Your browser does not support JavaScript!

List of Electrician blogs

  1. Home
  2. List of blogs

Testing for optimum solar panel orientation

New research has suggested that panels function more efficiently by facing East-West, while the majority of UK panels face South, so the question is now whether the solar panels on over half a million buildings in the UK could be facing the wrong way. Taking into account the time of day when peak PV output is produced on South-facing panels, this is usually during low consumption periods in the middle of the day, when people are typically at work. Therefore most of the energy generated is fed to the grid at a feed-in tariff that is considerably lower than that paid by the consumer. The real energy savings benefits from solar panels accrue by using the energy generated and not by exporting it to the grid. This applies particularly during morning and evening demand peaks so according to some schools of thought, panels should be oriented both East and West. Germany is now installing East-West facing panels and the question is whether the UK will now follow suit, because if panels are to be mounted in both Eastern and Western orientations, only half of them will be operating at full irradiance during their morning and evening peaks. Therefore, there is a need to measure irradiance at the proposed location to determine optimum panel placement and orientation. Then when the solar installation has been completed, it needs to be tested. This requires both training and instrumentation. Training Site evaluation is one of the first steps that need to be undertaken for effective solar PV generation and this requires thorough training. Inclination, orientation and shading are the three main site factors that influence the performance of a PV installation. While drawings, maps and photos may help determine inclination and orientation, an accurate estimation of shade effects will typically require a site visit. A solar installation contractor will use a standard estimation method to establish the electrical rating of the PV array in kilowatts peak (kWp), determine the postcode region, determine the array pitch and orientation, and look up kWh/kWp from a location-specific table. Solar panel installer training is available for people involved in the Solar PV installation chain who may not necessarily carry out the installation, in addition to existing electricians and solar panel providers who would like to offer Solar PV installation to new and existing customers. Solar Instruments There are two groups of instruments used by solar installers: irradiance meters and solar installation testers. Irradiance meters allow an engineer to obtain a reading from solar equipment such as solar panels in order to calculate exactly how much solar power they can generate from a particular location. Solar irradiance is the amount of solar energy arriving at a specific area. It is important to measure solar irradiance because factors such as the earth’s tilt, cloud cover and the angle of the sun in the sky all play a part. Solar power essentially depends on the earth’s current location and the state of the atmosphere around it. Solar irradiance meters essentially measure ambient light and provide readings at different times of the day of the amount of sunlight provided at particular times. Shade from trees, overhead power cables and similar obstructions all affect irradiance performance. Irradiance meters need to be placed as close as possible to the surface where the proposed panels are to be mounted. The highest reading obtained will determine optimum placement for the maximum economic benefit from installing the panels. In the case of solar installation testers, the tools required for fitting and testing PV solar panels are similar to those used by most electricians, such as clamp meters and multimeters, but with PV-specific measurements on PV peak power and current, depending on the type of inverter installed. For example, maximum power point tracking (MPPT) grid-connected inverters work by linking low voltage PV panels of typically 24-48V in series in order to raise voltage to the 230V mains requirement. The PV installation contractor will use solar installation tester to measure the output to ensure the panels are functioning correctly. Conclusion Solar PV installation is not rocket science but necessitates adequate training and instrumentation in order to fulfil the conditions necessary for maximum power efficiency to ensure the best energy savings from PV installations.

