flex size connecting multiple ovens

Are you sure it  is not enough ? Usually it is, the range of Zs for a far end fault for which the 2.5mmsq cable does not get too hot in the breaker trip time is quite wide.


For a period of 5 seconds or less, the relationship I²t = k²S² characterizes the time in seconds during which a conductor of c.s.a. S (in mm ²) can be allowed to carry a current I, before its temperature reaches a level which would damage the surrounding insulation.  so for 2,5mmsq, say 0.08  x 10^6, l say 80 000

allowable thermal stress for cables I²t (expressed in ampere² x second x 10⁶) so for a typical 40A breaker



so any fault less than about 4kA, and high enough to take out the breaker fast, say 5* 40A plus 10% for luck, say any fault current in the range from  250A to 4000A  will be just  fine for  full fault protection for a 2.5mm cable on a B40.

Are you sure it  is not enough ? Usually it is, the range of Zs for a far end fault for which the 2.5mmsq cable does not get too hot in the breaker trip time is quite wide.


For a period of 5 seconds or less, the relationship I²t = k²S² characterizes the time in seconds during which a conductor of c.s.a. S (in mm ²) can be allowed to carry a current I, before its temperature reaches a level which would damage the surrounding insulation.  so for 2,5mmsq, say 0.08  x 10^6, l say 80 000

allowable thermal stress for cables I²t (expressed in ampere² x second x 10⁶) so for a typical 40A breaker



so any fault less than about 4kA, and high enough to take out the breaker fast, say 5* 40A plus 10% for luck, say any fault current in the range from  250A to 4000A  will be just  fine for  full fault protection for a 2.5mm cable on a B40.