flex size connecting multiple ovens

One additional limitation - in UK style T and E the earth core is not insulated, and it 'only' damages the the jacket rather than carbonising the functional insulation in contact with  a live core when it gets hot.

Now, as shown above, the reduced CPC is fine for a B40 MCB anyway except for the sort of fault current you won't get unless you live next to the substation and the cooker cable is very short, even if you are at near the full 6KA PSSC at the MCB end- , but to be always OK, the use of a reduced size cpc relative to live is based on the CPC not  being pre-heated by the load current in the way the L and N might be, so the initial temperature for PVC is never starting at the full 70c (though in well lagged environments it will only be 5 to 10 degrees below the current carrying cores ), and the plastic around it is not considered to be so valuable as proper insulation.

There is a reason that in those countries that have now decided to insulate their CPCs in their T and E like cables, Ireland and New Zealand come to mind as having abandoned bare earths since 2000, they have at the same time  included a requirement for the copper cross-section of the CPC to be now equal to that of the live.


And in any case a larger CPC is good in TNx systems also because it helps reduce the touch voltage that occurs during the short time that ADS is operating.

One additional limitation - in UK style T and E the earth core is not insulated, and it 'only' damages the the jacket rather than carbonising the functional insulation in contact with  a live core when it gets hot.

Now, as shown above, the reduced CPC is fine for a B40 MCB anyway except for the sort of fault current you won't get unless you live next to the substation and the cooker cable is very short, even if you are at near the full 6KA PSSC at the MCB end- , but to be always OK, the use of a reduced size cpc relative to live is based on the CPC not  being pre-heated by the load current in the way the L and N might be, so the initial temperature for PVC is never starting at the full 70c (though in well lagged environments it will only be 5 to 10 degrees below the current carrying cores ), and the plastic around it is not considered to be so valuable as proper insulation.

There is a reason that in those countries that have now decided to insulate their CPCs in their T and E like cables, Ireland and New Zealand come to mind as having abandoned bare earths since 2000, they have at the same time  included a requirement for the copper cross-section of the CPC to be now equal to that of the live.


And in any case a larger CPC is good in TNx systems also because it helps reduce the touch voltage that occurs during the short time that ADS is operating.