Only top entries are rolled, though. There are other, various knockouts too.As #3, most have rolled edges. No need for grommit. And if you do use a grommit, the hole becomes too small to fit many cables in.
Fnar fnarBit snug, but squeezed in in the end.
Perhaps, but the area of the hole will be smaller, ergo the available space for cables is smaller.Is this a wind up ? the circumference is the same oval or round.
Reply to the thread, titled "Oval Grommets for 15mm boxes" which is posted in UK Electrical Forum on Electricians Forums.