A recent EICR turned up a fault: an RCD fused spur was feeding a socket and a shower pump, and neither socket or pump had continuity on the CPC. The circuit was also showing low IR between live conductors and earth (0.09 Mohms).
I came to do the remedial work and found the reason for the faults: the RCD spur. Nothing unusual about the front, but the back is interesting. There are 2 separate earth terminals, one labelled 'E', and the other labelled 'SE' (an IR test between these 2 earth terminals confirms that they are totally separate). There is a red insulated conductor connected to the SE terminal, which disappears into the body of the unit.
The feed to the spur had its CPC terminated in 'E', while the outgoing cables to the socket and pump had their CPCs terminated in 'SE'. At the time of the inspection I was able to test the RCD through the socket, giving a fairly normal time of 33ms.
I removed the RCD spur and replaced with a normal fused spur (circuit is now RCBO'd), and in addition to sorting the continuity on the CPCs, it also eliminated the low IR problem too.
Has anyone ever come across one of these, or know any more about them? My first thoughts were that it was a dodgy ebay item, however an internet search suggests that it may be an old volex unit.
![[ElectriciansForums.net] Unusual RCD fused spur](https://www.electriciansforums.net/attachments/rcdspurfront-jpg.105664/ "[ElectriciansForums.net] Unusual RCD fused spur")
![[ElectriciansForums.net] Unusual RCD fused spur](https://www.electriciansforums.net/attachments/rcdspurback-jpg.105663/ "[ElectriciansForums.net] Unusual RCD fused spur")
I came to do the remedial work and found the reason for the faults: the RCD spur. Nothing unusual about the front, but the back is interesting. There are 2 separate earth terminals, one labelled 'E', and the other labelled 'SE' (an IR test between these 2 earth terminals confirms that they are totally separate). There is a red insulated conductor connected to the SE terminal, which disappears into the body of the unit.
The feed to the spur had its CPC terminated in 'E', while the outgoing cables to the socket and pump had their CPCs terminated in 'SE'. At the time of the inspection I was able to test the RCD through the socket, giving a fairly normal time of 33ms.
I removed the RCD spur and replaced with a normal fused spur (circuit is now RCBO'd), and in addition to sorting the continuity on the CPCs, it also eliminated the low IR problem too.
Has anyone ever come across one of these, or know any more about them? My first thoughts were that it was a dodgy ebay item, however an internet search suggests that it may be an old volex unit.
