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I am trying to design a PCB with AC mains which is going to be controlled using relays to turn on fans and heater. I have never designed PCB for AC. What should I look out for and what should I be doing when designing for it?

JYelton
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Divvv
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  • I would advise you to download some open source Arduino mains voltage relay board designs and board layouts and browse through those/modify to suit your needs. – DSI Mar 06 '20 at 00:29
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    Without knowing your exact requirements it is difficult to advise in detail as different safety safety standards apply in different markets and Creepage / Clearance requirements vary depending on PCB material and operating conditions. Otherwise the answer from @hacktasical as covered the basics. – Warren Hill Mar 06 '20 at 01:21

1 Answers1

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When working with line voltage there's some key points that come up:

  • Insulation / isolation between mains and low-voltage
  • Creepage / clearance on the board
  • Fire retardant materials (that's where the 'FR' in FR2 comes from)
  • Safety approved components

The main standards for the board that apply are:

  • IPC-2221A, "Generic Standard on Printed Board Circuit"
  • IEC-60950-1 (EU and many others)
  • UL 60950-1 (USA, generally harmonizes with IEC-60950-1)

Some more info:

https://resources.altium.com/pcb-design-blog/high-voltage-pcb-design-creepage-and-clearance-distance

And, there is a new standard replacing IEC-60950-1, which uses hazards-based methodology, called IEC-62368-1. This takes effect on Dec. 20 2020.

More here: https://www.cui.com/blog/the-latest-on-iec-62368-1

hacktastical
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