Resistance of a connector

We are using six ERNI connectors (6 male , 6 female) to transfer 95 Amps from one PCB to another.
The Male one is part number 214550
The female one is 214548
These are “Microspeed” connectors.
Page 5 of the catalog states that the contact resistance is <=4milliohms
(Does the 4 milliohms refer to one “blade” connection, or all 5 blades in one connector?)

ERNI microspeed connector datasheet
https://www.erni.com/en/products/sh...ON]=10&cHash=ee2ea0acb1947f633c823de0e47846b9

Each contact has a resistance of <= 4mΩ.

Thanks, regarding the above connectors (Male and female), what do you think is the thickest PCB copper that they can be soldered to and still gaurantee a reliable connection?
All the shield pins will be soldered to ground copper and all the connector blade pins will be soldered to the same copper net on the PCB.

Whatever the thickness of your copper, a good soldering profile should be able to make reliable connections. What is the duty cycle of the 95 amps that your board will see? Will all six connectors (30 blades) be used for this current (or less than 3.5A per blade)?

With proper board thickness and all 30 blades carrying the current, I don't see a major problem with your design.

Each contact has a resistance of <= 4mΩ.

Click to expand...

..thanks, thats according to "test 2a of IEC60512"...the thing is, its not possible to find out what temperature that test was done at...and the per contact resistance would increase significantly at thigher temperatures, so the 4milliohms value doesnt mean too much to us unfortunately.
The attached ERNI connector catalog on page 5 , speaks of this test.

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Whatever the thickness of your copper, a good soldering profile should be able to make reliable connections. What is the duty cycle of the 95 amps that your board will see? Will all six connectors (30 blades) be used for this current (or less than 3.5A per blade)?

With proper board thickness and all 30 blades carrying the current, I don't see a major problem with your design.

Click to expand...

thanks, the customer now changed their mind, it is 65A now......and we have 6 of the above connectors to carry the 'go' and 'return' of this, however, four of the contacts are reserved for signals, so we only have 26 contacts and the 6 pairs of shields to carry this 65A 'go' and 'return' current.

Page 5 of the attached catalog says that at 100degc, each contact can only carry 3.4A, and the shield of one connector can only carry 4.8A.....so we have 117.2 Amps of current carryign capability at 100degc, and need to carry 65A*2 = 130A of current ('go' and 'return')...i think we have had it?

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Also, we may need to solder all 5 contact pads, and all 8 shield pads, (of a single connector) to the same copper plane on the PCB, (ie the shield and all the contacts would all be the same net on the PCB). Do you think this would be possible on say 2oz copper?...and still give reliable solder joints?

I don't know what your application is, but at 100°C, I would say that we have crossed over into new territory. At that temp, I would not use SMD technology - the solder becomes too weak at higher temps and that is all that is holding your connectors to the board. I would look for high current THT connectors and use them. Not only do you have to deal with the high temp, but the temp rise from the current flow. You are looking at watching your connectors flow themselves off your board - that is probably the reason that the manu spec'd the current so low at the higher temps.

I also wouldn't even begin a design until the customer had completely nailed down his specifications (this sounds like a poorly spec'd military project - "oh, we need this... no, now we need that... oh, by the way, we also need...").