The following changes in requirements to the Standard for Safety Insulation Coordination Including Clearances and Creepage Distances for Electrical Equipment, UL 840, are being proposed: Surge Protective Devices Used in Electrical Equipment
ANSI/UL 840-2012 history
2012ANSI/UL 840-2012 Standard for Safety for Insulation Coordination Including Clearances and Creepage Distances for Electrical Equipment