SPECIAL FEATURE
CIRCUIT PROTECTION & SWITCHGEAR
ELECTRICAL SAFETY FOR NEW HOMEOWNERS Last August, the rules on permitted developments were relaxed, allowing more types of extensions to be carried out without full planning permission. If the work can be considered as ‘material alteration’ to the property according to the Building Regulations, rewiring is likely to be needed, including upgrading the consumer unit. Ashley Clements-Smith, Senior Channel Lead from Honeywell, discusses which devices should be considered when installing new consumer units under these circumstances.
C Metalclad CP consumer unit
hanges to Permitted Development Rights were introduced last August, which meant homeowners could do more with their homes without needing to go through the full planning process. If the modifications involve major remodelling work on the property, the works will need to comply with Part P of the Building Regulations and meet BS 7671:2018 – the 18th Edition Wiring Regulations. If the amount of work involved is significant enough to be considered as ‘material modifications’ by the Building Regulations, it is likely that rewiring will be needed for part, if not all, of the property, including upgrading the consumer unit. In anticipation of the second amendment to the 18th Edition regulations which are currently under consideration, what should electrical contractors look for in a consumer unit to provide circuit protection that is futureproofed?
Mod cons
“It is worth installing products with circuit protection to help future-proof extension projects”
Over the past 50 years, the industry globally has moved away from traditional linear loads from electrical products such as incandescent lighting to power devices which have switch mode power supplies. Where the former take their power along the whole current wave form so that the load is linear, the latter take different chunks of current out of the sine wave. This distorts the waveform, which causes peaks and troughs. Newer type-A Residual Current Devices (RCDs) like those featured on Honeywell’s Metalclad CP can detect DC fault currents, whereas older type AC RCDs are less likely. Although the use of these type-A devices is not mandatory, they are now becoming increasingly specified by consultants and contractors and are recommended in the 18th Edition to provide better protection. Most modern homes have appliances such as washing machines, dishwashers and fridges, and with mod cons such as LED lighting, lighting and heating controls, and induction hobs likely to be installed as part of new extension works, type-A RCDs should be considered. Type A RCDs are mandatory for circuit protection for sites with electric vehicle charging stations.
Hidden defects
Surge protection When lightning strikes, voltage can be induced onto the local power line, causing a sudden rush of voltage entering properties. A Surge Protection Device (SPD) is designed to absorb this voltage to protect properties and their electrical equipment. It is not mandatory, but a recommendation in the 18th Edition, depending on the probability of lightning strikes in an area. SPDs are offered as an optional extra in the Honeywell Metalclad consumer unit. Although a decision on possible amendments to the 18th Edition wiring regulations will not be made until early 2022, it is worth installing products with circuit protection to help future-proof extension projects. This way, customers can be reassured that their properties have been protected to the latest industry requirements and beyond. Honeywell, hwll.co/Metalclad
scolmore.com
An AFDD is an intelligent device which monitors the power system to detect dangerous arcs. These types of arcs could be caused by issues like problematic connections in a faulty piece of equipment, insulation defects in cables, damaged cables or loose terminal connections. Dangerous arcs generate heat and, if these go undetected, they could lead to fires in electrical equipment or the fixed wiring.
When an unsafe arc is detected, AFDDs disconnect the circuit. They are programmed to tell the difference between safe and dangerous arcs so that normal ones such as those caused by switching cycles do not trip the AFDD. Although these are not mandatory in the current 18th Edition, it has been proposed to make them so in the next amendment, to provide better protection against fires caused by arc faults in AC final circuits. AFDDs can be installed in distribution boards and consumer units. Two AFDDs can be included in the Honeywell Metalclad CP consumer unit so that households can be protected from the dangers of these electrical faults, which are often unknown until it’s too late.
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Consumer Units Elucian by Click® brings to the market a comprehensive Consumer Unit and Circuit Protection range. It covers a broad range of installations and offers a number of features and benefits that will enhance the products’ convenience, flexibility and safety properties.
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16/06/2021 11:48:12 /electricalcontractingnews
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