New cooker help + wiring

Sounds unusual, ours came with three-core flex which needed to be wired into the plate on the kitchen wall. Essentially it's the same as wiring a plug, except it's vital that there is an excellent connection with as little resistance as possible (which at the high currents involved could lead to heat being generated and ultimately a fire). That means making sure that the terminals are free from corrosion and that the copper is firmly gripped in the terminals (screws tight, but not so tight that the thread is put under too much stress which could cause it to fail). If you're not comfortable with it get an electrician in. Part P of the Building Regs may have something to say on whether you're allowed to do it yourself, but I've always ignored it completely.

You think an electrician will have the necessary nouse to tighten the terminals correctly? They're about as good as gasmen, looking for leaks with a naked flame.

Wiring a cooker to an existing cooker point is fairly straight forward. One ought to use a high temperature silicone insulated flex for connection, but most people use 4 or 6mm^2 T&E since its far easier to get hold of, and the cooker is unlikely to be moved that often anyway.

Check that the wiring from the CU to the cooker point is adequate. Ours was not adequate for a double oven.

Fair point, I tend to agree, which is why I'd rather do it myself and know that it's been done properly. But if you really don't know what you're doing, at least if you get an electrician in and the house burns down a month later your conscience is clear!

I found quite a few c*ck ups in my professionally-wired house when I moved in. The most baffling was the staircase lighting - four switches which had to be switched in a certain permutation before any light would appear. Whoever had done it clearly did not understand intermediate switches or how to wire them. To be fair neither did I but an hour or two on google (specifically searching this group) and I sorted it out! Presumably the guy realised it wasn't working properly when he did, but he couldn't be arsed to work out why not and just took the money and ran before anyone noticed.

I've just fitted a built in fan oven from Curries - the instructions stated H05VV-F 3 x1.5mm^2

John

A fan oven doesn't take that much on its own.

Couple of weeks ago I wired in a neighbour's new electric cooker: the book said 9kW and at least 4mm^2 cable. The MCB is 40A (so OK for 9kW) and I used 6mm^2 FTE.

For a standalone cooker you can use 6mm FTE (PVC or LSOH) or 6mm H07RNF flex. Electrical factors & marquee suppliers will do 6mm H07RNF flex.

Ironically for compliance with regulations you should use flex, but most cooker cord outlets wiring accessories and some cooker cable inlet hole & cord grip's appear to be designed for flat cable. So you might actually find yourself filing cooker metalwork if you do use round flex. Comes down to how often you pull out a cooker for cleaning, PVC FTE is not really the right cable but has been used for donkey's years. Similarly flex really requires bootlace ferrules for the cord-outlet plate end and often ring terminals for the cooker end, which is two ratchet crimp tools.