Hi all

Looking at the calculations for cooker cable ratings last night and decided
that I needed guidance on the selection of grouping factors.
Considering cables which run as a loose "loom" between the floors of a 2
storey house, would these be considered as closely grouped?
At points where they pass through joists they are touching, between joists,
some are touching and some have a cable or two diameters between.
If you believe that these do represent grouped cables, then surely almost
all installations are grouped (at least at the point where the cables bunch
to connect to the CU).
Also I can reasonably argue that the downstairs power ciruit alongside the
cooker cable is lightly loaded (or will be as I intend to break out the
kitchen onto a separate ring). So according to the On-Site-Guide I can
ignore this in the grouping equation. But what if a future occupant decides
to run electric heaters in each room?

I currently have a 6mm cable feeding a double oven and large hob. I don't
want to go to the hassle and expense of uprating this unnecessarily.
Taking diversity etc into account, it appears that a 51A rated load equates
to approx 22A for cable load sizing.

Any light that anyone can shed on this would be appreciated

TIA

Phil