It looks like a RCD, it feels like a RCD and it smells like a RCD. Crabtree BS4293.

Rather faded, but light green. 


It trips when the test button is pressed, but I can't fire it off with my Megger MFT1741. 


When these were being installed they were being tested by applying voltage without recording a trip time, rather than applying current and recording the trip time. 


So is expecting to test it as I would a modern RCD appropriate?


I have advised that replacement is required, being a 500 mA device in a domestic property, utter regardless of if I can get it to trip with a Megger MFT or not, but stand to be corrected if need be.


There is a Zs of around 12 ohms.


Andy Betteridge

Rather faded, but light green. 


It trips when the test button is pressed, but I can't fire it off with my Megger MFT1741. 


When these were being installed they were being tested by applying voltage without recording a trip time, rather than applying current and recording the trip time. 


So is expecting to test it as I would a modern RCD appropriate?


I have advised that replacement is required, being a 500 mA device in a domestic property, utter regardless of if I can get it to trip with a Megger MFT or not, but stand to be corrected if need be.


There is a Zs of around 12 ohms.


Andy Betteridge