Sparks Electrical News February 2022

DISTRIBUTION BOARDS, SWITCHES, SOCKETS AND PROTECTION

10

Create a smart home. Here’s how

Reverse feeding circuit breakers: What are the risks? T he purists amongst us would not ask this question they simply would never reverse feed a circuit breaker. But there will come a time this option appears the only real solution! By reverse feed we mean the incomer side is on the bottom or tradi- tional load side. Some sectors have always used this approach as the standard norm, for example, the supply authorities have followed a reverse strategy for many years whether it is approved or not. The main incomer into DB is often also more easily wired in such a fashion, especially if copper busbars are used. But let us explore this topic further. During product certification the circuit breaker will be tested in the conventional manner. This is the standard approach but there is an al- lowance to do part of the test in the reverse manner if requested to do so by the manufacturer. If all tests are positive the test report will indicate the results. The main tests are that of short circuit function. The best result would be no degradation for direction, but it could be that for reverse the short circuit may be lower than forward. Not an optimum result but still a pos- sibility. Besides the report the circuit breaker will indicate this option by not having LINE/LOAD marked on the unit itself. Failure and non-test will require the circuit breaker to be marked according with LINE/LOAD. So, a modern new circuit breaker from a reputable supplier without marking could be used in reverse method if not indicated to the contrary. Is has also been more common than in the past to do these reverse tests as the norm. But what about the older generation products possibly fitted already on site? Clearly, if indicated LINE/LOAD this should be followed to the letter then. In terms of the required electrical legislation the reverse option would have to very prominently marked to avoid confusion! There is one other consideration which could add to the higher risks of damage in the longer term, however, even if approved. There may be more of the electrical circuit being livened in the re- verse fashion due to the circuit breaker design, e.g. MCB’s and MCCB’s typically. That means that during even the OFF state the metal compo- nents are still live internally. Really this concept should not be applied to smaller panels with MCB’s (even if manufacturer allowed) as the levels of electrical com- petence are not stable for these sites and there is not a very effective method to indicate this approach as compared to large DB’s! If the site conditions over time allowed for pollutive deposits which reduced insulation levels this may result in an internal short developing. This has been noted before and damage to the circuit breaker is very extensive and total write off generally. Summary So, in summary then yes, it is possible, but the additional risk/s must be considered. Contact your supplier if in doubt! For EL types this may not be possible even from the same model types as well as DC specific circuit breakers. Flack has recently retired from industry and believes he still has valuable in-depth knowledge of the South African electrical landscape due to wide experiences gained in his 45+ years working career. He is keen to explore the training arena so that this can be passed on to the current youth so as to benefit their practical ability in the electrical field. In these trying COVID-19 times, Flack can provide online training to keep your staff up to date on all aspects of circuit breaker deployment. Email kevin.flack@outlook.com By Kevin Flack

S mart homes are increasing by 18% each year in South Africa and are ex- pected to reach 2,5-million households in 2025. Today’s new normal has created ways for us to use our homes as boardrooms, a work zone, an entertainment centre, a class- room, and even a tranquil refuge. And smart homes can help us play multiple roles thanks to the use of an app. Remote and hybrid working arrangements have become the norm and that means we are spending more time at home than ever before. “Our homes are having to work harder and their occupants are even more stressed – adding to the household demands and pressure,” says Larry Barnes, product man- ager at CBI-electric: low voltage. “South Af- ricans are looking for convenience and flex- ibility, and that’s exactly what a smart home can deliver.” A basic smart home installation can automate security and indoor lighting, as well as a geyser, pool pump and even an irrigation system which can be scheduled according to the weather. Homes can be set p easily to provide comfort and control while saving time, energy andmoney. Often associated with costly high-tech de- vices, today’s smart home is affordable and easy to implement thanks to locally manufac- tured products. The Astute Range from CBI- electric: low voltage allows South Africans to add smart home components to households that can tailor everyday living experiences. Controlled directly from a smartphone and/ or tablet, the range includes the Astute smart controller, isolator and smart plugs which can be managed with the CBI Home app. The products allow users to turn various appli-

