Electrical – Induction cooktop connection

In this case, you would simply not hook up the neutral wire. Instead you can just put a wirenut on it and tuck it neatly into the electrical box.

Typically 240V appliances require the neutral wire so that they can run the electronics at 120v or provide a plug on the appliance. In this case, these devices are hooked up to one leg of the hot and the neutral, giving 120V.

If no neutral is required, then the device can only operate on 240V/208V, though at 208V you should expect the oven to take longer to heat up.

What it means by "Connect only to a 3-wire, 120/240-volt power supply; the neutral conductor is not required for the operation of the appliance," is that the 240V needs to come from two legs of 120V service; this device won't function on 240V mains like you'd find in Europe.

Those cables have totally different applications. On the left, you have common household power cable in the modern EU (IEC) colors:

• Ground: mandatory green/yellow
• Neutral: mandatory blue (today; older installations use other colors)
• Hot: by common practice, brown

The American equivalent is bare-white-black. These colors in 14-2 Romex (jacketed cable; 14 gauge; 2 conductors +ground) is used all over the place in every US home.

The right is for three-phase power, specifically "delta" power (which by definition does not have a neutral.) That is why there is no blue "neutral" in the bundle. This is bigger power, for heavier loads such as factory lighting or air conditioning in a large retail store.

It'd be an odd duck in residences — while three-phase "wye" power comes down your street (230 V to neutral, 400 V phase to phase), it's rare to pull all 3 phases into a home. Probably more common in a townhouse (mansion) or a 12-unit apartment block. Because of its notable lack of neutral, this cable would only be useful for running large motors or heating units, say to deliver 400 V delta to a large air conditioning unit of 5 kW capacity. Here are the IEC color codes:

• Ground: mandatory green/yellow
• Phase 1: Brown
• Phase 2: Black
• Phase 3: Gray

Black is no longer legal for neutrals in the UK, and unless the cable is pre-2004 old stock, it is certainly intended for 3-phase delta, since the colors are just right for it.

What I hear from Euro folks is this is how normal 3-and-earth is sold, and you are expected to re-mark one of the phase wires to be neutral (if you need neutral). I would re-mark the black, since you should take it "out of play" as it's not a valid neutral color anymore, so that'll reduce confusion.

Note: North American people can never re-mark or re-sleeve wires, *except in cables, they can re-mark a white (neutral) wire to be a phase/hot. In wiring where only certain wires are always-hot, the remarked white must be used for the always-hot.