The goal is to control 18 devices by using rocker switches with LED. The total ampere can be up to 25A.
The PCB size is 150mm x 250mm. The configuration is FR-4 with 2 oz/ft^2 copper. The bottom layer is GND plane where the top layer is 12V plane.
What are used:
12v 350w power supply unit
Multiple 6P Barrier Terminal Blocks
18 PTC resettable fuses
18 12v-led-rocker switches
Is this setup safe for such current flow? Is there any potential hazard with this configuration? What can be done to improve the design?
MarkT
December 7, 2019, 11:33am
2
Firstly don't use thermal reliefs on high current traces - you want lots of copper to carry the current to the pad.
It looks like you can double the width of the traces easily, so why not do it? I know 2oz copper is going to help, but the copper's there to be used.
Thirdly are those fuses physically big enough? If each load is about 1.5A I'd expect the fuses to dissipate a fair bit.
Lastly add four mounting holes at/near the corners
MarkT:
It looks like you can double the width of the traces easily, so why not do it? I know 2oz copper is going to help, but the copper's there to be used.
Thirdly are those fuses physically big enough? If each load is about 1.5A I'd expect the fuses to dissipate a fair bit.
Lastly add four mounting holes at/near the corners
Thanks for the suggestions. Bigger trace width is a good idea. The fuse I use is "SMD1812P200TF16" which I hold is 2A and I trip is 4A: https://datasheet.lcsc.com/szlcsc/1809211111_RUILON-Shenzhen-Ruilongyuan-Elec-SMD1812P200TF16_C20812.pdf
Do you really want to be bothered with SMD fuses and then hand soldering the switches and terminals?
How many of these are you building? If you’re having them built, I would expect the added cost of reflow plus hand soldering would more than offset the part cost difference.
