EadF wrote:I got one more "advantage of relay" point:
Sometimes SSRs fails to turn off (https://www.ia.omron.com/support/faq/an ... index.html)
This can happend for a number of reasons, but i've noticed it happend if the SSR and the load are greatly unbalanced.
(In my case a 25A SSR driving a 40W light bulb)
Misfire in case of SSR it's a different story.
And yes, might happen, and yes, can be avoided, depending on your setup and the type of load, resistive, inductive or mixed. In the real world it's a place for every choice available: Triac, SSR, Power Thyristor, Relay, Manual switch, etc.
It really depends on what specific application you want to use them. For MAINS power switching mostly used solutions today are Solid State based ones.
If somebody want to use a relay...of course can be used.
But WHY?