Chet Kincaid wrote:

DC is more problematic to switch than AC and a switch or relay designed for
AC must be derated (often massively) to use with DC.

But what about the reverse?

I have an automotive type relay rated 40A at 14V.

That should handle 10A (actually less) at 120VAC okay, yes?


** As far as the contacts are concerned, you are probably correct.

But relays have another job which is to safely isolate the coil connections from the switched circuit.

There is no guarantee that a relay specified for use in an automotive, 12V DC environment is suitably insulated for connection to the AC supply - where spike voltages in the thousands occur.


..... Phil