Safety Requirements on 120Vac Board

[embedded_sys]

I've designed a board with a few relays that switch 120VAC. I have the normally open side of the relay connected to a current limiting resistor and opto-isolator. Do I need to worry about single fault failure for safety testing? If so, can I just put two resistors in series?

 

[dknguyen]

By safety testing, you mean official certification?

Doesnt the current limiting resistor interfere with function? If it doesnt, isnt it too low to be protective?

 

[embedded_sys]

Yes I mean official certification. I'm not exactly sure what you mean by 'interfere with function'. For certification, will I need to worry about single fault failure?