Design & Installation

Armoured cable supplies to outbuildings

ELECSA consistently receives enquiries relating to supplies to detached outbuildings of domestic premises, such as garages, sheds or home-offices. This article addresses the questions which typically arise where such a supply is provided by an SWA cable buried in the ground, in particular: • Can the armouring be used as a circuit protective conductor?• What are the equipotential bonding requirements?• What are the particular requirements where PME conditions apply? Armouring…

Electrical installations for greenhouses

Except for those requirements applying only to locations where livestock is kept, the requirements relating to agricultural and horticultural premises given in Section 705 of BS 7671 apply to the electrical installation in any greenhouse, whether it is a large commercial greenhouse or a small garden greenhouse. Electrical installations in such locations are considered by BS 7671 to warrant special attention due to the increased risk of electric shock. The increased risk…

Power factor correction – What is it? Why is it required? How is it achieved?

Power factor basics: Power quality is essential for efficient equipment operation, and power factor contributes to this. Power factor is the measure of how efficiently incoming power is used in an electrical installation. It is the ratio of active to apparent power, when: Active Power (P) = the power needed for useful work such as turning a lathe, providing light or pumping water, expressed in Watt or KiloWatt (kW) Reactive…

Keep an open mind

Don’t look backwards, the saying goes. You’re not going that way! writes Simon Johnson, Sales Engineer, Theben and KNX UK board member As an apprentice you are in the great position of being able to learn the theory and fundamentals of your trade in the classroom whilst picking up the necessary hands-on skills you need on the job. You need to have an eye for the future and be prepared.The…

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…

The process for safe isolation

In this video Steven Devine, author of the IET Student’s Guide, walks us through the process of safe isolation.