High voltage (HV) installations

Recent changes to the certification of prescribed electrical work in installations under the Electricity (Safety) Regulations 2010 have highlighted some uncertainties around existing certification requirements for HV installations.

There has always been a requirement to certify and inspect a HV installation. The significant changes introduced in 2013 for HV installations are the requirement for a certified design and the introduction of the electrical safety certificate (ESC).

The principle requirements that apply to HV installations under the Electricity (Safety) Regulations 2010(external link), including amendments, are:

  • All construction, testing and inspection done on HV installations (regulation 62) is required to comply with the provisions of regulations 34 and 39 to 46, which are regulations that also apply to works. This allows the alignment of the technical requirements for HV installations and HV works.
  • The construction of an HV installation is now required to be covered by a certified design as specified in regulation 58. 

The requirements for testing and certifying prescribed electrical work on HV installations are specified in regulation 64 where:

  • HV installations must be tested in accordance with regulation 38.
  • On completion the installer is required to provide a certificate of compliance (CoC) (regulation 65) for the work carried out as per the design and indicating this as required on the CoC.
  • An inspection is required (regulation 70(2)) by a registered electrical inspector that has not been involved in any of the installation work. A record of inspection (RoI) is to be completed (regulation 72) and the work must be lodged in the high risk data base (regulation 74(F)), as this work is categorised as high risk prescribed electrical work (regulation 6A).
  • An electrical safety certificate (ESC) must be issued when the connection is carried out (regulation 74A). When you have made the connection and are satisfied that the tests, such polarity and the like (regulation 38 (2)), are correct and it will be safe for use, sign off the ESC.
  • Connecting to the power supply is subject to the verification provisions of regulation 73A (2).