extension re wire, with 15 way wylex consumer unit to 17th edition.
circuits
RCD A
1. 32amp upstairs sockets (original)
2. 32 amp cooker socket (new)
3. Kitchen sockets (new)
4, 20 amp boiler socket (original)
5. 6 amp downstairs lights (original)
6. Upstairs lights (original)
RCD B
1.32amp living room sockets (new)
2. 32 amp downstairs sockets (original)
3 32amp upstairs sockets (new)
5. 6amp upstairs light (new)
6. 6 amp outside lights (new)
7. 6 amp kitchen lights (new)
2 x RCBO's
one for smoke detectors
one for new large fridge freezer.
no appliances connected.
All dead circuit checks carried out on new and old. Continuity of all circuits correct. Polarity correct. And insulation readings correct. New main earthing throughout. New consumer unit wired up, as above. Customer wished all circuits to be separated as described to identify new from old in the future.
Ready for live testing. Energised all of RCD A circuits, energised all of RCD B circuits. RCD A tripped. RCD B stayed energised, however the 2 lighting circuits (6 and 7) when energised would trip RCD A. Tests on RCD A proved that it was defective so this was changed the next day. New RCD fitted to section A, and random tripping would occur on RCD A regardless of which sequence of breakers would be on, on section A or B. RCD B would still be on with no problems. All breakers switched off on RCD A, and RCD B all made, RCD A would trip again when 6 and 7 on b were made. The main neutral terminal to RCD A neutral busbar was disconnected. Polarity checks were now carried out between incoming live, and earth (240 volts), incoming live and RCD B busbar (240 volts), incoming live and RCD A disconnected and isolated busbar (240 volts). Since all circuits to RCD A neutral busbar were isolated from the maiin neutral terminal of the RCD A, I could not understand how this provided a potential difference. I disconnected all the circuits again from this busbar, re-did insulation readings between earth and neutral on RCD A. All circuits were in excess of 299 megs, apart from the new kitchen circuit which read 0 megs on one of the ring main neutrals, the other being 299 megs. I surmised that there was a direct short between one neutral and the earth, but could not understand why it was not recognised on the second. Since disconnecting the kitchen circuit and neutrals, RCD A has remained energised and everything is working. what is more annoying is that the fault has gone.
Can somebody please explain to me why making a breakers on RCD B will trip RCD A. I am happy that I have identified the correct circuit causing the problem. If you can follow this, you need a good stiff drink. Much obliged.
circuits
RCD A
1. 32amp upstairs sockets (original)
2. 32 amp cooker socket (new)
3. Kitchen sockets (new)
4, 20 amp boiler socket (original)
5. 6 amp downstairs lights (original)
6. Upstairs lights (original)
RCD B
1.32amp living room sockets (new)
2. 32 amp downstairs sockets (original)
3 32amp upstairs sockets (new)
5. 6amp upstairs light (new)
6. 6 amp outside lights (new)
7. 6 amp kitchen lights (new)
2 x RCBO's
one for smoke detectors
one for new large fridge freezer.
no appliances connected.
All dead circuit checks carried out on new and old. Continuity of all circuits correct. Polarity correct. And insulation readings correct. New main earthing throughout. New consumer unit wired up, as above. Customer wished all circuits to be separated as described to identify new from old in the future.
Ready for live testing. Energised all of RCD A circuits, energised all of RCD B circuits. RCD A tripped. RCD B stayed energised, however the 2 lighting circuits (6 and 7) when energised would trip RCD A. Tests on RCD A proved that it was defective so this was changed the next day. New RCD fitted to section A, and random tripping would occur on RCD A regardless of which sequence of breakers would be on, on section A or B. RCD B would still be on with no problems. All breakers switched off on RCD A, and RCD B all made, RCD A would trip again when 6 and 7 on b were made. The main neutral terminal to RCD A neutral busbar was disconnected. Polarity checks were now carried out between incoming live, and earth (240 volts), incoming live and RCD B busbar (240 volts), incoming live and RCD A disconnected and isolated busbar (240 volts). Since all circuits to RCD A neutral busbar were isolated from the maiin neutral terminal of the RCD A, I could not understand how this provided a potential difference. I disconnected all the circuits again from this busbar, re-did insulation readings between earth and neutral on RCD A. All circuits were in excess of 299 megs, apart from the new kitchen circuit which read 0 megs on one of the ring main neutrals, the other being 299 megs. I surmised that there was a direct short between one neutral and the earth, but could not understand why it was not recognised on the second. Since disconnecting the kitchen circuit and neutrals, RCD A has remained energised and everything is working. what is more annoying is that the fault has gone.
Can somebody please explain to me why making a breakers on RCD B will trip RCD A. I am happy that I have identified the correct circuit causing the problem. If you can follow this, you need a good stiff drink. Much obliged.
