The correct selection of cable size will depend on what your total load adds up to, the length of run between the house and summer house and the installation method. All of these factors play a part in determining the correct cable size. If the cable were installed buried in the ground, then it could carry up to a maximum of 36A without exceeding 70°C (as will be the temperature limit for a domestic installation typically). However, you also need to consider the circuit length and the associated voltage drop for the cable concerned. We would generally advise on a maximum voltage drop of 2.5%, which would limit your cable run to about 13m. If the cable were only carrying 25A, then the cable circuit length could increase to approximately 19m.
Answered by: Nikki - Prysmian
Date published: 2022-06-06