I tend to feel that cooker circuits as they are recommended to be installed (6mm² on B32A) are one of the least safe circuits, because of the designed in overload, even if only for a short time.
However practical experience over many years shows that this is a generally a safe installation, terminal overheats aside.
This is because the operation of a cooker is such that it is practically very unlikely in domestic use to be able to cause any long term problem. I think HHD did describe s student let where the hob was used continuously for heating many pans of water for a bath as the immersion was not working, but this must be the exception.
I did some rather rough calculations on current draw in high use (14kW all switched on simultaneously) and found that the limits of the cable were exceed only for very short periods of time (5 mins) in the initial instance and that as time went on the cable was never overloaded and the circuit breaker was never closer than 15mins away from tripping.
The thermal cycling of the elements means that so long as the cooker is not being misused or the thermostats have not broken (which would lead to more rapid problems much faster than melting the cable) that the circuit will work without deterioration (even on Christmas day) since the current ratings are for 24 hour continuous loading 5 mins will reduce the life of the cable slightly over time but probably no more than a hot summer may do to the rest of the cables installed near the limits of their CCC.
However practical experience over many years shows that this is a generally a safe installation, terminal overheats aside.
This is because the operation of a cooker is such that it is practically very unlikely in domestic use to be able to cause any long term problem. I think HHD did describe s student let where the hob was used continuously for heating many pans of water for a bath as the immersion was not working, but this must be the exception.
I did some rather rough calculations on current draw in high use (14kW all switched on simultaneously) and found that the limits of the cable were exceed only for very short periods of time (5 mins) in the initial instance and that as time went on the cable was never overloaded and the circuit breaker was never closer than 15mins away from tripping.
The thermal cycling of the elements means that so long as the cooker is not being misused or the thermostats have not broken (which would lead to more rapid problems much faster than melting the cable) that the circuit will work without deterioration (even on Christmas day) since the current ratings are for 24 hour continuous loading 5 mins will reduce the life of the cable slightly over time but probably no more than a hot summer may do to the rest of the cables installed near the limits of their CCC.
