Neff built-in cooker question

[baker210]

I have a Neff B1442 built in electric oven which has been installed in an ordinary domestic supply. For some reason, the heatproof flex which came with it is 4 core, i.e. 3 black and 1earth, instead of the usual 3 core brown black and earth. On the back of the cooker, a plate shows 4 different wiring options, with the last one being for 220-240 volts. This shows a straightforward live neutral and earth connection which is what I want to use. The others are 2 400volt options and 1 220-230 volt option, all of which employ 4 core connection. As i know the oven has been connected to a standard domestic mains single phase supply, I cannot understand why a 4core flex has been used. Can anyone enlighten me? The oven has been used with a matching Neff halogen hob which I am not using. Should I just remove the 4 core and substitute compatible 3 core? Has the 4 core been used in conjunction with the hob?

[AlBags]

Have you looked at a manual?

[baker210]

I should have investigated further before posting this question! For some reason the previous installer had employed 4 core flex and snipped one of the cores off so it could be used as 3 core. The internal cooker connection plate had the usual LNE connections so it was simply a matter of tracing which cores were which with a circuit tester, at the cooker unit supply end, and marking the live with red tape. I wanted to use the attached flex as it was heavy duty & heatproof.
Error: 3 core flex is of course brown blue and earth, not brown black and earth as referred to in my question.