Keeping Abreast of the wiring regulations 3rd amendment

Electricians now have less than six months to revise the new regulations and make any necessary adjustments to their methods and working practices. According to the IET, there are clearly a lot of questions around the changes, particularly concerning consumer units. In this update, a number of potentially life-saving changes have been proposed, which include changes to consumer unit enclosures to come into effect January 2016 and wiring in escape routes. These suggested improvements have come through from London Fire Brigade (LFB), who has been consulting with Electrical Safety First and the manufacturers’ association (BEAMA). The reason that LFB has driven for these changes is because of the amount of fires that a consumer unit is identified as the source of ignition – currently around five a week. Over recent years LFB has recognised a large increase in the number of consumer unit related fires. Clearly there is a dangerous trend occurring here. LFB thinks this increase to be mainly due to consumer units with components which are subject to product recall, manufacturers mainly using moulded plastics for consumer unit casings and cables not being securely tightened when installation or maintenance is carried out on the installation. The secondary concern that LFB has raised is that the consumer units are quite often installed in a cupboard under the stairs. This raises concerns as the stairway is obviously an essential pathway for an emergency escape in a fire scenario and if the fire was to start from the consumer unit it would not take a long time for the escape route to become engulfed by fire and impossible to use. LFB has also contributed with the introduction of new requirements for cabling installed above ceilings that are liable to collapse in a fire (suspended ceilings for example). Other changes include changes to earth fault loop impedances for all protective devices, the risk assessment approach for the omission of RCDs in non-domestic situations, updated EIC and electrical installation condition report (EICR) forms for electrical contractors, and changes to definitions throughout the Wiring Regulations. As in previous revisions to the Wiring Regulations, Amendment 3 is backed by an updated On-Site Guide, which gets down to the specific works on small scale electrical installations, as well as Guidance Notes covering assorted issues like isolation of outdoor lighting, circuit-breakers used as switches, changes to earth fault loop impedances for all protective devices, earth electrode testing, heating equipment, and protection against electric shock and overcurrent. Special Locations Guidance Note 7 Special Locations is for anyone working with electrical installations in specific locations where guidance may vary such as bathrooms, outdoors and medical locations. Amendment 3 changes include cables in bathrooms, outdoor lighting, extra low voltage (ELV) lighting, and mobile and transportable units. Some of the potential changes to the current 17th Edition Regulations are expected in Part 2 Definitions. This section could be expanded and modified with some of the terminology changing to avoid confusion and promote further clarity. As for specific chapters, Chapter 52 Selection and Erection of the Wiring Cables: Cables concealed in a wall or partition, could be rewritten and all references to the phrase ‘under the supervision of skilled and instructed persons’ may be removed. Section 557 Auxiliary Circuits is a proposed new addition to the regulations and will cover things like auxiliary circuits for low voltage electrical installations. These types of circuits are for the transmission of signals intended for the detection, supervision or control of the functional status of a main circuit. Section 717 Mobile and Transportable Units – This covers units which are self propelled, towed or transportable containers or cabins. Risk reduction requirements include automatic disconnection by RCD, accessible conductive parts to be connected through equipotential bonding to the main earth terminal within the unit, and the type of supply, voltage rating, number of phases, on board earthing and maximum power required. Section 559, 714 and 715: Luminaires and Lighting Installations – Changes are proposed to bring this section together with the latest IEC and CENELEC standards. Section 715 Extra-low Voltage Lighting – This refers to installations supplied from sources with maximum rated voltage of 50V AC or 120V DC. With respect to Section 714 Outdoor Lighting Installations, only minor changes are proposed in this section including things like requiring individual circuits to be isolated. As for Chapter 41 Protection against Electric Shock, it is proposed that any reference to ‘ordinary persons’ is removed and protection for socket outlets up to 20A for all installations is required. However, those with RCD protection for specific labelled socket outlets or where a risk assessment has decided that RCD protection is not necessary are exempt. Cmin factor It is proposed that the maximum earth fault loop impedance is revised to account of the Cmin factor – the minimum voltage factor to take account of voltage variations depending on time and place, changing of transformer taps and other considerations. Notes on the tables will be changed to reflect maximum permitted operating temperature. Chapter 42 Protection against Thermal Effects – Regulation 421.1200 requires switchgear assemblies including consumer units to have their enclosure manufactured from non combustible material to help protect against fire. A few changes are proposed to the electrical installation condition report and notes. It proposes changes to the certification of new work – the schedule of inspections for new work to be replaced by examples of items that require inspection during initial verification. PASS runs a number of one day 3rd Amendment seminars aimed at raising awareness of these changes among electricians and helping to interpret its content throughout the UK.

Electrical Installation Condition Report – what’s next for homeowners?

