges which rarely seem
> to apply to Chinese goods.
>
> What do you use?
>
> Thanks,
>   Tony
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