Grounding vs Regular Crimp Terminal

[dknguyen]

I was going through some Molex datasheets and found two seemingly identical crimp contact terminals, except one was called a grounding crimp terminal and the other one wasn't. What's the difference?

 

[justDIY]

i've seen grounding terminals from Gardner Bender that are unplated copper, versus normal crimp terminals that are nickel plated ... perhaps this is the difference?

 

[dknguyen]

Not this case

No..not in this case. THey are both either Au or Sn plated with a Ni underplating. Here are two of the series:

**broken link removed**

**broken link removed**

 

[zevon8]

The only thing I can see different is that the grounding pins specify "4 points of electrical contact". Maybe this means that the crimp barrel has a more "postive" biting surface, as well as the mating surface is designed slightly different to ensure a better electrical contact.

I have seen some of the AMP circular connector pins that have a slightly raised edge on them that will cut into the mating pin and wire, giving an almost air tight connection, similar to the telephone wire crimps used on punch down strips.

 

[dknguyen]

Yeah, I noticed that 4-point thing too except that for the connector "family" page it says that too so it seems it applies to the regular ones too.

 

[zevon8]

You're right, and I see that it actually refers to the female terminal, it's bifurcated, giving 4 fingers that touch the male blade. Odd thing also, the CAD mechanical drawing for both parts is the same drawing number, RSD-42817-001.

 

[hjames]

If you look at page 4 of the data sheet (assuming you aren't scared away by the mass of Japanese on the first two pages), it notes that the 1 in the "0131" part refers to it being a "make-first/break-last", and lo-behold the length of the "131" part is slightly longer.

Hot swap connectors like to have the ground contact hit first (hence the oddball grounding comment) in order to prevent -VCC from showing up on sensitive data lines.

Finding useful information on the websites of connector companies is a bit hit-and-miss. Just rely on the mechanical drawings...

 

[dknguyen]

Whew

Well, I wasn't able to decipher the information that 4rth page to come to your conclusions, but what you say does make sense.