Spur direct from CU tripping RCD? Ask questions and find answers to many subjects relating to electrics and electrical work

[robinjon]

I recently connected a spur direct to my consumer unit. Reason was it was a simple back-to-back job through the wall to make an outdoor socket. Internal connection was via the 'sockets' circuit and to an approved, modern 'outdoor weatherproof socket. All connected smoothly.
Except that when I tried to use the socket, the rcb tripped. Is it possible to use a spur like this or must spurs come from a 'circuit'? Alternatively, does this reaction indicate a cable fault?
Any thoughts or suggestions gratefully received.

[Mr White]

When you say "you connected a spur directly to your consumers unit" what exactly did you connect it to?

(Pictures also help)

[ericmark]

[img]https://www.consumerunitworld.co.uk/ekmps/shops/consumer/resources/Design/inside-high-integrity-consumer-unit.jpg[/img]I hope the picture works, it shows 1/2/3 : (Three) Neutral Bars - the defining feature of a High Integrity Consumer Unit 4: Earth Bar.

The RCD works by comparing supply and return, if the same it will not trip, other wise it trips, likely you have selected wrong neutral bar, or if using RCBO's wrong trip for neutral.

[ericmark]

[attachment=0]inside-high-integrity-consumer-unit.jpg[/attachment]May be this will work better? it shows 1/2/3 : (Three) Neutral Bars - the defining feature of a High Integrity Consumer Unit 4: Earth Bar.

Wrong neutral bar and it will trip.

[robinjon]

Many thanks for your responses guys. Mr white - it was connected to the 'Socket Ground floor' circuit.

Ericmark - you were absolutely right. I wasn't even aware that there were different Neutral banks on a CU. anyway the problem is now sorted and everything is working as it I intended it should. Thanks again.

Robinjon