Approved Document P & Approved Document M in residential electrical installations
Two of the most important regulations to follow when it comes to electrical installations in domestic properties and dwellings are Approved Document P, and Approved Document M.
These regulations are focused on safety and accessibility, ensuring that anyone working on or operating these fixtures does so safely and easily. As with all electrical installations, they must be compliant with BS 7671.
Approved Document P
This document is the broader of the two, focusing on the safety of electrical fixtures at every stage of the process, including design, installation, maintenance and testing, as well as everyday use.
Note: If a building is redesigned to accommodate a change of use, or is expanded to include new dwellings, systems may have to be changed to reflect this. However, if the cables in the current building are still functional and up to standard, they can remain unchanged, even if it is an old system using old colour codes.
Design & installation
The design and installation section of the document states that: “Reasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining and altering the installations from fire or injury.”
These regulations specifically apply to installations that are designed to operate at either extra low or low voltage capacities, with extra requirements including:
1. Attached or in a residential dwelling
2. Power supplies in public areas of residential buildings that are used to power one or more dwellings, with the exception being power supplies to lifts
3. If a buildings power source is located inside of a dwelling, in a garden of a dwelling, in or on land associated with a dwelling, or shared with a dwelling
Adhering to these regulations must result in the following conditions being met:
1. Adequate protection against mechanical and thermal damage
2. The installations do not present any fire or shock hazards
Operation, maintenance & testing - Providing adequate information
Post installation, installers must provide sufficient information to ensure that the operation, maintenance and testing of electrical systems can be carried out safely.
Information that must be provided, aside from the current requirements outlined in BS 7671, include:
1. Installation certificates and reports, operating instructions, and logbooks, to ensure that property owners and occupants are aware of the work carried out at any time
2. Earth connections, bonds and items of electrical equipment such as consumer units must be fitted with permanent labels
3. For larger and/or more complex systems, detailed plans will need to be included
Maintenance, certification & testing
When it comes to certification under Approved Document P, there are three ways this can be done:
1. Self-certification – this can be done by anyone that is competent and registered and involved with the particular building or dwelling
2. Certification conducted by a building control body – someone approved by a private sector or local authority
3. Certification by a competent and registered third party
These types of officials can also carry out testing and maintenance work, as long as this work is done in accordance with BS 7671.
Which buildings are applicable under Approved Document P?
The scope of Approved Document P applies to the following types of buildings:
1. Outside of dwellings and appliances fitted to outside walls – such as lighting and air conditioning units
2. Outbuildings in dwellings
3. Common access areas of multiple occupancy buildings – such as staircases and corridors
4. Shared amenities of multiple occupancy buildings – including laundry areas and communal kitchens
5. Commercial/retail buildings that share any part of an electrical system with a residential property – such as flats situated above shops
However, there are circumstances in which Approved Document P does not apply, such as:
1. Commercial premises and domestic dwellings that share the same building, but not the same electrical system
2. As previously mentioned, Approved Document P does not apply to the power supply that operates the lifts in buildings such as blocks of flats
Approved Document M
Approved Document M focuses on the accessibility of various electrical fixtures, including sockets, switches and consumer units. These regulations are based on strict measurements for the placements of these sorts of fixtures, making them easy to reach and operate, even for those with accessibility issues.
When it comes to the specifics, Approved Document M outlines that sockets and switches used for outlets such as lighting should be between 450mm and 1200mm above the level of a finished floor. However, for practicality purposes, light switches should be installed at the upper end of this range, between 900mm and 1200mm.
You must also take corners in to account, for wheelchair users in particular, electrical outlets should be installed at least 350mm away from corners.
Different requirements apply for what are known for uninhabited areas, such as garages, outbuildings and kitchens. You should aim to have at a 100mm gap below the installation of the socket, to make sure the integrity of any cabling stays intact.
Electrical work often involves adhering to numerous regulations to ensure that every installation is not only adequately protected from faults and hazards, but to make sure that every user can operate their systems easily.
