When two properties share a single electricity service cable it’s called a ‘looped service’. These are often found in terraced or semi-detached houses. In most cases, a single service supplies only one building.
You can see how it works in the diagram below: Electricity enters Premises 1 via the service cable which branches off from the mains, which usually run underneath the road or pavement outside. Then a looped-service cable runs from the meter in Premises 1 to the meter in Premises 2. The ‘service’ is terminated near the meter at a ‘service head’ or ‘cut-out’ which contains the main fuse.
If you have a looped service, you share a length of cable with your neighbour
What do you need to do?
Although a looped service is perfectly safe, it can lead to difficulties if you or your neighbours ask the electricity distributor (the "DNO") to provide more power. For example, one of the households might want to install an electric car charge point such as a zappi.
Your neighbours will likely need to be involved because the DNO will have to replace the looped service with a new service cable direct from the mains outside, (see diagram 2).
No EV charger should be fitted to a looped supply without prior authorisation from your local DNO
Although the zappi has intelligent dynamic load balancing which will fully protect your properties incoming main fuse, this cannot protect the main service cable which provides power to both you and your neighbours properties
The first thing to do if you aren't sure is to contact an installer who can offer advice and tell you whether the DNO needs to be consulted PRIOR to having the zappi installed or whether you can continue with the zappi installation and get the installer to notify the DNO afterwards.
Follow this link to find your Distribution Network Operator (DNO) should you need to seek advice from them.