DIY Low EMF cable and connectors

[Shock]

They could be called breakout, splitter, Y cable, cable pants or cable splice kits if there is such a part.
The ones I have seen are way larger for mains power or telecoms and this doesn't look like a crimp part at all.

It's got to have strain relief so I think they are spliced soldered glued and insulated.
They would be better soldered anyway especially using a never fail splice technique.
I wonder if there is a book on how to make more complex splices.

[quarks]

Hello Shock,

thanks for your reply.
Splicing is nothing I would think of, for my very high accuracy metrology application.
What I know so far, crimping should be the best for this kind of low EMF cables.
Solder with Cadmium could be another option, but I do not have it and would probably not even use if I could get it.
 
The "thing" I am looking for is something like in my above pictures or maybe like the attached pic.
What I hope to find can also just be a kind of "heatshrink breakout" for 3 conductors.

thanks
quarks

[robrenz]

look here

[HighVoltage]

quarks,

If this AMP lug is still made, you can get it from Tyco
www.te.com
If you can not find it on their parts finder site, just send them an email with the picture attached.

I needed a few connectors that I could not find and within hours I got an answer.
Even better, they send out samples for free.
Hope this helps.

[Shock]

What I hope to find can also just be a kind of "heatshrink breakout" for 3 conductors.

There is also "cable pants" which I mentioned above but these break out normally into 2 or 4.

Then there is this wire splice

[quarks]

If this AMP lug is still made, you can get it from Tyco
www.te.com
If you can not find it on their parts finder site, just send them an email with the picture attached.

Thanks for your reply. I have done this and also had several conversations with TE in Germany. But unfortunately they did not know this spade lug and did not find a similar product they can offer. I do not know if they also contacted/asked US colleagues about my request, but maybe it is worth another try to contact them again.

Bye
quarks

[quarks]

There is also "cable pants" which I mentioned above but these break out normally into 2 or 4.

Thanks again
I will have a closer look
Bye
quarks

[wiss]

Hello Shock,

thanks for your reply.
Splicing is nothing I would think of, for my very high accuracy metrology application.
What I know so far, crimping should be the best for this kind of low EMF cables.
Solder with Cadmium could be another option, but I do not have it and would probably not even use if I could get it.

Do one really need low thermal EMF solder here? When you solder two wires together (using splicing) there will be a large area connecting the two similar metals over a thinner dissimilar solder layer, the temperature going from copper to solder to copper should be very constant. Or do I miss something?

[babysitter]

Hi quarks,

if you want to attach several multi-stranded wires like this, I would simply use a oversized crimp terminal, shown in the image connecting just 2 wires for lazyness. No intermediate metal, no seebecking, no worries (please prove my reasoning  )

To get the cables that should go out in one direction into a nice parallel shape, feed them through a block of plastic with parallel channels drilled or a comb-like structure.

Add heat shrink tube and fill with hot melt adhesive if desired (you can buy heat shrinking tube with glue inside).

Edit about solder:

Thermocouple people talk about a "Intermediate metal law" that basically says: Don't care at all if joints are on the same temperature - what I consider given at any moderate-sized soldering joint at the wire to pcb level.

[quarks]

short update

It is very strange, that the manufacturers do not seem to know about their own products.
I contacted AMP/TE and JST and send them my pictures of their original products and had several mail discussions, because I received feedback these products do not exist, which seems absurd, because I have them in my hands and they are from original FLUKE cables.

That is really frustrating  
Any ideas?

[quarks]

short update
I only have a few more parts to order, before I can finalize my experiments.

Although I spend way to much time and money for this, I am quite happy with the results.
My cables seem to be at least as good as my "reference" cables from FLUKE.
 
When looking at the original Fluke Low Thermal Test Lead Set (see att. picture 7003), I wonder why they choose to use a Nickel-plated banana plug, instead of a Gold plated banana or just another spade lug for the guard.

Because they ask for >1000$ for the set, cost for the plugs should be no reason at all. 
Does anyone know or have a guess why Fluke did that?

For my own DIY cables I have not yet decided what to prefer for the guard connection.

Maybe I will go for a plug-in type separable guard connector. This way I could easily go from no guard at all to 4mm banana or to a spade lug, whatever seems more useful for the task. Right now I alternate between 2mm or 4mm plug or maybe an Anderson Powerpole connection.

If anyone has other/better ideas/suggestions, please let me know.

bye
quarks
 

[robrenz]

.......When looking at the original Fluke Low Thermal Test Lead Set (see att. picture 7003), I wonder why they choose to use a Nickel-plated banana plug, instead of a Gold plated banana or just another spade lug for the guard. ........

bye
quarks

IMO thermal emfs are of no consequence on the guard terminal so that would make sense to me.

[quarks]

IMO thermal emfs are of no consequence on the guard terminal so that would make sense to me.

Hello robrenz,

yes that is right, for the guard there is no need for a low emf connection and therefore a Nickel plated banana will be no problem.

