Installing an electric cooker

Summary: Learn how to wire and install a free-standing electric cooker, connect to the control unit, connect to the connection unit, connect to a free-standing cooker, connect to the consumer unit and fit a separate hob and oven.

* Notifiable project requiring Building Control approval. Installation must conform to Electrical Regulations.

An electric cooker must be connected to a separate circuit run from the consumer unit to avoid overloading the main circuit. The supply cable is connected to a double-pole isolating switch which is the cooker control unit situated on a kitchen wall. It must be above work top height and positioned to the side of the cooker, never above it. The cooker control unit may have a small neon light, which is illuminated when the control unit is switched on.

A cable then runs from the control unit to a cooker connection unit fitted 600mm (2ft) above floor level on the wall behind the cooker. The cooker is connected to the connection unit by a 2m (6ft 6in) length of cable. This allows the cooker to be pulled away from the wall when required.

If you have a separate oven and hob, these can be connected to a single control unit providing that they are less than 2m (6ft 6in) from the control unit. The Installation process may vary for different models of cooker, so it is essential to read the manufacturer's instructions carefully.

Installing a free-standing electric cooker

Plan the cable route from the cooker control unit to the consumer unit. The size of the two-core-and-earth cable you will need will depend on two factors: the length of cable required and the wattage of the cooker you are installing.

The 2m (6ft 6in) length of cable running from the connection unit to the appliance will be the same size as the cable used for the rest of the circuit. The cable can run under floorboards and in chases in the plaster. If you decide to use this method remember the cable must be covered by PVC conduit to offer some protection against nails and screws that may be driven into the wall at a later date. Alternatively, the cable can be surface-mounted in plastic trunking and run at floor or worktop level.

Measure the distance between the consumer unit and the control unit, and from the control unit to the cooker to find the length of cable you will need.
Lay the cable along the prepared route.
Fit mounting boxes for the cooker's control unit and its connection unit.

Cooker Wattage	Fuse or MCB	Distance (m)	Cable
Up to 12kW	30 amp	Up to 20m	6mm²
Up to 12kW	30 amp	Between 20-30m	10mm²
Above 12kW	45 or 50 amp	Up tp 10m	10mm²
Above 12kW	45 or 50 amp	Between 11-22m	16mm²

Connecting to the control unit

Strip the outer sheath from the end of the cable. Then cut each core so they are the correct length to reach the terminals.
Strip the insulation from the ends of the Brown/Live core and the Blue/Neutral core. Cover the Earth core with Green-and-Yellow insulation leaving approximately 15mm of core exposed. Twist the strands of each core.
With the mounting box fixed in its position above worktop height and to the side of the cooker, connect the cable running from the consumer unit to the terminals marked "IN" of the cooker's control unit. Brown to the Live terminal, Blue to the Neutral terminal and Green-and-Yellow to the Earth terminal.
The cores of the cable running from the connection unit to the control unit should be prepared as above. The cores should then be connected to the control unit terminals marked "OUT". Brown to the Live terminal,
Blue to the Neutral terminal and Green-and-Yellow to the Earth terminal.
Screw the face-plate of the control unit to the mounting box.

Connecting to the connection unit

With the mounting box of the connection unit fitted 600mm (24in) above floor-level behind the cooker, it is time to connect the cores from the cables running from the control unit and from the oven to the terminals in the connection unit.
Strip the outer sheath from the ends of the cables. Then cut the cores of each cable so they are the correct length to reach the terminals.
Strip the insulation from the ends of the cores of both cables and cover the Earth cores with Green-and-Yellow insulation leaving approximately 15mm of core exposed. Twist the strands of each core.
Unscrew the face-plate from the metal frame on which the terminals are located. Then unscrew the cable clamp on the frame and feed the cable from the cooker under it.
Match the cores from the cable running from the control unit with the cores from the cable running from the cooker. Connect both Brown/Live cores to the single terminal L. Similarly connect both Blue/Neutral cores to the single terminal N; and both Green-and-Yellow/Earth cores to the single terminal E.
Tighten the cable clamp on the frame and screw the frame on to the mounting box.
Screw the face-plate back onto the connection unit.

Connecting to a free-standing cooker

Strip the outer sheath from the ends of the cable running from the connection unit to the cooker.
On the back of the cooker there will be a metal plate which when removed will reveal the cooker terminals.
Loosen the cable clamp and feed enough cable under it to reach the terminals. Then cut the cores so they are the correct length to reach the terminals.
Strip the insulation from the ends of the Brown/Live core and the Blue/Neutral core; and cover the Earth core with Green-and-Yellow insulation leaving approximately 15mm of core exposed. Twist the strands of each core. Connect the cores to the appropriate terminals: Brown/Live to terminal L, Blue/Neutral to terminal N and Green-and-Yellow-Earth to terminal E.
Tighten the cable clamp and replace the metal plate on the back of the cooker.

Connecting to the consumer unit

The supply cable is now connected at the cooker, the connection unit and the control unit. All that remains is to connect the supply cable to the consumer unit. To do this you will need a spare fuseway or MCB. If there is none spare, you will need to consult a professional electrician.

Strip the outer sheath from the end of the cable.
Cut off the power supply at the consumer unit.
Switch off the MCB or remove the fuse carrier to the circuit that will supply the cooker you are installing.
Although it is not connected, check that the control unit and the cooker are both switched off.
Unscrew and remove the cover of the consumer unit.
If you have a wooden consumer unit you will need to drill a hole in the frame to feed the cable through. If your consumer unit is plastic or metal, press out an entry hole for the cable.
Insert a grommet into the hole and feed the cable through.
Cut each core so they are the correct length to reach the terminals.
Strip the insulation from the ends of the Brown/Live core and the Blue/Neutral core. Cover the Earth core with Green-and-Yellow insulation leaving approximately 15mm of core exposed. Twist the strands of each core.
Connect the Blue/Neutral core to a spare terminal on the Neutral terminal block. Then connect Brown/Live core to the terminal on the spare fuseway or MCB. Finally, connect the Green-and-Yellow/Earth core to a spare terminal on the Earth terminal block.
Switch on the MCB or replace the fuse for the new circuit.
Replace the cover of the consumer unit and switch on the mains supply.

Connecting to a separate hob and oven

A separate oven and hob can be fed from a single control unit, but neither the oven nor the hob should be more than 2m (6ft 6in) from the control unit.

You can either run a single cable from the control unit to first the oven then on to the hob (or the other way round). Alternatively, run two cables from the control unit: one to the oven, the other to the hob. You do not have to fit connection units to the wall behind the oven or the hob.

If you have run a single cable from the control unit to the first component (oven or hob), two cables need to be connected to the appropriate terminals - the cable from the control unit and the cable from the first component (oven or hob) to the second.

Match the cores from the cable running from the control unit with the cores that run from the first component to the second.

Connect both Brown/Live cores to the single terminal L.

Connect both Blue/Neutral cores to the single terminal N.

Connect both Green-and-Yellow/Earth cores to the single terminal E.

The cable running from the first component (oven or hob) is then connected to the second component.

Alternatively, if you have connected two cables at the control unit, connect the other end of one cable to the hob and connect the other cable to the oven, following the method for connecting up a free-standing cooker (above).