4mm T&E in insulation

[Bluehair]

Table 4D5 gives all reference method 103 CCCs as exactly half of the reference method C CCCs apart from 4mm T&E.
Table 4A2 does not clear things up.

So anyone any ideas why 4mm T&E has a greater than 50% reduction in it's CCC when installed in insulation?

 

[EFLImpudence]

Misprint. 50% is the maximum derating factor.

 

[Bluehair]

So which bit is incorrect?

 

[EFLImpudence]

So which bit is incorrect?

The bit that doesn't give the value as exactly half

 

[Bluehair]

Are you saying the 37A Ref method C is correct and and the other reference methods are incorrect?

There is a glaring error (basically the 50% reduction in CCC) in the tables. I have never seen an erratum to correct the table.

Of course the regs have never has a misprint before have they?

 

[EFLImpudence]

Are you saying the 37A Ref method C is correct

Yes, that is correct - 37A is correct.

and and the other reference methods are incorrect?

Yes, 103 should be 18.5.

The maximum derating for a cable completely surrounded by thermal insulation for 500mm. or more is 50%.

Have you come across a situation where it would make a difference?

There is a glaring error (basically the 50% reduction in CCC) in the tables. I have never seen an erratum to correct the table.

Nor have I.

Of course the regs have never has a misprint before have they?

 

[Bluehair]

Thank you.

And the tables have been published for how long without anyone noticing this discrepancy?

 

[EFLImpudence]

4D5 has ONLY been around since 2008.

I hadn't noticed.