Hi,
I'm new to the site and hopefully someone will be able to help. I've recently purchased a property and wanted to sort out the garden electrics. I was a qualified electrician before I retired. There was already SWA cable installed around the garden supporting lights and sockets for two sheds, two pond pumps and two UV filters. The feed was taken directly from a 13A spur from the dwelling ring final circuit. All lights, sockets, pumps, UV filter and any attached devices were working fine.
I decided to install a small garage consumer unit in my shed to run the aforementioned services. I bought the CU from Screwfix. The RCD is rated a 40A 30ma and has two MCB's - 6A and 32A.
I've reconnected the existing SWA cable feeds to the CU. The feed to the CU is still from the switched 13A spur from the dwelling ring final circuit.
As soon as I switch on the MCB for each circuit, for either the lights or sockets, it trips out the RCD. The RCD doesn't trip until I switch on the MCB's. One device does work without tripping the RCD which is an aerator pump used in the pond. I've connected the pumps directly to the dwelling's ring final circuit and they don't trip the dwelling RCD. I've checked the L-E, N-E and L-N impedance, using a multimeter, and they are over 500Mohms. I haven't used a megger yet to test the resistances as I don't have one now.
Hope I've made sense but any advice would be greatly appreciated.
Regards,
Chris
I'm new to the site and hopefully someone will be able to help. I've recently purchased a property and wanted to sort out the garden electrics. I was a qualified electrician before I retired. There was already SWA cable installed around the garden supporting lights and sockets for two sheds, two pond pumps and two UV filters. The feed was taken directly from a 13A spur from the dwelling ring final circuit. All lights, sockets, pumps, UV filter and any attached devices were working fine.
I decided to install a small garage consumer unit in my shed to run the aforementioned services. I bought the CU from Screwfix. The RCD is rated a 40A 30ma and has two MCB's - 6A and 32A.
I've reconnected the existing SWA cable feeds to the CU. The feed to the CU is still from the switched 13A spur from the dwelling ring final circuit.
As soon as I switch on the MCB for each circuit, for either the lights or sockets, it trips out the RCD. The RCD doesn't trip until I switch on the MCB's. One device does work without tripping the RCD which is an aerator pump used in the pond. I've connected the pumps directly to the dwelling's ring final circuit and they don't trip the dwelling RCD. I've checked the L-E, N-E and L-N impedance, using a multimeter, and they are over 500Mohms. I haven't used a megger yet to test the resistances as I don't have one now.
Hope I've made sense but any advice would be greatly appreciated.
Regards,
Chris