gkenyon:

Wouldn't this provide electrical separation to more than one item of equipment if used on a caravan or mobile/transportable unit?


I'm not a big fan of that idea, especially as the RCD test will actually introduce a fault ... and I may be in contact with exposed-conductive-parts at the same time ... for example when resetting the RCD in a transportable unit with metal CU !


I think I'd prefer to simply connect the caravan or unit to a socket-outlet with additional protection by 30 mA RCD in accordance with Regulation 411.3.3 or 708.415, and conduct the "up/down" test on the RCD in the caravan or mobile/transportable unit !

 Yes, you're right, there is not an easy cheat to avoid dismantling the caravan installation for some testing by at least opening up the consumer unit within the caravan, even for something as simple as testing the RCD inside the caravan with a RCD tester of any type without tripping an upfront site installation RCD.


I have been trying to figure out the wiring arrangement within that Seaward PAT RCD isolation transformer test adapter and ended up back at square one with an CPC to neutral link inside it, the conclusion I came to is that with an isolation transformer is that you don't need RCD protection downstream of it and you have got to tweak the wiring arrangement to reintroduce an "earth" connection to fire the RCD off, so it's no longer an isolation transformer. 


Andy Betteridge.

gkenyon:

Wouldn't this provide electrical separation to more than one item of equipment if used on a caravan or mobile/transportable unit?


I'm not a big fan of that idea, especially as the RCD test will actually introduce a fault ... and I may be in contact with exposed-conductive-parts at the same time ... for example when resetting the RCD in a transportable unit with metal CU !


I think I'd prefer to simply connect the caravan or unit to a socket-outlet with additional protection by 30 mA RCD in accordance with Regulation 411.3.3 or 708.415, and conduct the "up/down" test on the RCD in the caravan or mobile/transportable unit !

 Yes, you're right, there is not an easy cheat to avoid dismantling the caravan installation for some testing by at least opening up the consumer unit within the caravan, even for something as simple as testing the RCD inside the caravan with a RCD tester of any type without tripping an upfront site installation RCD.


I have been trying to figure out the wiring arrangement within that Seaward PAT RCD isolation transformer test adapter and ended up back at square one with an CPC to neutral link inside it, the conclusion I came to is that with an isolation transformer is that you don't need RCD protection downstream of it and you have got to tweak the wiring arrangement to reintroduce an "earth" connection to fire the RCD off, so it's no longer an isolation transformer. 


Andy Betteridge.