Your insurance company wants you to have a report carried out on your electrical installation. You contact three companies to get competitive quotes. You accept and the work is carried out, report submitted and invoice paid. Six months later you get a knock on the door by the HSE and now you find that you are being prosecuted. What went wrong? Your insurance company is happy, you’ve have had your electrical report carried out. So why are you being handed improvement notices? The reason for this is that with many people having these services carried out, once the report has been completed they simply file it away at the bottom of a draw and never act upon the recommendations inside. The report could have a thousand observations on it but you could probably put money on them never being touched, the faults highlighted staying put for the next time the building is tested and the report never seeing the light of day. I say time and time again, “A report does not make your complaint, it is what you do with it afterwards that matters the most.” With all reporting services they are the first step to ensuring a safe working environment, not the final stage. Once the inspection has been completed the real work begins. It is good at this stage of the article to highlight what an electrical condition report is not. It is not a certificate. It never has been, it does not certify that the installation is safe for continued use; it does not absolve you of all sin and is not the answer to all your prayers. I have had countless people over the years ask that when the corrective works have been completed after the initial condition report was carried out, they would like me to re issue a satisfactory certificate? My answer is no, it is not a certificate. It is a report. As mentioned above, the electrical installation condition report is the first step to a continued program of maintenance that ensures safety, not the final stage, but the first step. While this is done by periodically testing and inspecting the property, it is the production of the report, its contents and subsequent actions which are important. Condition reporting is a two stage process You have your report carried out, this will require a test engineer to inspect and test a percentage of your installation in order to provide you with a report including any recommendations found at the time of test. All corrective works that are carried out are supported with the relevant certificate or work sheets. With the initial report and the supplementary minor works documentation this is more than sufficient to highlight to the HSE that you are fulfilling your duty in ensuring a safe working environment. Failing to take action While many get bogged down in testing specifications, testing percentages, rolling programs and so on, just remember that the percentage of the installation inspected and tested is not as important as the report itself. Guidance note three of the Wiring Regulations 3.8.4 states “that the inspector must be familiar with setting sample sizes as carrying out 100% inspection and testing in installations is unrealistic, uneconomical and unachievable”. Failure to address these issues will result in prosecution as was the case with Keighley Lighting, a West Yorkshire firm prosecuted over unacceptable working conditions by the HSE!. In this instance, the HSE found during their inspection an electrical report that had been left to one side for a considerable amount of time and on investigation it was determined that there were over 70 items highlighted which had not been dealt with.Keylighting Ltd, of North Brook Works, Alincote Street, Keighley, was prosecuted by HSE for breaching the Health and Safety at Work Act 1974 between 25 May 2010 and 25 January 2011. The company pleaded guilty and was fined £8,000 with £20,000 to pay in costs This and other examples of work place negligence go a long way in helping raise awareness and helping create safer working environments for all Section 2(1) of the Health and Safety at Work Act 1974 states: ‘It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees’. And while electrical inspection and testing is not a statutory requirement, the statement above is and is quite frequently enforced So how can you protect yourself? It is pretty simple, whoever you have dealing with your inspection. Ask them for two things a) A quotation to correct the works highlighted. b) A proposed program to highlight when and how the work is to be done. This will show that you have been inspected and there is evidence to prove that you are serious in keeping your work place safe. There has been a great deal of conversation regarding having different companies carry out corrective works and testing. In short that is a decision for you to take; while it be advantageous for a company to maintain an element of commercial impartiality, it is not vital. As long as the work carried out is certified at the end that should be enough. We have come across testing companies who insist that should work be carried out by another company, you must have the initial testers return to certify their work. Let me assure you that this is completely false. No matter how big or small the works are, the contractor is required to certify their work with the production of the appropriate certification. Claiming that their report will be void should anyone else touch your site is just plain incorrect and should be dismissed outright. It can be however, more effective to have the same testing company carry out the remedial works as they will have a better understanding of the environment, however if you have your own spark then get them to do it. Why pay more? Prior to the introduction of the new electrical installation condition reports, many a client would dismiss reports recommendations as being silly and trivial in their findings, and to be honest they were. One of the main problems encountered with periodic inspections were that they became blank cheques for contractors to drum up additional work in the form of remedial actions. The new reporting format was designed to eradicate that and bring a sense of trust and honesty back into the market. Multiple circuits protected by one device, untraced circuits, screw missing, was to be removed from the condition reports as while they may not comply with regulations, they do not in many cases impair the integrity and safety of the installation. Having a good understanding of both the client’s requirements and that of the wiring regulations is essential in order to approach an installation in a much more measured fashion. We may be slowly coming out of this recession, however the main aim of any credible compliance company should be to help their clients stay as safe and as compliant as they can, without spending a penny more than they necessarily have to. I think this and dedication to service delivery should be the fundamental principles of any good company wishing to build trust and credibility within the workplace environment. The important thing is, get your property checked properly and more than that, act upon the recommendation made after the testers leave and go home. By following this simple rule you should always be ready should the HSE come knocking.

Are you leveraging the benefits of LED lighting?

Talks of phasing out class D halogen light bulbs in the EU have been ongoing for some time. But earlier this year, member states voted to postpone the ban by two years, from 2016 to 2018. Why? Because they believe alternative LED lighting is not ready to replace them. Obviously, as electricians, there is a limit to the help we can offer the lighting industry. And we must trust that they know exactly how long it will take to develop all of their technologies for wide-scale distribution. However, those of us that are ‘pro LED’ will be very aware that there are some fantastic LED bulbs already available on the market, for a price and quality that some people thought we wouldn’t see for some time. So, whilst we wait for the introduction of the ban, we should be highlighting the benefits of these clever, energy efficient lighting solutions. Then, when inefficient halogens are finally phased out, few people will even care. So, what benefits can you push to your customers? Talk about energy savings in pounds and pence A reduced carbon footprint is something that many people would like to achieve. But for a customer to save up to 80% on their energy bills is the icing on the cake. So pass this message on. The savings add up too. Energy efficiency campaign group Coolproducts has reportedly predicted that the halogen ban delay will mean a loss of €6.6bn (£4.8bn) energy savings for consumers. But we don’t have to miss out on a share of these savings, just because the ban is yet to be enforced! The long-life maintenance-free guarantees that come with LEDs also protect customers’ investment for years to come. Show like-for-like light quality There is a common misconception that due to the energy efficiency of LEDs, the quality of lighting is not comparable. So why not provide your customers with the two bulb options and let them see for themselves? There is no ‘warm up’ period as some people expect – only instant light. And they don’t cast a harsh, bright light as others predict. They can even improve safety In commercial settings, where the quality of light is important, LEDs can even uphold health and safety standards. This light quality is maintained for the entire lifespan of the bulb which means office workers won’t start to strain their eyes and warehouses won’t start to become poorly and dangerously lit. Keeping staff safe is a priority for many businesses, so mention this message too! In truth, the list of LED benefits goes on, so if you haven’t yet embraced this form of lighting in your product range, do your research and encourage customers to make the switch. Why wait until the ban is upon us? We all need to ‘do our bit’ to protect the environment, so energy efficient technologies cannot be ignored for much longer. But LEDs don’t just safeguard the world in which we live – they save money too!

Lets talk about your electrical project today.

Get in touch