Additions or Alterations – When/Where Are You Allowed To Make Them?

Additions or Alterations – When/Where Are You Allowed To Make Them?

Compliance advice from the experts at NICEIC.

Most domestic electrical installations will require one or more additions or alterations during their lifetime. Where such work is proposed, it is important to confirm the safety and adequacy of the existing installation before the work is undertaken.

Additions or alterations to typical domestic installations generally range from relatively minor works, such as the addition of a socket-outlet to an existing final circuit or the repositioning of a lighting point, to those involving the addition of one or more new final circuits and/or the replacement of a consumer unit. However, irrespective of the work proposed, the safety of the existing electrical installation needs to be assessed to confirm that it is safe for the work to proceed.

Regulation 132.16 of BS 7671 requires that no addition or alteration, temporary or permanent, is made to an existing installation, unless:

  • the rating and the condition of any existing equipment, including that of the distributor, are adequate, for the altered circumstances, and;
  • the earthing and bonding arrangements, if necessary for the protective measure applied for the safety of the addition or alteration, are adequate.

Where inadequacies, such as mechanical or thermal damage, are identified with the intake equipment and its enclosures, the person ordering the work should be advised to inform the distributor and/or meter operator, as appropriate.

Where a dangerous or potentially dangerous situation is discovered in the existing installation (such as the absence of protective bonding where the method of fault protection is ADS), the addition or alteration should not proceed and the client should be advised immediately of the safety issue.

To satisfy the duties imposed by the Electricity at Work Regulations 1989 the details of the safety issue and action required should be given to the client (or person acting on their behalf); this may be achieved by the issue of an Electrical Danger Notification form (see Fig 2).

Whilst compliance with Regulation 132.16 may confirm that it is safe for the addition or alteration to proceed, depending on the particular installation and the nature of the addition or alteration, there may be a range of practicalities that need to be discussed with the client. For example, new circuits may be required but the existing consumer unit may have no spare ways or may not be a suitable type of unit to install an RCD or RCBO.

As cables are normally concealed in domestic installations additional protection will normally be required. Especially, considering the requirements of Regulation 411.3.3 for socket-outlets not exceeding 32 A and supplies to mobile equipment intended for use outdoors, and Regulation 411.3.4, which applies to circuits supplying luminaires within domestic premises.

Whilst the RCD providing additional protection may be installed at the point where the new work is connected to the existing installation, if a number of circuits require additional protection it may be more beneficial to upgrade the existing consumer unit. These types of practical options should be discussed and agreed with the client before the work is undertaken.

Comments on the existing installation

Whilst there is no requirement to carry out a formal inspection of parts of an existing installation unrelated to the work to which the certificate applies, any defects observed in parts of the existing installation, unrelated to the addition or alteration being carried, that may give rise to danger, should be recorded on the certificate under ‘Comments on the existing installation’ (Regulation 644.1.2).

Any defect relating to the circuits or equipment that from part of the addition or alteration must be corrected before the new work is put into service. If there is reason to believe that unrelated parts of the existing installation are in an unsatisfactory condition, you should recommend to the client that the installation (or the appropriate part of it) is inspected and tested, and an Electrical

Installation Condition Report is issued.

Certification of an addition or alteration

On completion of an addition or alteration including the replacement of a consumer unit an Electrical Installation Certificate (EIC) or Domestic Electrical Installation Certificate (DEIC) should be issued to the person ordering the work. The certificate is issued to provide a formal declaration that the work has been undertaken in accordance with the relevant requirements of BS 7671 (current at the time the work was undertaken) and does not impair the safety of the existing installation. Where an addition or alteration to an existing installation does not include the provision of a new circuit a Minor Electrical Installation Works Certificate (MEIWC) may be issued (Regulation 644.4.201 refers). A separate MEIWC should be issued for each circuit that has been added to or altered.

Compliance with Part P of the Building Regulations

In addition to the certification required by BS 7671, for certain electrical installations deemed ‘notifiable’ under Part P, a Building Regulations Compliance Certificate must be issued to the owner/ occupier of the premises to confirm that the work complies with the relevant parts of the Building Regulations.

In accordance with Paragraph 2.5 of the 2013 Approved Document for use in England, where electrical work is carried out in a dwelling or its surroundings, notification must be provided for the following:

  • installation of a new circuit,
  • replacing a consumer unit, or
  • an addition or alteration to an existing circuit in a special location.

Note: For work undertaken in Wales, the 2006 edition of Approved Document P (incorporating 2010 amendments) remains applicable and so work in Wales should continue to be notified according to that document. For Approved Documents refer to:

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