Store/Help Guides/Sockets & Switches Guide
Wiring accessories look simple until you are standing in front of a wall of them. This guide walks through each product type in the BG Nexus range, what the numbers on the box mean and the details that stop a job going wrong: back box depth, earthing metal plates and LED dimmer loads.
1. Light switches: gangs and ways
Gang is the number of rockers on the plate. A 1 gang switch controls one light, a 2 gang controls two and a 3 gang three, all from one back box. Way is the number of switch positions controlling the same light. A 1 way switch works on its own. A 2 way switch is used in pairs, for a hall light switched from both the front door and the landing. Because a 2 way switch can be wired 1 way, nearly all modern switches are 2 way and that is what we stock.
All BG Nexus plate switches are rated 20 A 16AX. The AX rating matters for LED and fluorescent lighting, which draws a high current for a split second at switch on. A 16AX switch handles that without derating.
When a light needs switching from three or more places, for example a long landing with a bedroom at each end, the middle switches are intermediate switches. The two end switches stay 2 way and the intermediate sits between them. You can add as many intermediates as you need.
3. 13 A sockets: single or double pole
A 1 gang socket has one outlet and a 2 gang has two. The switch on a single pole socket breaks the live only. A double pole socket such as the 2 Gang 13A DP Switched Socket breaks live and neutral, so a switched off appliance is fully isolated. Use double pole in kitchens, utility rooms and for outdoor supplies. The Nexus Metal and Flatplate ranges are double pole throughout.
BG sockets have twin earth terminals for high integrity earthing, which is required where lots of IT equipment runs off a ring circuit, and outboard rockers so plugs never foul the switches.
4. Sockets with USB charging
USB sockets replace the wall adaptor. The 2 Gang 13A Switched Socket with 2 x USB-A 3.1A has two USB-A ports sharing 3.1 A, enough for two phones. The 2 Gang 13A Switched Socket with USB-A and USB-C 22W adds a USB-C port with 22 W power delivery, which fast charges a modern phone or keeps a tablet topped up. Choose USB-C where you can, as new devices ship with USB-C cables. Every USB socket needs a 35 mm back box because the charger sits behind the plate.
5. Fused spurs
A fused connection unit, usually called a fused spur, feeds one fixed appliance from a ring or radial circuit through its own fuse. Boilers, extractor fans, towel rails, cooker hoods and under cabinet lighting are wired this way. Pick the neon version when you want to see that a hidden appliance is powered, and the flex outlet version when the appliance cable comes out the front of the plate. Fit a 3 A fuse for lighting and fans, 5 A for most boilers and 13 A for heaters.
6. 20 A and 45 A switches
A 20 A double pole switch isolates an immersion heater, water heater or a fixed appliance up to 20 A. The neon and flex outlet version is the usual choice for immersion heaters and towel rails. Cookers and hobs need a 45 A cooker switch on 6 mm² or 10 mm² cable, or a cooker control unit that adds a 13 A socket for the kettle. Site the cooker switch within 2 m of the appliance but not directly above the hob.
7. Dimmers and LED lighting
BG Nexus dimmers such as the 1 Gang 2 Way 400W LED Dimmer are intelligent trailing edge dimmers designed for dimmable LED lamps, with a range of 5 to 100 W for LED and up to 400 W for halogen. Push to switch on and off, turn to dim. They work in 2 way circuits with an ordinary 2 way switch at the other end. Two checks before you buy: the lamps must say dimmable, and keep one lamp type per dimmer to avoid flicker.
8. Finishes and matching a property
- White Moulded: the BG 800 series. Slim 6.9 mm plates, rounded edges, the best value for rentals and whole house refurbishments.
- Nexus Metal Brushed Steel: raised plates with grey inserts, screw caps and brushed rockers. Hides fingerprints, suits kitchens and living rooms.
- Screwless Flatplate: a 3 mm brushed steel plate that clips over a hidden frame. The designer choice for new kitchens and extensions.
