Wire-to-board / Board-to-board power connectors

Hey there! I’d like some suggestions about connectors for a power supply I’m designing.
I’m not used to much else than terminal blocks, pin headers, jst…

My idea was creating a power supply pcb module, with it’s own transformer.
Transformer primary (230V) will go to a connector, from there

  1. it can go to the mains board
  2. alternatively to another power supply pcb module, exactly the same of the first one and stacked above the first one. From this second board it would go to the mains board.

So basically I need a connector that can be used both for wire-to-board and board-to-board connection, capable of 250V few hundreds mA

Not a great idea.
Safety is a prime consideration when dealing with mains. Using your system means it is POSSIBLE that there will be exposed pins at mains potential either on one board or on the end of a joining lead.

If you must have connectors from the mains board to one or two modules, you should have two female connectors on the mains board and a male connector on each power PCB module and then have two leads, both with a male and female end so you can connect one or the other or both without the possibility of touching live pins.

Don’t forget, no matter how much you take care, others may be ignorant of your project.

Personally, I’d have one larger transformer mounted with the mains board in a secure Ventilated/un-ventilated box way out of harms way then attach the secondary to two outputs for connection to your power supply modules.


I think terminal blocks would be a standard here. Even PCBs are stacked you can use wire to connect their terminal blocks. Safety standards put some extra needs on mains connections.
Nowadays it seems safer, easier, using less space and cheaper to use ready power supply from cellphone or laptop instead of transformer.


It will be a power supply for guitar effects (it will actually have more than two outputs) and I want it to have isolated outputs, so I’ll use multiple little transformers with 2 secondaries

You also have the option to just put two different connectors in parallel in the schematic and on the PCB. If you intend to use only one of the two options, then the footprints can overlap and this reduces the amount of space needed.

Just using two (correct) footprints is probably better then using some “compromise” footprint that fits neither option particularly well.

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I think no.
As I understood OP wants to connect them together by something like pin-headers and then wires to one of them. So that one with wires connected to it needs both options at once.

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At this point I will evaluate if:

a. making a single pcb
b. using terminal blocks as you suggest (the original idea was to make modules, because most of them are identical and I would save something from services like JLC)

I don’t know how JLC values your order but if limiting number of PCBs ordered is important you can make one pcb containing many pcbs.
Some time ago I have ordered one PCB and here is less than 1/4 of it:

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So this is what I’ve done so far…

Any suggestions?
Is AC tracks clearance enough?

Is there a particular reason why you have put the fuses on the secondary side?
Is there an external fuse in the mains supply line, not located on the PCB?
My thought would be to place one primary fuse for each transformer, in order to protect against any possible problems in the transformer itself, in addition to overload / short circuit on the secondary side.
Also, any particular reason for so many primary input connections?

I would increase the isolation distance between primary and secondary side. The transformers are large and give plenty of opportunity for healthy isolation distances. For example, keep primary and secondary components on their respective sides of the transformers (“top” and “bottom” in the picture), and nothing on the left and right.

Those were my first thoughts.

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You are right, these fuses are there to protect secondaries, but it needs primary protection too. I was going to put a single panel mounted fuse but maybe that’s not a good idea?

The primary connection that goes to mains (actually switch, primary fuse, etc) is the central one.
The others are there to expand the PS with other modules that would be stacked above the main board. Actually they can be reduced if for example I decide to create a single additional PCB module.

BTW, I was hoping to use a Hammond 1441-16BK3, which is 254x152x51mm, so I was trying to keep the board size to a minimum (currently it’s 258x116)

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