Mike Lawrence of Havells outlines how you can create more room and simplify the installation – by using a smaller size electronic RCBO.
The Third Amendment to the 17th Edition Wiring regulations (BS7671), which became effective on 1 January 2015, has once again put the focus on the importance of firesafety in electrical installations. Much of the initial market attention has been focused on the requirement for consumer units and similar switch gear to be manufactured from non-combustible material (or to be enclosed in a cabinet/enclosure constructed of non-combustible material) where used in ‘pure’ domestic dwellings. A continued focus on the use of RCDs is intended to drive better practice and more efficient end solutions, that are safer and create as little inconvenience as possible to the end user, when this RCD technology is called on to operate under a fault condition.
“The introduction of the original 17th Edition wiring regulations (BS7671) also created a dramatic increase in the use of RCBOs in commercial and industrial installations.”
One of the most significant developments to come out of original introduction of the 17th Edition Wiring Regulations, relating to electrical distribution boards, was the ‘Dual RCD’ or ‘High Integrity’ consumer unit format for domestic dwellings, which was intended to increase the protection of end users afforded by RCD technology whilst considering the impact and disruption to end users, in the event of a Earth leakage fault. Although this has undoubtedly improved electrical safety in the home, the concept and practice of protecting multiple end loads circuits through multiple MCBs backed up by just two RCCBs (RCDs) still translates into multiple end loads being disconnected by the operation of the RCCB in the event of an earth leakage fault. This can have a significant impact on end users in the event of a fault and can add a level of complexity to fault finding. An RCBO combines the short circuit and over current protection afforded by MCBs with the Earth leakage protection of RCD technology in a single unit.
The introduction of the original 17th Edition wiring regulations (BS7671) also created a dramatic increase in the use of RCBOs in commercial and industrial installations. The benefits of this combined MCB/RCD technology in RCBO format has been less popular in domestic dwelling applications, mainly due to the lower cost of the ‘group protected solutions’ achieved through the introduction of the Dual RCD consumer unit distribution board. There is however a trend towards an increase in the use of RCBOs in consumer units, driven by the obvious end user benefits this technology brings, combined with the more aggressive market pricing of the technology. However, whether installed in commercial, industrial or residential applications, the increased space requirements and complexity of installing RCBOs are the same. RCBOs traditionally take up a lot more space than an MCB, as well as having a neutral cable and earth reference wire to manage, creating a real challenge to achieve a neat, safe installation that is easy to access for testing purposes and any future modifications.
Compact RCBOs
Havells understood the safety benefits offered by RCBOs and also the issues associated with the larger size of available devices. As a result, the company has developed a Compact RCBO range with all the same operational functions as the standard unit, but at a much smaller size. Unlike standard RCBOs, the compact range has been designed to simplify installation and have less impact on cabling space in electrical distribution boards. The Compact RCBOs maximise cabling and termination space due to an impressive 25mm shorter footprint and being only 12mm longer than an MCB. Furthermore, the range is fully electronic so requires no separate earth reference wire – an additional benefit for simplifying and speeding up installation within a distribution board.
The Compact RCBOs are available in a range of sizes from 
6A to 32A, in both B and C trip curves, with breaking capacity ratings of 10kA and 6kA to suit most applications. Earth leakage sensitivity is 30mA. The new Compact RCBOs are part of the Havells Homesafe Pro Residential solutions range and the Powersafe range of industrial and commercial circuit protection products, which continue to push innovation in product design, to not only create new products which complement existing requirements, but also offer installer friendly features without compromising safety or quality.
