Tender For supply of class "b" and "c" surge protection device (spd) type i & ii with visual indication and potential free contact to remote monitoring as per rdso spec no. rdso/spn/165/2012 version 3.0 or latest and iec standard 61643 for signals line 230vac application with handling lightning surges of 8/20 microseconds. one set consists of 3 nos. of spd (two nos. of b class (l-n,l-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. make- obo/phoenix/betterman/dehn or similar. [ warranty period: 30 months after the date of delivery ]