Wiring up a new conservatory (again)

[Richard C]

My new conservatory company’s electrician is wiring into the downstairs ring main rather than run a separate 20A radial circuit from a spare way on my new C/U - a route that was suggested to me by someone else.

OK, but rather than break into the ring main under the floorboards using a junction box he has connected into the circuit inside an existing double 13A socket using taped terminal blocks; is this acceptable?

 

[dingbat]

Provided he is correctly extending the ring, that method is better than acceptable; it's recommended. JBs under floorboards are regarded as inaccessible for inspection.

 

[Richard C]

Provided he is correctly extending the ring, that method is better than acceptable; it's recommended.

Must confess I am little surprised but thanks very much for putting me straight.

 

[dingbat]

The socket back box is a properly rated enclosure for electrical terminations and it is both accessible and visible. Terminal blocks are an approved method of joining cables, provided they are enclosed. If a problem occurred in the future, the connections could be readily inspected. This method complies in all respects with the regulations.

A Junction box under the floor is not visible and its location would not be known to future occupants of the house unless a hatch was provided and suitably marked, which most people would not find acceptable. Also what happens if, say, laminate flooring is put down? Or ceramic tiles?