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I'm trying to work up an estimate for quantities of cable on a forthcoming project:
For a ring socket circuit, I have made a conservative estimate of 73m circuit length. This is basically the perimeter of 4 rooms and a hallway, from the CU back to the CU.
The area of the ground floor is about 70 sq. m.
There will be 15 sockets in total on the circuit
Table 8A of the OSG indicates by floor area that 2.5 sq mm is the minimum CSA of conductor, and that a 30A or 32A MCB is required. Am I correct so far?
The cable will be routed under a suspended floor and occasionally chased through plaster/brick. There will be no runs through thermal insulation.
What correction factors, if any, might reasonably apply in this case? under what circumstances should cable larger than 2.5 sq mm be chosen?
If I was dealing with a fixed appliance I would be considerably more at ease because I would then have more definite design constraints. Is there a "rule of thumb" for ring sockets? something like "allow for 100W per socket worst-case" would be handy.
For a ring socket circuit, I have made a conservative estimate of 73m circuit length. This is basically the perimeter of 4 rooms and a hallway, from the CU back to the CU.
The area of the ground floor is about 70 sq. m.
There will be 15 sockets in total on the circuit
Table 8A of the OSG indicates by floor area that 2.5 sq mm is the minimum CSA of conductor, and that a 30A or 32A MCB is required. Am I correct so far?
The cable will be routed under a suspended floor and occasionally chased through plaster/brick. There will be no runs through thermal insulation.
What correction factors, if any, might reasonably apply in this case? under what circumstances should cable larger than 2.5 sq mm be chosen?
If I was dealing with a fixed appliance I would be considerably more at ease because I would then have more definite design constraints. Is there a "rule of thumb" for ring sockets? something like "allow for 100W per socket worst-case" would be handy.