Recently I found a resistor broken on a PCB. It is a MOF type 1/2W through-hole resistor. I found that the resistor is directly placing (touching) on a PCB Live trace and I know that the potential difference between the resistor and the trace is about 220Vac. There is a small hole on the resistor and a burning mark on the PCB trace. Therefore I presume an electric arc was formed between the resistor and the PCB.
Then I read the safety standard EN60335-1. For the part describing creepage and clearance, it has a remark: "Lacquered conductors of windings are considered to be bare conductors" As I know common MOF resistor body is just a lacquered coating,
I would like to ask is this resistor considered as "Lacquered conductors of windings"? If so this is violate the safety standard.
If this is not, is a MOF through-hole resistor body touching a Live PCB trace violate the standard?
Appreciate if you can provide strong supporting document or information.
Thank you very much
Then I read the safety standard EN60335-1. For the part describing creepage and clearance, it has a remark: "Lacquered conductors of windings are considered to be bare conductors" As I know common MOF resistor body is just a lacquered coating,
I would like to ask is this resistor considered as "Lacquered conductors of windings"? If so this is violate the safety standard.
If this is not, is a MOF through-hole resistor body touching a Live PCB trace violate the standard?
Appreciate if you can provide strong supporting document or information.
Thank you very much
