Stacking relay boards


I have an application that is space limited
I need 32 relays in a small space

looks like the best way is 2 16 I2C relay boards, stacked on spacers
(yeah, access is limited, using pluggable connections, and my application is all low voltage)

Your documentation does not list height of the pcb, but does list min 0.25" to base

How tall is a PR16-5 boards, any recommendations?


Hi Jeff,

I think this is probably our smallest 16 channel relay controller:

The tallest component on that board would be the screw terminals which measure approximately 16mm from bottom of PCB to top of component.

If you have any other questions please let us know.
Thank you,
Travis Elliott

we are using the 3amp version of this board
We currently have the non pluggable board…looking to see if the pluggable will fit for the next order

Proposed setup:
stacking 2 boards from a chassis on standoffs…

16mm+16mm+ PCB thickness board 1
?mm airspace between boards
16mm+16mm+PCB thickness board 2
?mm airspace between bottom board2 and chassis

This look correct?

any recommends for airspace distances?

How about mechanical dimensions / datasheet on the pluggable connector please?


Hi Jeff,

Are you saying that you have DPDT relays on your board? That is the only 3 amp relays we carry. Just want to confirm that you actually have to have DPDT relays as that makes a very big difference on board height due to the double row screw terminals.

3amp DPDT

for DPDT, are pluggable connectors on both sides?
for SPDT, pluggable connectors on top side only?


That’s correct. DPDT relay controllers have one set of pluggable connectors which mount to the bottom side of the board, and there other set mounts to the top side of the board. I would highly recommend that you have a board in hand before you make any further design decisions as it is a bit odd.


well, I have a board in hand currently without pluggable cnnectors

how about some mechanical info on the pluggable connectors themselves?
That way I can make a decision before I buy the next 6 boards?


Hi Jeff,

Here is a photo of a DPDT board with pluggable connectors installed:

The height of those connectors are about 15mm. I would plan on at least 35mm overall for board head room.