DIY Doctor UK DIY Forums

Please does any wiring run inside a stud wall have to be in a conduit?

No
Although there is special cable designed for stud walls which does not require RCD protection and also using conduit would also allow the non use of RCD's.
The rules with RCD use is new and most wiring in stud walls will be twin and earth.

Under the 17th edition wiring regulations wiring in stud walls if less than 50mm deep must be protected by a 30 milliamp rcd
regards
Topspark