Every product type is stocked in all three finishes so a property can match room by room. Metal plates must be earthed, so older lighting circuits without an earth conductor should keep plastic switches.
9. Back boxes and depths
| Accessory | Minimum box depth | Notes |
|---|
| Light switches, blank plates | 16 mm | 25 mm is easier to wire; Flatplate switches need 25 mm |
| 13 A sockets | 25 mm | 35 mm recommended for double pole sockets on 4 mm² cable |
| USB sockets | 35 mm | Charger sits behind the plate |
| Fused spurs, 20 A switches | 25 mm | 35 mm if a flex outlet is used |
| Cooker switches and control units | 35 mm | 47 mm for 10 mm² cable |
| Dimmers | 25 mm | 35 mm keeps the dimmer cooler |
Use galvanised metal boxes in brick and block walls and dry lining boxes in plasterboard. A 2 gang accessory needs a 2 gang box; converters that turn a single box into a double are available but we recommend replacing the box.
10. Rules, heights and safety
- Switch off at the consumer unit and prove the circuit dead with a tester before touching any accessory.
- New sockets in homes must be RCD protected under BS 7671 regulation 411.3.3.
- No sockets within 3 m of the edge of a bath or shower, and only shaver sockets to BS EN 61558-2-5 in bathrooms.
- Part M height guidance for new builds: sockets 450 mm to 1200 mm from the floor, switches 900 mm to 1200 mm.
- Notifiable work, including new circuits and additions in kitchens and bathrooms, must be certified by a registered electrician.
If anything you find behind the old plate looks scorched, has rubber or fabric insulation, or there is no earth wire at a metal plate, stop and call us on 07307 565444. Those are signs the circuit needs testing before new accessories go on.
11. Frequently asked questions
What does 2 gang 2 way mean on a light switch?
Gang is the number of switches on one plate, so a 2 gang switch has two rockers. Way is how many positions can control the same light: a 1 way switch works alone, a 2 way switch is used in a pair so a landing light can be switched from upstairs and downstairs. A 2 way switch can always be used in a 1 way circuit, which is why most of our switches are 2 way.
Should I choose a single pole or double pole socket?
A double pole socket switches both live and neutral, so an appliance is fully isolated when switched off. It costs a little more and is the better choice for kitchens, outdoor circuits and anything you want to isolate for safety. Single pole sockets are fine for general use. All BG Nexus Metal and Flatplate sockets are double pole.
What back box depth do I need?
Light switches fit a 16 mm box, though 25 mm gives more room for cables. Standard 13 A sockets need 25 mm. Sockets with USB charging need 35 mm because the charger sits behind the plate. Cooker control units and dimmers are more comfortable in 35 mm or 47 mm boxes. If you are replacing an existing accessory, measure the box you have before ordering.
Will an LED dimmer work with my lights?
Only if the lamps or LED downlights are marked dimmable. BG intelligent dimmers are trailing edge and rated 5 to 100 W for LED loads, which covers up to about ten 8 W downlights, or up to 400 W of halogen. Mixing lamp brands on one dimmer can cause flicker, so keep each circuit to one lamp type.
What is a fused spur for?
A fused connection unit takes a supply from a ring or radial circuit and protects one fixed appliance with a 3 A, 5 A or 13 A cartridge fuse. Boilers, extractor fans, heated towel rails, under cupboard lights and waste disposal units are all wired through a fused spur rather than a plug, and the switched version lets you isolate the appliance for servicing.
Can I change sockets and switches myself?
Replacing an accessory like for like on an existing circuit is not notifiable under Part P in England and Wales, so a competent DIYer can do it with the power isolated and tested dead. Adding new sockets in kitchens or bathrooms, new circuits or anything outdoors is notifiable and should be done by a registered electrician. We fit everything we sell across London.
Do brushed steel and flatplate ranges need an earth?
Yes. Metal plates must be earthed through the earth terminal on the accessory, which means the circuit needs an earth conductor at that point. Most homes wired after the 1960s have one. Our electricians check this as part of any installation, and older lighting circuits without an earth should stay on plastic switches.
