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It is the intention of this article to explain simply how to select the correct cross-sectional area of cables with particular single-phase loads in mind. I’ll refer to the tables in Appendix 4 of BS 7671, although these tables are reproduced in Appendix 6 of the IEE On Site Guide. We’ll assume that the overcurrent protective device will be providing fault current and overload current which is the normal situation.

What are earthed and unearthed systems? What are the requirements of BS 7671? What are the advantages and disadvantages of the various types of earthing systems? This article, which is based on IEE Guidance notes, is intended to provide information that it is hoped will prove helpful. BS 7671 lists five types of earthing system: TN-S, TN-C-S, TT, TN-C, and IT. T = Earth (from the French word Terre) N = Neutral S = Separate C = Combined I = Isolated (The source of an IT system is either...

Questions relating to the requirements for supplementary equipotential bonding are frequently asked; a very common one is where should it be installed. This article looks at the requirements for supplementary equipotential bonding in BS 7671:2008, where supplementary equipotential bonding should be installed and offers help on the process of evaluation.

British Standards for Free BS5839-1 and BS5839-6 (British Electrical Standards) British Standards are expensive, but there's a way you can use your library to access them free of charge. And you are allowed to take notes. You can't copy whole pages etc - that's breach of copyright. But you can take lots of notes. Here's a list of UK libraries with copy's of the british standards in electrics. Libraries in the UK with BSOL UK Libraries with access to British Standards Company City Post...