Hi All,

I'm a newbie here. I'm currently working on a device that controls 220V AC equipments via an electromechanical relay. The relay and the low voltage electronics are all housed in one enclosure. The connections between my electronics and the relay are VCC, GND and CONTROL line for turning on/off the relay. In this setup, how can I protect my electronics from the AC voltage in cases like there is a faulty relay or that the AC wiring is shorted with the VCC, GND or CONTROL lines? Thanks!

 

You could a transient voltage suppressor and a fast fuse https://www.vishay.com/docs/88301/15ke.pdf
The switch on time is 10microsec this indicates that your mcu power supply should carry an input filter able to handle the first 10 micro sec's
But I can not give a proper solution without schematic's and mechanical layout's.

Picbuster

 

Use correct wiring techniques and components, relay etc, that have the correct insulation rating.
Keep all LV and AC wiring dressed appropriately.
This is done all the time in industrial installations and systems.
If in N.A. obtain a copy of NFPA79.
Max.