Volume 4
Chapter 14 Electrical Installations
14.1. A house meets the tolerable standard if, in the case of a house having a supply of electricity, it complies with the relevant requirements in relation to the electrical installation for the purposes of that supply.
Introduction
14.2. The tolerable standard is amended by the Housing (Scotland) Act 2006 and now includes this new element covering electrical installations. For the first time assessors will look at the nature and condition of an electrical installation in a house when deciding if the house meets the tolerable standard. This element of the standard only applies to houses that have electrical installations connected, or capable of being connected, to a supply of electricity.
14.3. This chapter of guidance aims to provide the information and advice needed to carry out a thorough assessment of the electrical installations in a house for the purposes of the tolerable standard. The guidance takes account of the variety of experience and expertise assessors may have of electrical installations. The methodology is based on the normal walk-through survey used for other elements of the tolerable standard, with the potential for support from a qualified specialist.
Legislation
14.4. The tolerable standard was first defined in the Housing (Scotland) Act 1969. The Housing (Scotland) Act 2006 introduced this new element. The introduction of electrical installations in the tolerable standard is primarily in recognition of the danger unsafe wiring poses to the occupants of a house.
Definitions
14.5. The revised tolerable standard includes specific definitions for two of the terms used. These are:
14.6. Electrical installation: "the electrical installation" is the electrical wiring and associated components and fittings, but excludes equipment and appliances. This broadly covers all aspects of the supply, distribution and use of electrical power in the house from the consumer unit (where the electric supply connects to the wiring in the house) to the point of use at the switch or socket outlet.
14.7. Relevant requirements: "the relevant requirements" are that the electrical installation is adequate and safe to use.
14.8. Assessors may also find the following definition helpful:
Supply of electricity: this will normally be a public mains supply of electricity, but also includes supplies from any type of private generator. A house does not need electricity to meet the tolerable standard.
14.9. The next part of this chapter gives advice for assessors on how to judge if a house has an electrical installation that meets the tolerable standard.
The Wiring Regulations
14.10. The tolerable standard requires electrical installations to be adequate and safe. The national standard for electrical safety is BS 7671 (known as the Wiring Regulations) and is published by the Institution of Engineering and Technology ( IET). The Wiring Regulations are non-statutory, but they can be used to demonstrate compliance with a statutory obligation. For example, Scottish Building Standard Agency ( SBSA) Technical Handbook states that a new installation conforming to the standard set in the Wiring Regulations will satisfy the safety requirements for electrical installations in the Building (Scotland) Regulations 2004.
14.11. The Wiring Regulations recommend that existing electrical installations are inspected and tested regularly to ensure that they have not deteriorated and become unsafe. They recommend that a competent person inspects and tests the electrical installation against the regulations and completes a Periodic Inspection Report ( PIR). However, there is no statutory requirement for owner-occupiers in private houses to have their electrical installations periodically inspected and tested.
14.12. Some houses may have been inspected and tested, for example owners of Houses in Multiple Occupation ( HMO) are required to have the electrical installation inspected at least every 3 years, and in these cases the local authority may have a copy of the report on file.
14.13. There is no government-approved scheme for registering electricians competent to carry out a periodic inspection and local authorities should satisfy themselves that the electricians they intend to use are competent. The Electrical Contractors' Association of Scotland ( SELECT) and the National Inspection Council for Electrical Installation Contracting ( NICEIC) have, as members, electrical contracting companies they consider competent. The Scottish Building Standards Agency ( SBSA) provides a database of Approved Bodies (companies) and Approved Certifiers (individuals eligible to submit certificates) for work requiring a building warrant. Councils can access this via the SBSA website at http://www.sbsa.gov.uk.
Making the assessment
14.14. The flow-chart below will help guide an assessor through the process of examining an electrical installation. Some of the terms used may be unfamiliar to assessors, and these are explained later in the chapter.
14.15. An assessor should consider the information set out below when thinking about each of these questions.
14.16. The purpose of assessing an electrical installation against this element of the tolerable standard is to determine whether it is unsafe to use. The most effective way of doing this is to have a competent person carry out a periodic inspection and produce a report on the condition of the installation. Assessors should try to find out if the house has been inspected and tested and, where possible, obtain a copy of the report.
14.17. However, the electrical installations in most private houses will not have been inspected and tested and it is not practical for local authorities to instruct a competent person to carry out a periodic inspection for every house assessed against the tolerable standard. The guidance in this chapter will help assessors identify houses that are most at risk of having unsafe electrical installations.
