Help working out complicated "floor area" for radi

[jpw999]

Hi, Sorry but cannot find a specific ref to my query so can you please help. I know that a room say 3 x 3 mtr is a floor area of 9 square metres...BUT... how do I work out a floor area of a say a route that goes from c/u up wall and along the loft and then down a wall (for a radial) or indeed for ring to come back up the wall the same route back to the c/u?
OR.. does floor area mean just final destination location ignoring the loft and up/down wall part of getting there?
I can work out cable length simply by measure - but this floor area bit is confusing.
I have seen refs to the WHY floor area is to be known - eg heating required for that space. Therefore, I cannot see why a loft or wall should come into the equasion if the final destination is a small 3 x3 metre room.
Hope a spark can enlighten.
Thank you.

 

[flameport]

Floor area is the total area of the room or rooms which the sockets on a particular circuit are in.
e.g a radial circuit supplies socket outlets in two rooms, the first room is 3x3m, the second room is 2x3m. Total floor area = 15 square m.

However the limits for ring and radial circuits are not regulations, and are only intended as a guide. They were based on typical loadings for a domestic property, the idea being that if the floor area is more than the limit, it is likely that two or more circuits would be required to accomodate the total load.

In practice it is likely other limits such as volt drop will be met before the floor area is an issue.
The expected loading of the circuit should be considered - in a house, a ring final for two downstairs rooms and a kitchen would typically have a much higher average load than the same circuit supplying three bedrooms, even though the floor area would be similar.

 

[Goldberg]

Hope a spark can enlighten.

Of course, but if it's in a special location then it's notifiable.

 

[jpw999]

Many thanks - I could not have explained it better myself (even if i had known the answer lol)
Appreciate the extra info regarding a second room added to the equasion.

So from that, if i was foolish enough to add a socket in the loft on the way to the 3 x 3 , I would have to add the loft dimension as well ...I seeee.

Where there was darkness now there is light.

Cheers.
Jim.
P.S. Appreciated the added humour.