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Safety Requirements on 120Vac Board

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by embedded_sys, Mar 6, 2018.

  1. embedded_sys

    embedded_sys Member

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    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?
     
  2. dknguyen

    dknguyen Well-Known Member

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    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?
     
    Last edited: Mar 6, 2018
  3. embedded_sys

    embedded_sys Member

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    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?
     

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