Potting Connectors

Question

I work for a company manufacturing electronics. We have a few products where we pot boards into enclosures. Where it is done the incoming connections are always soldered for fear of condensation inside pockets in connectors and bad connections after potting. However soldering is labor intensive.

I'd like to know if people here have experience potting connectors in manufactured products. Are there specific connectors that are OK but others not so? If so, what kind would you suggest (screw terminal, etc) or do you recommend entirely against it for what reasons?

Answer 1

It is recognized in the industry that the most vulnerable or unreliable point of a system is where connections are made. Many companies will opt for solder connections rather than plug/socket for this reason especially on wires going to circuit boards.

In my experience I have found that potting this type of push-on connector can cause a thin film of compound to impregnate the mating surfaces and this can have the effect of reducing the surface contact area. This in turn can mean that the resistance of the contact increases and, under load conditions the remaining contact surface degrades more rapidly.

Worse still is that some compounds are exothermic when they cure and can cause distortions in the mating surfaces because physical pressures build up during the cure process.

I'm not saying there aren't compounds available that won't degrade a surface contact connection but I'm not aware of any.

Answer 2

Whether or not this is useful will depend on your configuration, but quite a while back I did a design where the top of the connectors was left exposed so the potting didn't cover the entire connector and only barely covered the top of the PCB.

Just a bit of an idea worth considering and for screw blocks I'd imagine it would work quite well as long as the volume of potting mix is well controlled so it doesn't enter the contact area.