It’s important that the electrical system in your garden office complies with Part P of the Building Regulations, to achieve this; the electrics need to be installed by a certified electrician. Compliance with Part P means the electrics have been installed to a high standard and most importantly they are safe. Many garden offices have the electrics installed in the wall panels whilst in the workshop – it’s important to confirm with your supplier that the electrics have been certified to comply with Part P; after all you can’t see what’s behind the walls! A certified electrician is needed again once the building is installed on site to connect the electrics to the mains supply and test the system.
One of the few additional costs when buying a garden office is the connection of the electrical system to the mains supply. This involves running an armoured cable from the consumer unit in the garden office to the main house supply. This armoured cable needs to be buried in the garden, a trench is dug approximately 500mm – 750mm deep, the armoured cable is laid in the bottom with a warning tape laid above, and the trench is backfilled with earth and the garden made good. The electrical cables need to be buried like this so that if the ground is disturbed in the future, such as when you are digging, the cable is deeper than the average spade depth and people will come across the warning tape first alarming them that there is an electrical cable below.
This connection needs to be made by a certified electrician; the cost can vary depending on your site, how far the garden office is from the house etc, but as a rough guide allow between £500 and £1,200 for this connection. Once your electrician has made the connection, they will test the circuit and issue a certificate.
Garden office electrical systems normally comprise of a consumer unit (fuse box), power sockets, light switches and lights, some companies include outside lighting, heating, telecommunications and audio visual systems, burglar and smoke alarms. When reading the garden office specifications assume that fixtures and fittings are white unless stated otherwise.
It’s not always clear from the specification list if a garden offices electric cables are hidden within the wall structure or mounted on the surface. Electrics installed within the wall structure have light and power sockets mounted flush with the wall, and the finished effect is like you would find in any modern home. Surface mounted electrics are just that mounted on the surface of the wall, the cables are hidden in conduit which is fixed to the wall, the light and power sockets stand proud from the wall, this is a more industrial look and not aesthetically pleasing to some people, but is cheaper to install. Another type of surface mounted electrics is the dado system, this system is often focused on one wall, all the cables are hidden in a wide trucking, which has a number of power sockets, light switches and telecommunication points fitted in it, you’ll have seen this type of system in offices, schools and hospitals. With this type of system it is relatively easy to add extra sockets at a later date as the cables are easily assessable in the channel, the downside is that it’s not always ideal having all the electrics fitted in one area of the garden office, you could end up with trailing cables.
It’s worth thinking about where you will position furniture in your garden office early on for instance if you have space for a sofa you may want to place a side light beside it so it would make sense to have a power socket nearby so as not to have trailing cables. Another example would be if you are having a wall mounted TV you may want a power socket behind the screen so there are no visible cables. The market is divided into companies who have their power sockets in set locations e.g. the four corners of the office whilst others have total flexibility in socket location, find out which camp your supplier fits in early on in the project.
Always specify a couple more sockets than you think you will need – we all keep accumulating electrical goods and you will be pleased you have enough sockets to power them.
There’s obviously more to garden office electrical systems than power sockets and we will look at lighting, heating and communications in future chapters of this guide.