14.18. The first part of the assessment requires an assessor to walk through the property and look at all accessible electrical components and wiring. This includes components such as the consumer unit, all switch units, socket outlets and light fittings, and any visible wiring. Where possible and safe to do so, an assessor should look in any accessible under-floor and roof spaces and look at any wiring or components within these areas.
14.19. Assessors should not remove any light switch or socket outlet covers to look at the condition of concealed wiring. If required, this should only be carried out by a competent person.
Indicators
14.20. An assessor should consider all the available information to help him/her decide if the house meets the tolerable standard. He/she should look for indicators that the electrical installation is unsafe. Examples of indicators that an assessor may see are given in the tables below. These are split into the following two distinct groups:
Table A: indicators that on their own mean that the installation is unsafe; and
Table B: indicators that mean the installation is at risk of being unsafe.
Table A indicators
14.21. The table below includes a number of indicators that an assessor might find when looking at an electrical installation in a house. Table A indicators represent defects and deficiencies in an electrical installation that, if identified during an inspection and test by a competent person, would mean the installation is unsafe for continued use. Finding any Table A indicator usually means the house is below tolerable standard. If an assessor is unsure if the electrical installation is unsafe, he/she may wish to ask a competent person to make this judgement.
Look for: | Unsafe because: |
|---|
Absence of a consumer unit | Installation may have no isolating switch, fuses or circuit breakers. This is a clear fire and shock risk. |
Connected rubber sheathed wiring (black coloured round cables) | This type of old rubber cabling is susceptible to deterioration leading to exposed or crossed wiring. |
Connected lead sheathed cabling (wires with a lead outer coating) | Lead coated cabling ceased to be used for electrical wiring in the 1930s. If it is still in use in a house it is likely to have deteriorated and is at high risk of breaking. This is again a fire and shock hazard. |
'Do not use' notice on consumer unit, or serious fault detailed in a recent electrical engineer's report | Electrical installation may recently have been identified as unsafe by an electrical engineer. |
Taped joints, exposed or loose wiring | Risk of fire and lethal shock. |
Wall light switches in bathrooms (not cord-pull type) | Risk of lethal shock from use with wet hands. |
Socket outlets in bathrooms (excluding shaver sockets) | Risk of lethal shock from using a socket outlet with wet hands, or accidental immersion of an appliance ( e.g.TV or hair dryer) in water. |
Charring or scorches around socket outlets, or sparks from light switches | May indicate that component is faulty and poses risk of fire and lethal shock. |
Table B indicators
14.22. The indicators detailed in the table below may, individually or collectively, demonstrate to an assessor that the electrical installation in a house is at risk of being unsafe. Assessors must take into consideration all available evidence and use their experience and judgement to decide if they should have the installation inspected and tested by a competent person to determine if it is safe to use.
Look for: | At risk of being unsafe because: |
|---|
Unprotected cable mounted on the surface of walls, floors etc | Surface cabling is at risk from accidental impact damage, and this can pose a danger of shock or fire. May also indicate electrical work has been carried out by an unskilled electrician. |
Occupier informs assessor that consumer unit or a socket outlet frequently trips or fuses | May be a wiring fault in the circuit, and this can mean there is a risk of fire. |
UPVC cable on exterior of house | Unsuitable for external use. May indicate electrical work has been carried out by an unskilled electrician. |
Plug-in testing device indicates fault | Testing devices that plug directly into a socket outlet may indicate a wiring fault (note - these devices test for certain faults. If the device does not indicate a fault, this does not mean that the electrical installation is safe) |
Metal consumer unit with ceramic wired fuses | Indicates the unit is more than 25 years old and may no longer be suitable. |
Installation is over 30 years old. May be indicated by brown plastic switch units and socket outlets, or round-pin (2-pin) socket outlets | Any electrical installation over 30 years old is at risk of being unsafe if it has not been upgraded or recently tested. |
Periodic Inspection Report
14.23. If an assessor decides that a house is at risk, he/she should arrange for a competent person to carry out a periodic inspection of the electrical installation. In such cases, an assessor should base the decision on whether it meets the tolerable standard primarily on the information contained within the inspection report. The Periodic Inspection Report will state the overall condition of the electrical installation. If it is described as "satisfactory", no remedial work is required to make the installation safe to use. If it states that the installation is "unsatisfactory", the observations made by the electrician and the recommendations for action to be taken will be detailed in the report.
14.24. Each observation and recommendation is attributed a code (1-4) depending on the seriousness of the deficiency. Code 1 means that the electrical installation is dangerous, or potentially dangerous, to use and requires urgent attention to make it safe. A house with an electrical installation that is judged to be unsatisfactory because of a Code 1 deficiency is below tolerable standard.