Three 18th exam questions that cause problems… 1) What is the minimum dimension for a round diameter bonding ring network conductor when considering measures against electromagnetic disturbances? 25mm, 10mm, 8mm or 3mm It’s 8mm – take a look at 444.5.3 (ii) 2) Which one of the following external
READ MOREFor our 18th Edition online courses here at the-regs.co.uk and partPtrained.co.uk we currently have 28 City & Guilds exam venues and 7 EAL exam venues – “Covering the whole of the UK, from Exeter to Aberdeen and everywhere in-between!” Recently, I have noticed that some training centres are
READ MOREAs current flows through a conductor due to it’s electrical resistance it produces heat. If the current in the conductor increases then the heat also continues to rise and eventually we could reach a temperature which will cause permanent damage to the cable or possibly even a fire
READ MOREWhy on a TN-S earthing system is the maximum Ze given as 0.8 ohms by the supply authority when it’s often protected by a BS 88-3 100A fuse which has a maximum Zs of 0.38 ohms? This maximum value for Ze of 0.8 ohms for a TN-S earthing
READ MOREWithin domestic installations there are numerous regulations within BS 7671:2018 concerning additional protection through the use of 30mA RCDs… 411.3.3: Gives us additional protection via a 30 mA RCD for ‘general’ sockets, both indoor and outdoors. 411.3.4: Again 30 mA RCD additional protection for all lighting circuits. 522.6.202:
READ MOREHow an electric shock occurs… An electric shock occurs when a person becomes part of a circuit, with current entering the body at one point and leaving it at another. The two methods of receiving an electric shock are… Coming into contact with a normally live part (i.e.
READ MORE#1: Knowledge of Electricity… A good understanding of the basic principles of electricity is essential, from Ohm’s Law and resistors in series and parallel to power calculations and transformer theory. Including a good working knowledge of cable and protective conductor sizes as well as selecting protective devices their
READ MORESizes of main Bonding Conductors… This can be confusing as the size of the main bonding conductor differs depending on the type of supply. In a TN-S or TT system the main bonding conductor is in relation to the size of the main earthing conductor which is dependant
READ MOREConsumer units in new and modern domestic installations should contain Residual Current Devices ‘RCDs’ as well as circuit breakers. Either as combined RCD/circuit breaker devices ‘RCBOs’ which can get a bit expensive or alternatively and less expensive through the use of split load boards with usually two RCCBs
READ MOREThe most common cable found within a domestic electrical installation is the PVC insulated and sheathed Twin and CPC cable – also known as Twin and Earth. A PVC three core and CPC is also used on two-way lighting circuits, smoke detector interlinks, fans with timers and also
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