Monday, 31 January 2011

Lighting – a changing world (technical)

“INCANDESCENT” might well describe the rage of those who prefer traditional light bulbs to their low-energy alternatives. The European Commission formally adopted new regulations that will phase such bulbs out in Europe by 2012. America will do so by 2014. Some countries, such as Australia, Brazil and Switzerland, have got rid of them already. When a voluntary agreement came into force in Britain, people rushed out to buy the last 100-watt light bulbs. Next to go are lower-wattage bulbs.

But what will replace the light bulb? Although obtaining illumination by incandescence (ie, heating something up) goes back to prehistory, it was not until 1879 that Thomas Edison demonstrated a practical example that used a wire filament encased in glass. Modern bulbs, the descendants of that demonstration, are cheap but inefficient, because only about 5% of the energy they use is turned into light and the rest is wasted as heat. A typical bulb also has to be replaced every 1,000 hours or so.
Without changing light fittings, the cheapest direct replacement for an incandescent bulb at the moment is a compact fluorescent light (CFL). These use up to 75% less power and last 10 longer. They object not to the price but to the quality of the light, which has a different spectrum from the one they are used to. CFL bulbs can also be slow to reach maximum illumination. And some people worry that they may be bad for the health. Fluorescent lights use electricity to excite mercury vapour. This produces ultraviolet light that causes a phosphor coating inside the bulb to glow. The lights can flicker, which could set off epileptic fits, and badly made ones might leak ultraviolet radiation, and may thus pose a cancer risk. There are also concerns about the disposal of the toxic mercury.

The most promising alternatives are light-emitting diodes (LEDs). An LED is made from two layers of semiconductor, an “n-type” with an excess of negatively charged electrons, and a positive “p-type” which has an abundance of “holes” where electrons should be but aren’t. When a current is applied across the sandwich, the electrons and holes team up at the junction of the two materials and release energy in the form of light. The colour depends on the properties of the semiconductor, and these can be tuned to produce light that is similar to natural daylight but with virtually no ultraviolet or heat.

Light-emitting diodes have progressed from simple red indicators on electronic products to become torches, streetlights and car headlights. Now the first mains-voltage LEDs designed as direct replacements for incandescent bulbs are on the market. Some, such as the Philips Master LED range, promise energy savings of up to 80% and a working life of 45,000 hours. But they are not cheap in Britain.
Even so, LEDs can still be economical. Only a quarter of lighting is domestic. Businesses and public organisations are more aware of running costs than householders are—and besides the electricity bill they also have to pay people to change bulbs that have failed. For the bulbs to be embraced by households, though, LED costs will need to come down.

Manufacturing efficiencies, as always, will help. But the biggest cost reduction will come from breakthroughs like that recently made by the Centre for Gallium Nitride at Cambridge University, England. Gallium nitride is a semiconductor used to create bright-blue LEDs. These can be made to emit white light by coating the device with a phosphor compound that absorbs part of the blue light and re-emits it as yellow. When combined with the rest of the blue this forms a cool, white light. Most of the white LEDs now on the market are based on gallium nitride.

At present these LEDs are made in machines similar to those used to make silicon chips, by depositing layers of gallium nitride on sapphire-based wafers. Sapphire is robust enough to withstand a process that first heats it to 1,000°C and then cools it to room temperature without causing cracks and other defects. It is, however, quite expensive. What Colin Humphreys and his colleagues at Cambridge have come up with is a reliable way to deposit gallium nitride on much cheaper silicon wafers, which they estimate could cut production costs to a tenth of what they are at the moment.

Because the atomic lattice structure of gallium nitride is better matched to sapphire than it is to silicon, making LEDs on silicon without distortions has proved extremely tricky. The technique used at Cambridge involves depositing additional layers of gallium nitride-based materials, one as a “compression layer” to provide greater resilience and another as an ultra-thin mask that increases the accuracy of fabrication. The important measure of success is the internal quantum efficiency, which shows just how good an LED is at making light. A gallium nitride LED on sapphire has a typical internal quantum efficiency of around 70%. In the past year, Dr Humphreys’s team has improved its silicon-based ones from 15% to 45%.

