supply of supply of class b&c surge protection device (spd) .supply of class b&c surge protection device (spd) .,supply of class b&c surge protection device (spd) type i & ii with visual indication and poten tial free contract to remote monitoring as per rdso spec no. rdso/spn/165/2012 version 3.0 or latest and iec standard 61643 for signals line 230 v ac application with handling lightning surges of 10/350 microseconds and switching surges of 8/20 microseconds. one set consists of 3 nos of spd (two nos of b c lass (l n, n-e) and one no of c class (l-n) all enclosed in a box with kema or vde certified as per latest iec 61643-11-2011 standard class b&c surge protection device required with three modules only.make/brand - phoenix contact or similar and reputed make. [ warranty period: 12 months after the date of delivery ] ]