Cable size for 4920 amp cooker

The cooker control switch (i.e. the isolation switch), should be readily accessible such that the oven can be quickly and safely isolated in the event of an emergency or fault occurring on the cooker. Having the switch in an inaccessible place such as behind the oven is not-compliant with the BS7761:2008 wiring regulations. In theory a 4920 watt load will draw around 21amps, so a 2.5mm cable is just about adequate. As the temperature rating maybe exceeded, HOFR Trailing Flexible H05BN4-F 2.5mm flex should be used to connect the cooker rather than standard 2.5mm twin and earth cable. As a standard plug and socket has a maximum rating of 13amps the cooker/oven will need a separate circuit and a 20amp or 32amp double pole isolation switch. Standard 2.5mm twin and earth cable can be used up to the isolator, but the 1m connection to the oven itself should be the heat resistant flex. It would be best to use a 20amp BSEN60898 MCB as a 32amp one will not be compliant with BS7671 as it fails to protect the cable.

Yes 2.5mm is fine. To determine the correct cable to use a simple equation of ohm's law can be used. If you divide the watts by the voltage e.g 4920/230v = about 21amps, however you cannot get a 21amp breaker(mcb) so you would use a 32a so anything on a 32 amp mcb cannot be lower than a 2.5mm twin earth. Your cooker switch should not be within 500mm from the cooker space but you can have an outlet behind the cooker, being next to the gas point isn't really an issue. hope this has been helpful

Hi, 1) Really depends on the length of the 2.5mm cable, but if clipped direct for entire length then it is likely that the cable can take the load. Also, the correct over current device needs to be selected, a 32A MCB will not protect the cable and a 20A MCB may be too small for your oven. Typically a 6mm cable is taken to the cooker switch and the correct heat resistant flex(s) from that point. 2) Appendix 15 of BS 7671: 2008 gives advice on ring final circuits and sharing/spreading the load around the circuit. Item (iii) suggests that cookers, ovens and hobs over 2 kW should be on their own dedicated circuit. Whilst connection to a ring circuit is possible it would be very easy to overload the ring and this is therefore to be avoided. Sometimes the cooker switch has a 13A socket on it but this does not mean that it is part of the socket circuit. 3) The cooker switch needs to be "readily accessible". If it is behind the cooker then this does not comply. Can you advise if you had a Part P registered electrician to do the work? I would be very interested to know.....

Hi All. Why nobody told about max. demand and diversity? 4500 watts cooker will use about 13Amp. It is recommended install cooker switch within two meters of the appliance but not directly above it. Hope it helps VA Electrical.

Hello Dan, Title of your question regardingyour cooker installation differs quite a considerable amount fella lol. 4920amps differs from your then stated maximum wattage of 4500 so I’ll try to answer both here.... Basically a 2.5mm radial circuit has a maximum allowance of around 20amps so if you tried to wire something that demands nearly 5000 amps more than that on to that cable it basically wouldn’t even turn on before tripping, also as your main income room would only be a max of 100amps you’d soon find yourself in the dark pal haha! Basically, on a 2.5mm it has to be on its own circuit because it so close to the maximum load so if anything else on the circuit it’s gonna blow. Never put an oven on a plug top as because of its consistent pull it will melt the outlet before blowing the fuse. Also your oven is too powerful to be put on a plug top and should be hard wired. The isolation switch should actually be placed into the nearest convent position and the only actual reg states that you cannot place it or any other outlet within 100mm of the edge of the hob unit. Also there clearly is stated regs regarding electrical cables and the minimum distance required between them and any installation pipe work which is a minimum of 25mm. Hope this helps.