Design

What are the different types of circuit?

The key thing to remember when selecting the type of circuit for an electrical installation is the requirements stated in the IET Wiring Regulations. These are that: The number and type of circuits required for lighting, heating, power, control, signalling, communication and information technology, etc, shall be determined from knowledge of: Location of points of power demand. Loads to be expected on the various circuits. Daily and yearly variations in…

Taking the feed (supply) to a switch

In this video, Gary Hayers form Tresham College looks at the practice of taking a supply to a switch. This follows another tutorial where Gary explains 3-plate loop-in method. Student training aid for the connections required when the feed is taken directly to the switch. Also, how to wire two way and two way and intermediate switching. Video explains the connection required within switches. The circuit is wired in…

How do I determine an extraneous conductive part?

This article provides some simple guidance on how to identify extraneous conductive parts to help you avoid the unnecessary installation of protective bonding conductors. It should be appreciated that exposed metallic parts not forming part of the electrical installation are not always extraneous conductive parts as defined in Part 2 of BS 7671. Therefore, as explained in this article, to avoid the unnecessary installation of protective bonding conductors, it is important…

An introduction to earthing and bonding

Earthing and bonding are two very different, but often confused, methods of preventing electric shock. The principal of earthing is to limit the duration of touch voltages if you were to make contact with an exposed conductive part. The earth creates a safe route for the current to flow instead of causing electric shock. The purpose of bonding is to reduce the risk of electric shock if you find yourself…

An overview of cable management systems

There are a wide variety of containment systems available to organise and store cables within an installation. They tend not to be used exclusively for a particular type of wiring system, and the containment system chosen is often as much decided by the budget and practical considerations of the building it is being installed in as the cabling type itself. Fixings in cable management With such a range of cable…

The height requirements for electrical equipment in dwellings

This article will consider the various requirements relating to the mounting heights of electrical equipment in dwellings. The aim of this article is to explain the requirements of BS 7671, Part M of the Building Regulations for England and Wales and BS 8300: 2009 (Design of buildings and their approaches to meet the needs of disabled people) relating to the mounting heights of electrical equipment in dwellings. In addition, the article will include…