if you have a look in onsite guide (amendment 1)
100m is the recomended max length for a 2.5 ring feeding sockets.
also mentions 50m for lights if i remember correctly, havent used onsite guide for a while
Okay guys, we need to put this one to bed.
It's not "100m is the
max length for a 2.5 ring feeding sockets." It's Maximum
FLOOR AREA per 100 square metres. In the BGB they clearly state that "Historically, a limit of 100 square metres has been adopted". This is where the "ring final circuit starts and finishes at the distribution board, where it is connected to a 30A or 32A overcurrent protective device".
It is clearly a recommendation (historical). 433.1.103.
This can be achieved by:
(i) locating so's to provide reasonable sharing of the load around the ring.
(ii) not supplying immersion heaters, comprehensive electric space heating or loads of a similar profile from the ring circuit.
(iii) connecting cookers, ovens and hobs with a rated power exceeding 2 kW on their own dedicated radial circuit.
(iv) taking account of the
total floor area being served. (historically , a limit of 100m squared).
And it's not 50m length for lights - It's, for a Radial final circuit with a 20A protective device in 2.5mm (historically the
floor area served is limited to 50m squared)
And for a Radial final circuit with a 30A or 32A protective device in 4mm (historically the
floor area served has been limited to 75m squared.
I probably muddied the waters with my tongue in cheek comment that "mr diy would come along and uprate the breaker" This was meant as a throw-away quip - but obviously some peeps have taken it as verbatim. For that I apologise. I'll be more careful in future with my attempts at comedy.
I ought to add that the above quoted Regs are not aimed at the many regulars on here who are familiar with them - But those who may not have updated may find them helpful.
Ok, I'll put my tin hat on.