ances into ‘smart’ appliances by connecting them to an Astute Smart device. For example, various appliances that are connected to one of these devices can be controlled, monitored and scheduled remotely via the app. Household items such as underfloor heating can be set according to ambient outside tem- perature and time of day – effectively giving you climate control. If you’re trying to control screen time for your kids, you can connect your TV to an Astute Smart Plug (ASP) which allows it to be turned off after a set period of time. The ASP can also be added to your bedroom so you can schedule charging stations for your phone and automatically turn off an electric blanket. These smart devices can also monitor the energy consumption of appliances such as dishwashers, fridges and washing machines. Smart switches also provide users with great- er control over power consumption in rental properties and holiday homes. The Astute Smart Controller and the Astute Smart Plug are listed at R348, and the As- tute Smart Isolator is listed at R417 (ex VAT). Please note that distributor and retailer prices will vary. The range is available from leading homeware stores. About CBI-electric: low voltage Established in 1949, CBI-electric: low voltage is a manufacturer and supplier of quality low voltage electrical distribution, protection, and control equipment. Previously known as Cir- cuit Breaker Industries or CBI, the company specialises in the design, development, and manufacturing of circuit breakers, residential current devices, surge protection, wiring ac- cessories, and metering products.

Larry Barnes, Product Manager at CBI-electric: low voltage.

Head quartered in Johannesburg, South Af- rica, the company is a subsidiary of renowned JSE listed industrial group Reunert, with inter- national operations across Africa, Asia, Aus- tralia, Europe, and the USA. CBI-electric: low voltage can be found in almost every home and has firmly become a market leader over the last 72 years while supplying products to authorities, utilities, manufacturers, commercial property devel- opers, industrial, mining, telecommunications and general power distribution applications. In 2021, the brand launched its smart IoT (internet-of-things) home automation range, called the Astute Range.

Enquiries: www.cbi-lowvoltage.com/astute

Fluke’s 1664 FC Installation tester with Fluke Connect ® G rowing concern for public safety and the increasing complex- ity of today’s fixed electrical installations in domestic, com- mercial and industrial premises places extra responsibility on

lessly via smartphone directly from the field. They are lightweight, and feature a unique ergonomic ‘curved’ form that, when carried by the neck strap, makes operation in the field more comfortable. • Work safer, protect the installation under test, share results The Fluke 1664 FC is the only installation tester that protects connect- ed appliances from damage during insulation tests, and allows us- ers to share test results wirelessly by smartphone with coworkers or customers. • Insulation PreTest The Fluke 1664 FC Installation Tester is also the only tester with patent pending “Insulation PreTest”. If it de- tects that appliances are connected to the system during test, it will provide a visual and audible warning and stop the insulation test, avoiding potentially serious/costly mistakes and eliminate ac- cidental appliance damage. • Fluke Connect®, ShareLive™ calling and Fluke Cloud™ storage ShareLive™ video calls Users save time by eliminating data en- try by wirelessly syncing measurements directly from the 1664 FC and share with a remote team using Fluke Connect®. Having access to measurements simultaneously at the inspection site and the office allows faster decision making and real time col- laboration between team members. Cloud storage allows users to retrieve stored results whether in the office or out in the field, to make urgent decisions in real time. Data can also be imported into Fluke DMS to process and generate certificates. The Fluke 1664 FC is part of a growing system of connected test Tools* and equipment maintenance software.

electrical test engineers who are charged with verifying conformity to South Africa’s Certificate of Compliance (COC) safety standards. South Africa’s electrical contractors are well versed in the verifica- tion requirements of the COC, and that the audit should be carried out in the following sequence: 1. Visual inspection 2. Testing of the following: • Continuity of protective conductors. • Insulation resistance. • Protection by separation of circuits. • Foor and wall resistance. • Automatic disconnection of supply. • Polarity. • Functional performance. In addition to this the following tests are under consideration: • Electric strength test; • Voltage drop. The basic requirements for test equipment used in installation testing consists of general requirements for test equipment, specific requirements for combined measuring equipment and the specific requirements for measuring/testing: 1. Insulation resistance. 2. Loop impedance. 3. Resistance of the earth connection. 4. Resistance to earth. 5. RCD performance in TT and TN systems. 6. Phase sequence. 7.Insulation monitoring devices for IT systems . The Fluke 1660 Series Multifunction Installation Testers are meas- uring equipment which fully fulfil the requirements as described above, and the three different models in the series comply with spe- cific parts of this norm. They are specifically designed to carry out the tests specified, and all local standards and regulations in the safest and most efficient way. Comtest is offering Fluke 1660 Series Installation tester with Fluke Connect®, which includes the 1664 TM Installation Tester - the only installation tester that helps prevent damage to connected appliances during insulation tests, and also allows users to send test results wire-

Enquiries: www.comtest.co.za/Products/Product-Details/fluke-1664-fc- multifunction-installation-tester

SPARKS ELECTRICAL NEWS

FEBRUARY 2022