A landlord asked an electrician to wire a normal double socket behind an HMO bathroom's new illuminated mirror, and was refused on the spot. A shaver socket isn't a smaller plug socket, it contains an isolating transformer that separates the circuit from mains earth, which is what actually makes it legal inside a bathroom's electrical zones. This guide covers why isolation is the real distinction, which zones permit a shaver socket versus none at all, and why a mirror's socket position still has to respect zone rules regardless of how integrated it looks.