Well, I would have been less initially confused if the context had not suddenly jumped
Bernard suggested that some domestic ovens had bifilar elements, and I replied saying that I hadn't come across that, and then that didn't really understand why they would adopt such a design (for such a product). Simon then quoted that comment from me and replied, talking about "doing maintenance from just one side of the ducting" - which left me initially somewhat scratching my head as regards what sort of ducting one might find in a domestic oven.
Kind Regards, John