rating of flexible cables in a none mobile situation e.g. the venerable inbuilt/fixed [induction] hob install

psychicwarrior said:

, why ? 

Because of Table 42.1, flexible cable is (generally) expected to be hand-held in BS 7671.

psychicwarrior said:

and  is it  'compliant with regs' to diddle it up to a CCA based on 70 degrees, in such a 'fixed' hob/oven install (or any fixed install for that matter)

If it's fixed and generally not intended to be touched, I see no real problem purely based on current-carrying capacity as a mental exercise.

However, with heating appliances I think it's worth remembering that heat can be conducted away from the appliance through the copper ... and if there's only a short lead, you'd perhaps need to think whether, running the cable for a conductor temperature (with no external influences) at 70, if there was a risk of the conductor temperature exceeding 70 deg C at the plug  or connection unit.

And also consider whether, under/behind the hob (or over) is the ambient temperature really limited to the 30 deg C as assumed by Tables 4F1A, 4F1B, 4F3A and 4F3B?

psychicwarrior said:

, why ? 

Because of Table 42.1, flexible cable is (generally) expected to be hand-held in BS 7671.

psychicwarrior said:

and  is it  'compliant with regs' to diddle it up to a CCA based on 70 degrees, in such a 'fixed' hob/oven install (or any fixed install for that matter)

If it's fixed and generally not intended to be touched, I see no real problem purely based on current-carrying capacity as a mental exercise.

However, with heating appliances I think it's worth remembering that heat can be conducted away from the appliance through the copper ... and if there's only a short lead, you'd perhaps need to think whether, running the cable for a conductor temperature (with no external influences) at 70, if there was a risk of the conductor temperature exceeding 70 deg C at the plug  or connection unit.

And also consider whether, under/behind the hob (or over) is the ambient temperature really limited to the 30 deg C as assumed by Tables 4F1A, 4F1B, 4F3A and 4F3B?

Thank you GKenyon

"Because of Table 42.1, flexible cable is (generally) expected to be hand-held in BS 7671."

Is it generally/preferably/expected too, to be used as a connection between a [fixed in the scenario case] hob and outlet plate.  If it is, then  what is the issue of not considering it at 70deg,  just as one would if using t&e for instance instead  as some/many do  ?

"...However, with heating appliances I think it's worth remembering that heat can be conducted away from the appliance through the copper ... 

And also consider whether, under/behind the hob (or over) is the ambient temperature really limited to the 30 deg C as assumed by Tables 4F1A, 4F1B, 4F3A and 4F3B?"

Fair do's.  Should the underside of a hob in a counter top, or the lower rear of a built-in oven  ever get hot to be of concern....  

I'm still a bit  confused as to whether there is compliant scope to re-rate the cable CCC to 70deg ... or whether 60 is it in the example scenario presented  :-)