Sound System Installation in NR14

Two different jobs share this name. Domestic multiroom audio is ceiling speakers wired back to one amplifier position, usually a cupboard or a loft rack. Commercial background music runs on 100 V line distribution, so a long run of speakers can share a single amplifier with very little volt drop.

The electrical work is common to both. Speaker cable is a Band I circuit and mains is Band II, and Regulation 528.1 of BS 7671 keeps them apart: no shared trunking compartment, no long parallel run alongside twin and earth, cross at right angles. Every ceiling speaker is also a hole in a ceiling. In a flat, an HMO or anything with a compartment floor, a fire hood behind the speaker restores the fire rating, and it cuts the sound carrying into the room above. First fix pulls the cable and the mains supply for the rack before the plasterboard goes on. Second fix cuts the apertures and terminates.

One thing worth saying plainly. A background music system is not a voice alarm system. Anything that broadcasts an evacuation message is life safety equipment under BS 5839-8, with fire-rated cable and a design built around speech intelligibility.

We install multiroom audio and 100 V line systems for pubs, shops and village halls, and we will happily do just the first fix if you have an AV company doing the kit. Getting the containment, the cable routes and the power in before the plaster goes on is the difference between a tidy job and trunking down a wall.