Note 1 of table 4C1 in Apdx 4, says that the factors are applicable to uniform groups of cables, equally loaded. However, I see some publications that apply these factors to ccts, in trunking, for example, with no reference to cables being equally loaded (as though it's a belt-and-braces approach and apply the factors regardless).
So what is your interpretation of equally loaded? It could apply to cables in conduit or trunking supplying heaters or conveyor belt motors, for example, all on for long durations. But what of cables supplying e.g. ring f. ccts, an EVC and other ccts, such as in domestic settings? Can they basically be ignored from such grouping factors or apply them regardless just to be in the safe side?
In domestic and similar situations, remember that the total long term load is limited by the cut out fuse. Therefore consider the worst possible case, within the limit imposed by this fuse.
This might be 3 ring final circuits fully loaded. So allowing for the loading being unbalanced between legs of these rings, that is three cables loaded to 12 amps each and another 3 cables loaded to 20 amps each.
And remember that with three fully loaded ring circuits, that ALL other cables in the installation can be ignored for grouping as they cant be carrying more than 4 amps in total.
For an electric vehicle charger circuit, which is liable to be a long hour load, I would be inclined to upsize the cable for energy saving. And also to route it away from all others.
In domestic and similar situations, remember that the total long term load is limited by the cut out fuse. Therefore consider the worst possible case, within the limit imposed by this fuse.
This might be 3 ring final circuits fully loaded. So allowing for the loading being unbalanced between legs of these rings, that is three cables loaded to 12 amps each and another 3 cables loaded to 20 amps each.
And remember that with three fully loaded ring circuits, that ALL other cables in the installation can be ignored for grouping as they cant be carrying more than 4 amps in total.
For an electric vehicle charger circuit, which is liable to be a long hour load, I would be inclined to upsize the cable for energy saving. And also to route it away from all others.