But why not did they mix spade lugs with 4mm banana or why not a least a Gold plated banana.
For the extraordinary high price and the expected very low volume they sell, I just do not understand why they should even try to save a few cents on these parts.

bye
quarks

[robrenz]

I agree, why skimp with a nickel plated banana jack on a already overpriced item?

[quarks]

Here is a short update for those who are still interested.
I achieved excellent results with the Fluke 5440A-7003 design (see att. picture of my final product).

[robrenz]

Here is a short update for those who are still interested.
I achieved excellent results with the Fluke 5440-7003 design (see att. picture of my final product).

Nicely done!  Are you able to determine if these are better performing than what you used before?

[quarks]

Hello robrenz,

with DC Volts and my "normal" but high quality MultiContact and Hirschmann banana plug leads, I see difference at best of about 1 µV compared to my >1000$ Fluke cables. With my DIY cable I get same (or very close within around 0.1µV) results, compared to the reference cable.

Besides the low emf aspect, for high resistance measurement also the better insulation material helps a lot to get more accurate results.
 
bye
quarks

[amiq]

Hello robrenz,

with DC Volts and my "normal" but high quality MultiContact and Hirschmann banana plug leads, I see difference at best of about 1 µV compared to my >1000$ Fluke cables. With my DIY cable I get same (or very close within around 0.1µV) results, compared to the reference cable.

Besides the low emf aspect, for high resistance measuremet also the better insulation material helps a lot to get more accurate results.
 
bye
quarks

So which parts did you use in the final design?

[wiss]

I've been thinking about this a bit...

What about DIYing the gold plating?

I googled and there are apparently a lot of "cheap" DIY gold plating kits around...

Do you or do you not want the nickel layer for low T-EMF applications?

Do you want a thin or thick gold layer?

Do you want pure gold or copper-gold?

[quarks]

So which parts did you use in the final design?

Here are the parts you need for the "Fluke 5440A-7003" design:
Belden 8719 or similar
high quality crimp spade lugs (pure copper, direct Gold plated, like the above metionend types or METAS Swiss special lugs see att.)
4mm banana plug (Fluke used Pomona and I used MultiContact)
high quality wire stripper (for Teflon insulation)
high quality crimper with exact fitting die for the lugs and wire size you use

[quarks]

I've been thinking about this a bit...

What about DIYing the gold plating?

I googled and there are apparently a lot of "cheap" DIY gold plating kits around...

Do you or do you not want the nickel layer for low T-EMF applications?

Do you want a thin or thick gold layer?

Do you want pure gold or copper-gold?

Unfortunately I have no experience with DIY Gold plating, so I hope someone else can share some information.
Sor far my guess is, the DIY plating is only for a nice shiny look and will wear off as soon as you tighten the screws on.

The gold should be electro plated with no layer between copper and gold. Gold thickness of 6 µm seems to be adequate.
In my research I had problems to find pure copper spade lugs (I even build my own small batch).
TE/AMP and JST answered to my request, they do only have tinnend lugs.
 
Direct Gold plating is normally not offered when you ask for plating in the industry. They always suggest to use a diffusion barrier, but direct plating can be done on special order.
My best offer was around 50€ min. order value (plus tax and shipping cost), when I send them blank (untinned) lugs.

[wiss]

...
Unfortunately I have no experience with DIY Gold plating, so I hope someone else can share some information.
Sor far my guess is, the DIY plating is only for a nice shiny look and will wear off as soon as you tighten the screws on.

Me neither, but SWMBO works with sputtering, and spontaneous were something like: "Thick layers will peal off due to the strain"
But then she mostly do compounds on metal/silicon.

Thickness will be linear to the time you plate it (?) Just run for a longer time...

The gold should be electro plated with no layer between copper and gold. Gold thickness of 6 µm seems to be adequate.
In my research I had problems to find pure copper spade lugs (I even build my own small batch).
TE/AMP and JST answered to my request, they do only have tinnend lugs.

6 um isn't that thick
Can "easily" be done in sputtering, which is very slow compared to electroplating.

Direct Gold plating is normally not offered when you ask for plating in the industry. They always suggest to use a diffusion barrier, but direct plating can be done on special order.
My best offer was around 50€ min. order value (plus tax and shipping cost), when I send them blank (untinned) lugs.

Without the nickel-barrier copper will diffuse through the gold and end up on the surface and oxidise, not good at all with copper-oxide there...
The nickel-layer will be thin and in very good thermal contact with both the copper and gold, no net EMF.

[robrenz]

IMO forget the gold and use bare copper and DeoxIT.  That is Agilents approach on their nano voltmeter.

[quarks]

IMO forget the gold and use bare copper and DeoxIT.  That is Agilents approach on their nano voltmeter.

When I send my request to the crimp lug manufacturers, I also asked for bare copper spade lugs, with the same result, they only offer tinned lugs.

So far (besides ebay) I have not found DeoxIT in Germany.
And with equivalent products from "Kontakt Chemie" I am not happy with my handmade lugs (see the one in the middle).

[robrenz]

If you want some machined from solid copper send me a drawing of the critical features and I will solid model what I would machine. They could have exact fit of wire and insulation diameters and slot width etc.. Tell me how many you would want and I will quote a price.