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I am trying to install a light onto a balcony and would like to do so according to the UK electrical code. I have a power socket on the other side of the wall, so I would like take power from that, run it through the wall to the other side and finally to the light. The entire apartment is behind an RCD in the consumer unit.

Questions:

  • Am I allowed to do this at all (in my own property), or do I need an electrician? Do I need to notify anyone that I am doing this work?
  • The power socket is fused for 16A at the electrical panel. The single light will not need more than 1A so I need a way to put a fuse in it, I'm assuming I can use one of those "fuse & switch" boxes on the indoor side, is this right and is there a better way?
  • What type of cable should I use on both sides (indoor side and outdoor side - note that outdoor would be exposed to the sun)? Do I need a conduit on the outdoor side or can I attach the cable directly to the wall?
  • Do I need a light switch on the outside? I plan on using a smart bulb so I don't need the functionality of a switch, but I wonder if it's required by code - if not the light fixture will always be live unless the indoors fuse is removed.
  • What kind of IP rating should I look for in the light fixture where the top is covered (by the balcony above) however there is risk of water going onto it from the side if the wind blows the rain sideways?

1 Answer 1

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  1. The Building Regulations (which determine whether work is notifiable or not) vary according to England, Wales, Scotland or Northern Ireland. Notifiable work must be notified to the local authority, either by a Building Regulations application or an electrician who is a member of a scheme which allows members to self-certify and register their work. Anyone can carry out electrical work; it is only a requirement to notify the work that may apply.

The latest version of Part P for England and Wales was introduced on 6 April 2013, the range of works requiring notification has been reduced.

Notifiable works are:

  • The installation of a new circuit
  • The replacement of a consumer unit
  • Any addition or alteration to an existing circuit in a special location (bathroom, swimming pool or sauna)

All other work is considered non-notifiable, namely additions and alterations to existing installations outside special locations, maintenance, replacement and repair work.

Part P England and Wales - Frequently Asked Questions

See also Approved Document P: Electrical safety - Dwellings (2013 edition) (PDF 2.33 Mb)

Other Building Regulations also apply, including Energy Efficiency - you may not be able to install a high-power halogen light.

  1. You should use a fused connection unit adjacent to the power socket. It is your choice whether to include a switch or not, but it would probably be advisable.

  2. You should use an appropriate cable for external use, such as NYY-J or "Hituff" cable. This can be run on the outside on the wall without conduit, provided it is not going to be subject to physical damage (so if it is running near ground level it may require a protective conduit or cover). It is available per metre from some electrical suppliers, including TLC

You may require a weatherproof junction box and glands on the outside to connect between the light fitting and the circuit wiring.

Note that the latest Amendment to the Wiring Regulations now requires all wiring to have sufficient metallic fixings that the wiring remains sufficiently supported in the event of a fire. This does not mean that every fixing must be metallic, and short lengths of wiring may not need any.

  1. You do not require a switch on the outside.

  2. The Ip rating depends on whether the light may be exposed to any form of jet washing.

The minimum IP rating you should look for in a garden light is IPX3 (normally IP43), which protects against rain or spraying water at a 60° angle from vertical. Choose an IPX4 (normally IP44) rating for exposed areas.

IP Ratings – A brief guide to Waterproof Lighting

This answer is not a complete guide to how to install an outside light. Good workmanship is required.

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  • Thanks for your answer - just ordered all the supplies. One question though, which cable should be within the wall? The hole isn't big enough for the NYY-J cable to fit so my idea is to put a weatherproof junction box to cover the outdoors side of the hole and get the indoors cable through the hole all the way into the junction box - would this be acceptable, or is it mandatory for the outdoor-rated cable to go all the way indoors? Aug 1, 2020 at 1:08
  • Also, I am using 1.5mm cable since it's a very short run and I will use nowhere near its max current capability as well as a "fused spur" box indoors with a 1A fuse so it's safe. My concern is that because the breaker in the consumer unit for this circuit is actually 20A, it means that if an idiot were to put the incorrect fuse in the fused spur then suddenly the overcurrent protection on the entire circuit is higher than the capacity of my cable. Is this a problem with regards to code and should I order thicker cable instead to make this "idiot proof" even in case of a wrong fuse being used? Aug 1, 2020 at 11:28
  • You can use an outdoor junction box if you want, but I would enlarge the hole to take the NYY-J cable. Best practice is to sleeve the cable in a short length of plastic conduit, whatever type of cable you use, to protect it from abrasion. You can use 1.5mm on a 3A fuse spur as anyone changing the fuse (or the light) takes responsibility for doing that. Depending on mounting method 1.5mm cable is okay for a 13A fuse anyway.
    – Owain
    Aug 1, 2020 at 14:23

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