This page discusses the relationship between BS7671:2008 and BS7909:2008 in order to highlight the differences between; temporary electrical systems and electrical installations.

Standards:

BS 7909:2008 Code of practice for temporary electrical systems for entertainment and related purposes

BS 7671:2008 Requirements for electrical installations. IEE Wiring Regulations. Seventeenth edition

BS 7671 applies to the design, erection and verification of electrical installations, also additions and alterations to existing installations. Existing installations that have been installed in accordance with earlier editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading.

BS 7671:2008 includes changes necessary to maintain technical alignment with CENELEC harmonization documents.

BS 7671:2008 Requirements for Electrical Installations is intended to come into effect on 1st July 2008. Installations designed after 30th June 2008 are to comply with BS 7671:2008.

IET Wiring Matters Articles (Mostly to BS7671:2004):

• Mobile and transportable units
• Exhibitions shows and stands
• Temporary power for entertainment purposes
• Equipotential bonding
• Cables for temporary installations

Other Articles:

Section 711, BS7671:2008 and BS7909 - by Stewart Newlands

From BS7671:2008

"711.1 Scope. The particular requirements of this section apply to the temporary electrical installations in exhibitions, shows and stands (including mobile and portable displays and equipment) to protect users. Unless specifically stated, this section does not apply to exhibits for which requirements are given in the relevant standards.

This section does not apply to the fixed electrical installation of the building, if any, in which the exhibition, shows or stands may take place.

This section does not apply to electrical systems as defined in BS7909 used in structures, sets, mobile units etc as used for public or private events, touring shows, theatrical, radio, TV or film productions and similar activities of the entertainment industry."

As you have read the entertainment & production industry have opted to follow a code of practice that better suits their needs and established methods of working. BS7909 which is being updated to bring it closer to BS7671 and to provide more detailed guidance for things like large events with multiple temporary electrical systems and fixed installations, provision for bonding temporary structures and fixed structures in a common electrical environment and much more.

It should be noted however that the general scope of BS7671:2008 now includes: "110.1 (viii) construction sites, exhibitions, shows, fairgrounds and other installations for temporary purposes including professional stage and broadcast applications."

So where does this leave section 711?
Firstly I believe that, as part of a risk assessment and method statement process for a particular job the equipment or exhibit should be defined in reference to it's use according to either BS7671 section 711 or BS7909 as relevant.

Secondly, it is my interpretation that if the installation or elements primarily form a fixed or static display for use or occupation by non technical people then section BS7671:2008 711 should be used as the standard in the first instance and not BS7909. So a display with a few lights /av elements in the lobby of a theatre may well be an exhibition stand to BS7671:2008 section 711. Section 711 applies to set elements with fixed wiring installations and display cases etc.

Thirdly, Section 711.6 BS7161:2008 requires "The temporary electrical installations of exhibitions, shows and stands shall be inspected and tested on site in accordance with Chapter 61 after each assembly on site."

The new BS7909 divides things between simple activities using up to around 6kW of power and complex activities. BS7909 is written for kits of pre-tested and inspected modules joined using appropriate plug and socket devices. This is a clear distinction in the set up and assembly methodology used in the construction industry for permanent installations.

If there are electrical connections made on assembly by means other than plug and socket a decision should be made to test and inspect regardless of the standard being followed. Citing BS7909 is not a get out for inspection and testing on site it expects this to have been done in advance, and that conditions on location are taken into account, for example; if bonding is required it needs to be checked once in place.

Note: section 711 is directly related to CENELEC Harmonization Document 384.7.711 (2003) entitled: "Electrical installations of buildings -- Part 7-711: Requirements for special installations or locations - Exhibitions, shows and stands" the scope of which is; "Gives requirements applying to the temporary electrical installations in exhibitions, shows and stands (including mobile and portable displays and equipment) to protect users."

Stewart Newlands HNC, 2391-10, 2382-20, Electrician and NOEA representative for BS7909:2008

This website is published by Stewart Newlands