What is a certified design and why would you need one?

A certified design provides accountabilities and obligations on the designer and provides the installer or electrical contractor with a document to mount a defence if things go wrong.

  • Certification

Electrical design work

The Electricity (Safety) Regulations 2010 apportion responsibility for all aspects of electrical work from electrical design, installation and inspection to the person most responsible. All this work requires some form of verification or certification of its safety and compliance.

A certified design provides accountabilities and obligations on the designer and provides the installer or electrical contractor with a document to mount a defence if things go wrong.

Although the drafting of an electrical design is not prescribed electrical work and any competent person is legally able to design, an electrical installation there are penalties under the Regulation 14(external link) of the Electricity (Safety) Regulations 2010 if the design is electrically unsafe. Designers and companies can be subject to prosecution.

An "as built” are not certified designs

A certified design is not the same as an “as built”. Typically, an “as built” is finalised once the installation is fully completed and incorporates all the resulting changes and modifications made by either or both the electrical contractor and designer during the course of the project in the final set of documents.

A certified design on the other hand must contain certain prescribed information and could include a complete dossier of documents that specifies, in detail, all the relevant information to enable the installation to be safety installed, tested, certified and inspected by the contractor and inspector.

It is important to note the electrical contractor cannot alter or change the certified design under any circumstances without first consulting the designer. Any changes need to be signed off by the designer and incorporated in the design. If the installer alters or changes the design then it is not a certified design and the contractor may be held accountable if things go wrong or the design is unsafe in any way. Therefore, it is important to understand the distinction between an “as built” and a certified design, they are not the same thing.

Where are certified designs used?

The Electricity (Safety) Regulations 2010 mandate certified designs in high voltage installations and any installation installed in accordance with Part 1 of AS/NZS 3000.

Certified designs may be required for specialist equipment and installations that do not comply with the prescribed installation practices of AS/NZS 3000 part 2 or its specified standards. A certified design may influence or direct the selection of electrical and fittings, and its installation, or maintenance. Examples of a certified design include an architect's drawing or an engineering design that shows the location of fittings, because these drawings or designs influence the safety of a completed installation. A certified design may also be used for the whole or only for part of the installation.

However, a certified design could also be intended or drafted for any other low voltage installations in compliance with AS/NZS 3000 part 2. For example, this could include and is not limited to residential, commercial installations, schools etc.

What is a certified design?

A certified design is a complete design installation package in its own right. An electrical contractor should be able to use the design from the beginning of the project to its completion, following only the design specifications and requirements. There is no discretion for the installer or inspector to alter or modify any specifications, or use their own interpretations to achieve the desired outcomes. Any alterations need to be completed, documented and signed off by the designer.

For a design to be considered certified when it is being relied on to install, test, certify, inspect and connect installations, it must establish compliance with all NZ legislation requirements. It must be electrically safe and compatible with the electricity supply it is connected to and not affect the safety of any other installation or part installation.

A certified design for an electrical installation or part installation should specify all relevant information for its safe installation, assembly and operation. This may include associated drawings, installation techniques, and specifications for fittings and appliances. It must also contain the standard or standards that it relies upon to achieve safety and compliance.

It is very important the design documentation must also include the following:

  • Clearly identify the designer or person responsible for the design, with the date and their signature.
  • The location or proposed location.
  • Reference what, if any, standard (s) the installation complies with or is intended to comply.

A certified design is part of the necessary risk management framework and enables the responsibilities, liabilities, and accountabilities of all parties that influence safety of completed work to be identified. Other parties (for example, installers, electrical contractors and inspectors) are entitled to rely on, acting in good faith, certified designs to establish compliance.

If a design is not in accordance with these requirements, then it is not a certified design and cannot be relied upon by the installer or electrical contractor.

Regulation 58(external link) has further details on what legally constitutes a certified design.

Who can create a certified design?

These can be created by a single person or persons that are qualified and competent in the area they are designing and may include:

  • An electrician who will construct the installation.
  • An electrician independent from the construction.
  • A competent person (such as an architect)
  • An engineer.

Anybody who designs or supervises the design of works, installations, fittings, or appliances must ensure that the finished design will be electrically safe when it is constructed, installed, or manufactured.

Regulation 14(external link) makes it an offence to complete a design — including supervision of the design process — which if constructed would not be electrically safe.

Working with certified designs

Ensure the design is a certified design

Firstly, identify the design is in fact a certified design based on the legislative and safety requirements that it is signed and dated in compliance with Regulation 58(external link) and a complete design package in its own right.

Management and competence

Before commencing work, electrical practitioners should be aware they are working to a certified design. Electrical contractors should have in place processes to manage and communicate with the designer about any changes required to facilitate the construction of the installation. Any changes or alterations to specifications or fittings need to be agreed to by the designer and then incorporated into the design. These changes will then constitute part of the certified design and the accountability for them remains with the designer not the electrical contractor.

It is important that electrical installers have the required levels of competence and effective management processes in place to ensure compliance with the design and associated specifications.

Inspection is required

It is very important that electrical inspectors who are inspecting the installation are fully conversant with the certified design to ensure the work they inspecting has been installed to the design specifications and any other associated requirements. Inspectors must have the required skills knowledge and competencies to carry out this inspection work.

Accountabilities and responsibilities

The designer is responsible for ensuring the final installation when completed to the specified design, will be electrically safe to use and operate as specified.

The electrical contractor, if acting in good faith, is able to rely on the certified design for the completed installation to be compliant and electrically safe if it has been installed to the design specifications and requirements.

Certification requirements

The certified design must be attached to the certificate of compliance or have an electronic link to the certified design on the certificate of compliance.

Quick guide to certified design

Certified design quick guide

Published 3 October 2018