SRCDs are intended for use in circuits where the fault protection and additional protection an RCD are already assured upstream upstream of the SRCD .
so, pointless, unless you require to play the chance of failure game, and cascade 2 devices with poor failure rates, to have a system over all with a reasonable one.
So if say the change of wither the 1st RCD or the second failing to trip is perhaps 5%, the chance of both failing, so long as the failure mechanisms are independent is 0.25%.
SRCDs are intended for use in circuits where the fault protection and additional protection an RCD are already assured upstream upstream of the SRCD .
so, pointless, unless you require to play the chance of failure game, and cascade 2 devices with poor failure rates, to have a system over all with a reasonable one.
So if say the change of wither the 1st RCD or the second failing to trip is perhaps 5%, the chance of both failing, so long as the failure mechanisms are independent is 0.25%.
