Can I run a 32-amp cooker circuit in a 2.5mm cable if the run is short – Advice from Electriman, North London Electricians

It is a very common question and an understandable one. If the cable run is only a metre or two, you might think the resistance is so low that a smaller cable would cope. Unfortunately, that is not how cable sizing works in UK wiring regulations, and using 2.5mm cable on a 32-amp cooker circuit would be unsafe and non-compliant.

Why cable size matters more than length

Cable is sized primarily by how much heat it can safely carry continuously, not just by its resistance. A 2.5mm twin and earth cable in the most favourable installation method, clipped directly to a surface with nothing around it, is rated at roughly 27 amps. The moment you push 32 amps through it, the conductor runs hotter than it is designed for. Over time, or under sustained load, that heat degrades the insulation, creates a fire risk, and can cause the cable to fail.

What about short runs?

A shorter run does reduce voltage drop, and BS 7671 does allow you to consider voltage drop as part of the design. However, voltage drop is a separate consideration from current-carrying capacity. A short run of 2.5mm cable still cannot safely carry 32 amps continuously. The two calculations are completely independent of each other.

What cable does a cooker circuit actually need?

For a standard 32-amp cooker circuit in a domestic property you need:

6mm twin and earth cable as a minimum for most installations.

A 32-amp Type B or Type C MCB or fuse at the consumer unit

Need a qualified electrician in North London?

Electriman covers Mill Hill, Barnet, Finchley, Edgware, Enfield, Watford and surrounding areas. All work is Part P certified and fully insured.