Quick-Disconnect Terminals Brass / Copper - Which is Best?

[DReynolds]

Hi all

So I've been researching a source for good quality female quick-disconnect terminals in the UK. I've found most tin-plated terminals are available in either copper or brass, mostly the latter, like these Perma-Seal terminals from Molex:

https://www.mouser.co.uk/datasheet/2...CTS-161345.pdf

Also these Dura-Seal terminals from TE:

https://www.te.com/commerce/Document...ocLang=English

Is there a reason why manufacturers like Molex & TE choose brass over copper as the base metal for quick-disconnects? I understand brass is less electrically conductive than copper, but is brass less compliant, and the female terminals therefore better able to sustain a friction grip?

Thoughts welcome

Thanks.

[DReynolds]

So I reached out to TE to request a part number for their tin-plated copper female disconnects with heat shrink sleeving. They responded with the same part number above. I replied with a link to their datasheet for that part. They came back to concede they don’t manufacture any female tin-plated copper disconnects with heat shrink sleeving.

I researched 3M next. These are their female disconnects with heat shrink. The specification states ‘ETP Copper’ for the material. However, scrolling down to the details reveals ‘Made of durable brass for good conductivity’. Further, the PDF datasheet also gives the terminal material as brass. So contradiction there too. I will reach out to them for clarification.

https://www.3m.com/3M/en_US/company-...4888569&rt=rud

Thus far, the only manufacturer of tin-plated copper female quick-disconnects with heat shrink sleeving I have found is Ancor. Unless there's are actually brass too...

[DReynolds]

Just to follow up, TE responded to confirm there was a contradiction in their specs and the datasheet, and that their female heat shrink quick-disconnects are in fact made from brass, and not copper. Their other products in that line (eg ring terminals) are made from tin-plated copper.

That leaves just Ancor that I know of that manufactures female heat shrink quick-disconnects in tin-plated copper.

So that leads me back to my original question, why do leading manufacturers choose to manufacture their female heat shrink quick-disconnects in tin-plated brass, as opposed to copper, when they manufacture other products in the same line from tin-plated copper? I read somewhere that brass has only 28% the conductivity of copper, so there must be a compelling reason for them to choose brass over copper?

Thanks

[Wotname]

SWAG - the resistance of the body of the a quick disconnect is of secondary importance. The resistance of the interface between each connector is the prime consideration.

Copper is more soft and malleable when compared with brass and so copper will deform more readily after each connect/disconnect cycle. Thus the interface resistance increases if the body is copper.

This is not an issue with ring terminals etc.

[dfelsent]

A guess:
For a quick disconnect terminal you need a combination of a decent spring behavior ( to ensure contact pressure), conductivity, forming ability (for the crimp) , ability to take a corrosion resistant coating, and low cost

Notice that the spring and malleability requirements conflict.

I think I’ve seen crimp connections with a second band around the crimp part but I don’t recall the application.


Take a look:

http://www.eaglemetals.com/copper/

[Spot]

DReynolds, welcome to CF.

Hard to say why brass rather than copper other that it works better for the application and/or is less expensive to manufacture. Some of the online ones (like evoltelectric.com pic below) describe their female connectors as tinned copper, whether this is 100% accurate I do not know.




It would be interesting to design an experiment to see the real loss in a quick disconnect pair. My guess is that the increased surface area starts to compensate for material selection and cross sectional area.

What are you planning to wire with these connectors?

I have enjoyed having a mini heat shrink gun and ratcheting crimper versus the old stamped 'cut and crimp' pliers and a random open flame for heat shrinking.

[Wotname]

Originally Posted by dfelsent

..........

I think I’ve seen crimp connections with a second band around the crimp part but I don’t recall the application.

...........

You may be referring to the TE PIDG connectors. As far as I am concerned, they are the gold standard of crimp connectors and I have used thousands or perhaps tens of thousands of them over the decades.

Unfortunately they don't have shrink insulation.

https://www.te.com/global-en/product...?tab=pgp-story

[GordMay]

Originally Posted by Wotname

SWAG - the resistance of the body of the a quick disconnect is of secondary importance. The resistance of the interface between each connector is the prime consideration.

Copper is more soft and malleable when compared with brass and so copper will deform more readily after each connect/disconnect cycle. Thus the interface resistance increases if the body is copper.

This is not an issue with ring terminals etc.

I never thought of that, but it makes sense.
Thanks!

[DReynolds]

Thanks guys

I meant to say above that it was M3 who also came back to confirm the contradiction in the specs, they also said they would get it rectified. So both TE & 3M had contradictory specs, but both confirmed their female heat shrink disconnects were brass.

@Spot I wasn't aware of E-Volt, their terminals look very interesting, and cheap compared to the competition. I've reached out to them for confirmation on the construction material for their female quick-disconnects, but going by their website, it would suggest they are copper. I wonder if they are manufactured in the US, and I wonder how they compare to Ancor?

The terminals will be for connecting to some breakers, and in the main for connecting to Carling V-Series switches. Some of these will be for circa 15A loads.

@Wotname I take your point. These will be installed and (hopefully) left in situ, so they won't be subjected to repeat connect / disconnect cycles.

I wonder - if brass has such inferior conductivity to copper, wouldn't that equate to increased resistance, which would in turn lead to heat for higher loads?

Thanks again for all your input

[GordMay]

Electrical Conductivity of Materials ➥ https://www.bluesea.com/resources/10...y_of_Materials
Conductivity of Brass ➥ https://www.copper.org/applications/...ctbrass02.html

Since brass disconnects won’t be able to increase their sectional areas (to achieve the conductivity that a copper part would have), copper disconnects should be (initially) more conductive.