Derating factors

[RJP1]

hi i was doing a 17th edition practice exam and got a question about a cable running through a cavity with thermal insulation of 50mm, it asked for the derating factor for it.
i cannot find derating factors in the index of the regs book, could anyone point me in the right direction to find the derating factors eg- page numbers etc
thanks

 

[telectrix]

look in osg appendix 6. table 6B in red osg. page 125. not got yellow copy so may be different

 

[Paul.M]

BYB Appendix 4 table 4A2 is a good read. Take it from there

 

[Andy78]

It's under T for thermal insulation in the index of the BYB.

 

[telectrix]

typical IET. should be under I for insulation. if i was looking for long johns, then i'd look under T for thermal.

 

[Guest77]

typical IET. should be under I for insulation. if i was looking for long johns, then i'd look under T for thermal.

Tel if you would have kept your Regs book and not used it when you ran out of loo roll you would have known that

 

[Paul.M]

Cheers Andy

Reg 523.9 page 132 BYB. Done your home work for you.... Merry Xmas

ps, welcome to the forum.

 

[Andy78]

typical IET. should be under I for insulation. if i was looking for long johns, then i'd look under T for thermal.

It's also under I for insulation, thermal, cables in, and under C for cables in thermal insulation. Can't see how the OP missed it really.

 

[Paul.M]

erm,,, still in training?? May need a bit of guidance??

 

[telectrix]

simple really. 50-100mm of insulation, cable will cope. 100mm -400mm use nextr size cable. over 400mm use next size but 1 as long as it's double the csa. who needs regs?

 

[Andy78]

erm,,, still in training?? May need a bit of guidance??

Guidance for the OP
If you can't find the location of an answer to a 17th edition exam question using the index, use other relevant and related words contained within the question to reference the index with.

 

[Paul.M]

Guidance for the OP
If you can't find the location of an answer to a 17th edition exam question using the index, use other relevant and related words contained within the question to reference the index with.

^^^ good advice. Look at the key words within the question.

 

[RJP1]

thanks guys appreciate the reply's really helpful