" 433.1 Every circuit shall be designed so that a small overload of long duration is unlikely to occur."
Basically we must design with some slack - a 32 A breaker will carry 32A all day, and perhaps nearly 40A for many hours.
A 13A fuse will carry 20A long enough to get the pins on a 13A plug to skin burning temperature.
We should not design in a way that tries to use this extra - so to deliberately put a 35A load on a 32A breaker may not trip, but it would break this rule, and it is not to be done.
There is a problem with sockets, as we have no control over what total load is plugged in, so instead the standard ring and radial configurations use recommended cable sizes that mean they are generally under-run even at the full load,except in some corner cases that luckily arise very rarely.
16A plugs do not need fusing, as they are only ever wired on 16 or 20A radials in 2.5mm2 or larger cable , so the protection at the origin is enough, and would not discriminate correctly if you added another 16A fuse or breaker at the load end.
" 433.1 Every circuit shall be designed so that a small overload of long duration is unlikely to occur."
Basically we must design with some slack - a 32 A breaker will carry 32A all day, and perhaps nearly 40A for many hours.
A 13A fuse will carry 20A long enough to get the pins on a 13A plug to skin burning temperature.
We should not design in a way that tries to use this extra - so to deliberately put a 35A load on a 32A breaker may not trip, but it would break this rule, and it is not to be done.
There is a problem with sockets, as we have no control over what total load is plugged in, so instead the standard ring and radial configurations use recommended cable sizes that mean they are generally under-run even at the full load,except in some corner cases that luckily arise very rarely.
16A plugs do not need fusing, as they are only ever wired on 16 or 20A radials in 2.5mm2 or larger cable , so the protection at the origin is enough, and would not discriminate correctly if you added another 16A fuse or breaker at the load end.
