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I am designing a board that has to carry up to 32 A of continuous current through it, and as such I need a cheap and compact method of permanently mating the 6 mm² wire to the PCB. Since I have very tight size constraints, I cant use big industrial connectors that would usually be used for such applications.

My idea is to simply do a through hole solder on both sides of the PCB. The entire PCB and including about 10 cm of the wire will also be completely submerged in thermally-conductive potting resin, which combined with a wire grommet, should prevent any force on the connection point, that could tear off the wire.

My question is how reliable is this form of contact or if there is a better solution to this problem that doesn't require bulky or expensive connectors?

I have also looked at press fit connectors as well but have not found enough information on how to actually use them and how they look like.

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    \$\begingroup\$ stranded or solid wire? If solid: that sounds dangerous, because invariably, the wire will put mechanical stress on the board and the junction. if stranded: you need to make very sure you're not bending/wiggling the wire close to the potting, if 32 A is what you're carrying: single strands can progressively break off if one end is fixed somewhere, and the other moves. generally, though, cable-in-potting sounds pretty safe. Generally, I think a somewhat bulky connector is the way to go here, if alone because soldering thick cables to boards takes a lot of heat and ain't pretty. \$\endgroup\$
    – Marcus Müller
    Commented Mar 10, 2022 at 13:21
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    \$\begingroup\$ Use a terminal strip; leave the metal part exposed and connect your wire with a ring lug to it after curing. \$\endgroup\$
    – rdtsc
    Commented Mar 10, 2022 at 13:49
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    \$\begingroup\$ there's also isolated wire-to-boad push-on connectors, like:tme.eu/de/en/details/tbg-5.0-kw-3p/pluggable-terminal-blocks/… \$\endgroup\$
    – Marcus Müller
    Commented Mar 10, 2022 at 14:11
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    \$\begingroup\$ I would look further into a connectorized arrangement. Did you look into a multi-pin connector, say something with 35-40 1 A (derated) contacts? \$\endgroup\$
    – SteveSh
    Commented Mar 10, 2022 at 20:23
  • \$\begingroup\$ @MarcusMüller thank you for your ideas. The wire in question is only going to be stranded, so no worries there. The problem with plugable connectors like that is that, while the smaller ones are usually pretty cheap and small, when you get to the ones that are rated for 30+A they usully become very bulky and expensive quickly. But i will maybe reconsider my options as well. \$\endgroup\$
    – Aleš Kramžar
    Commented Mar 11, 2022 at 7:14

1 Answer 1

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Electrically, a plated through hole generally works pretty well here.

For mechanical strength you can add additional holes to the PCB to provide strain relief.

enter image description here

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