Grouping factors domestic

[Buzz1980]

Hi all

question regarding grouping factors in a domestic house. is there still a need to apply grouping factor Calcs in a 3 bed domestic house hold, I mean do we apply grouping factors for going through joist holes,where there is say 9 cables going through a 32mm hole but length of grouping at a length of 100mm. Is the calcs required or is it just judgement where cables through a hole and still plenty of moving is acceptable ? Thanks in advance

 

[cliffed]

Amount sounds about right in 32mm hole,it’s pretty conventional circiuts were talking about here.
No different to conduit cabling say in 20 mm .
There will always be another hole drilled if required,so grouping can be done in a efficient way.

 

[Strima]

In an average domestic installation the conductors will rarely, if ever, reach any sort of meaningful operating temperature. As such I would not feel the need to apply rating factors for cables in this instance.

Caveat: I would assess this on each installation and intended use. If someone in the future decided to do lots of growing in the property then grouping would have to be reassessed.

 

[davesparks]

Assess the grouping in the normal way.
Normally every circuit in a domestic installation will fall under the less than 30% of FLC rule.

 

[Buzz1980]

Hi lads

thanks for the replies,yeah that is what I would think that domestic cables are not all fully loaded prob never will get up to full load so grouping factor in this situation won’t need to be applied.More for commercial and industrial situations ? Cheers

 

[davesparks]

Hi lads

thanks for the replies,yeah that is what I would think that domestic cables are not all fully loaded prob never will get up to full load so grouping factor in this situation won’t need to be applied.More for commercial and industrial situations ? Cheers

No, the assessment of grouping is for all situations.
It's not a case of 'probably never get up to full load' or not assessing the grouping of cables.
It is just that the assessed use of the cables will be under the 30% stated in the regulations.

 

[Buzz1980]

Ok ?. also some of the cables are going through engineering joists, where it’s about about a 10mm board. Will the grouping factors through these holes really matter in this installation purpose as the distance is so small plus i have counted nine circuits through a 32mm hole ?

 

[sinewove]

No, the assessment of grouping is for all situations.
It's not a case of 'probably never get up to full load' or not assessing the grouping of cables.
It is just that the assessed use of the cables will be under the 30% stated in the regulations.

That's 30% of the grouped rating Of each cable,not the the flc of said cable.
Regards,S