Carbonzit, you are right,the UL,CSA ratings made no distinction between NO/NC contacts.The Omron MK3P-I actually has an inbuilt diode supression plus varistor surge suppression mechanism.
I think i have to make do with the omron relay,contactor is not necessary.
Breaks relatively large load currents despite small size.
Long life (minimum 100,000 electrical operations) assured by silver contacts.
Built-in operation indicator (Mechanical, LED), push button, diode surge suppression, varistor surge suppression.
Standard models are UL, CSA, SEV, DEMKO, NEMKO, SEMKO, TÜV (IEC), and VDE.
Conforming to CENELEC standards. **broken link removed**