EN 61 558 IEC 61558. ENEC, UL recognised. To conform to VDE 0550,UL506 all transformers with 2 x 24V outputs should not have their secondaries connected in series.. PCB Mount 230Vac Primary VC/VCM Series. Single and twin secondary windings for series or parallel connection Vacuum resin moulded to UL94-V0 rating Low inter-winding capacitance Low radiated noise 100% electrical and flash tested Extra fixing points for secure board mounting (25 VA and 36 VA)