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Mounting 0.4.3d using holes in PCB - earth question

Posted: Wed Feb 15, 2023 9:28 am
by pete12
Hi there

I am a little bit electronics noob, so please bear with me.

I have assembled a 0.4.3d board and want to mount it into a factory ECU case, and the case is conductive and the screw/bolts are conductive.

There are 3 holes that are available to mount the board but one hole goes through the body of a STP62NS04Z when it is laying flat on the PCB. The body connector of the STP62NS04Z is connected to the middle pin... but it doesn't seem to be directly connected to the Ground pin on the board.

I'm guessing it's not correct/safe to ground the body of the STP62NS04Z as it isn't already connected to ground?

Re: Mounting 0.4.3d using holes in PCB - earth question

Posted: Wed Feb 15, 2023 4:49 pm
by PSIG
The STP will not function if the tab is connected to the board or case. Typically, mounting would use insulating washers and non-conductive bolts or screws to ensure there are no unintended electrical paths. Nylon or other non-conductive hardware from online sources or the local store is popular.

Re: Mounting 0.4.3d using holes in PCB - earth question

Posted: Thu Feb 16, 2023 9:36 am
by pete12
Thanks - I ended up using non conductive washers and filing down the thread of the top of the bolt and putting heatshrink on it.

Still not sure why there are holes through the board there - they look like mount holes... but only if used carefully.

Re: Mounting 0.4.3d using holes in PCB - earth question

Posted: Thu Feb 16, 2023 2:42 pm
by LPG2CV
Often, peeps slide them in on rails

Re: Mounting 0.4.3d using holes in PCB - earth question

Posted: Thu Feb 16, 2023 6:00 pm
by PSIG
pete12 wrote: Thu Feb 16, 2023 9:36 amStill not sure why there are holes through the board there
They are typically used through the matching holes in a Mega board to secure the Mega to the PCB, not to secure to a case. As LPG said, case slots are typically used for that. Most use zip-ties or nylon bolts to secure them together, or snap-in spacers/standoffs as mentioned here.

Re: Mounting 0.4.3d using holes in PCB - earth question

Posted: Fri Feb 17, 2023 8:21 am
by JHolland
pete12 wrote: Thu Feb 16, 2023 9:36 am Thanks - I ended up using non conductive washers and filing down the thread of the top of the bolt and putting heatshrink on it.
Still not sure why there are holes through the board there - they look like mount holes... but only if used carefully.

It wasn't uncommon with through-hole boards - an insulator kit was used, they come with a mica or heat conductive pad and a 'top-hat' nylon spacer:

https://www.ebay.com/itm/264405132013?h ... R9iQsufLYQ

Re: Mounting 0.4.3d using holes in PCB - earth question

Posted: Sun Dec 03, 2023 4:43 pm
by nicolas de los rios
i use a plastic block 5/16" and put screws to handle block to case and another to board handle in plastic