Friday, 28 January 2011


Electrical and electronic equipment waste is becoming a serious problem in most countries. Electronic and electrical equipment includes appliances that need electricity like kettles, vacuum cleaners, washing machines, mobile phones, television sets, computers, lapstops, video games and others.
These appliances contain dangerous substances such as lead, mercury, cadmium and other heavy metals that are known to cause pollution and health problems in individuals. There are several benefits of recycling that consumers need to be made aware about. Dismantling these electrical and electronic appliances allows the different parts to be reused and controls the buildup of waste. In addition, metals procured during recycling can be utilized in other industries and further reduce the amount of waste.
Both manufacturers and consumers are responsible for recycling electrical and electronic equipments. There are efforts to raise the awareness about the benefits of recycling electronic and electrical equipment by different organizations. Consumers can help by reducing the waste of these appliances and restricting their purchase to only those items they need urgently. They should consider borrowing or renting electrical and electronic equipment they are going to use occasionally.

In addition, consumers should consider sharing or giving away the appliances they no longer need to someone needy, instead of disposing it. They are also advised to buy the most energy efficient appliances and ask about the option of recycling at the time of purchase.

The responsibility lies with the retailers to inform the consumers about the prospect of recycling the electronic and electrical equipment they carry. Many retailers also offer exchange programs where the consumers can exchange their old appliances for the new ones free of charge or drop off their old appliances at designated recycling zones.

If you have an item with a picture of a wheelie bin with a line through it (including the batteries), please do not put it in the bin. These items will end up in ordinary landfill and contaminate the water table. Eventually you and your family will ne consuming lead, mercury, cadmium and other heavy metals.

Save them up and do a trip to the tip

Thursday, 27 January 2011

What responsibilities do landlords have?

Your landlord is required by law to ensure:
  • that the electrical installation in the property is safe when your tenancy begins
  • that the electrical installation is maintained in a safe condition throughout the tenancy, and
  • that any appliance provided is safe and has at least the CE marking (which is the manufacturer’s claim that it meets all the requirements of European law).
In order to meet the requirements your landlord will need to carry out regular basic safety checks to ensure the electrical installation and appliances remain in good working order.
A good landlord should have an electrical inspection carried out by an electrician before a new tenant moves in. If your landlord has done this, a copy of the inspection report (known as a periodic inspection report) should be made available to you and if the appliances have been checked then each electrical appliance in the property should have a PAT (portable appliance test) sticker on the plug showing the date it was tested. If the electrical installation and appliances in your accommodation have not been tested, you can ask your landlord to get an inspection done, although they are under no obligation to do so unless you live in a house in multiple occupation (see below). If you're really concerned, you can get an inspection carried out yourself.

If you live in a house in multiple occupation then your landlord has to have the electrical installation checked every five years and a periodic inspection report showing the property continues to be electrically safe must be available.

Wednesday, 26 January 2011

Changing your energy supplier

Changing your energy supplier may be a way of saving on your energy bill, and becoming more energy efficient. There are a number of different comparison sites you can use to see if you could save money on your gas or electricity bill.

Tuesday, 25 January 2011

What responsibilities do I have if I rent my home?

If you rent your home, you should:
·        watch out for danger signs when using appliances:
·              frayed, cut or damaged leads.
·              Cracked or damaged cases on plugs or appliances.
·              Burn marks on plugs, leads or appliances.
·              Blowing fuses.
·              Loose cord grips in plugs or appliances.
  • ensure all electrical appliances are used responsibly and in accordance with manufacturer’s instructions.
  • do not attempt to extend, repair or replace damaged or worn-out parts of the electrical installation yourself.
  • report any problems with the electrical installation or appliances to your landlord straight away.
  • allow access to the property if your landlord and/or an electrician need to visit to carry out an inspection of the electrical installation or fix any reported problem. Your landlord should give you 24 hours notice before coming round.
The safety of appliances you bring into your accommodation is your responsibility. If you are in any doubt as to the safety of an appliance, get it tested or replaced.

Monday, 24 January 2011

what is Economy 7

Economy 7 is a way of paying different rates on your electricity depending on whether you use certain appliances at night or during the day. You can get a special meter fitted (if you don’t already have one), that will measure your electricity use during peak times, and off-peak.
Economy 7 is best suited for people who use electric storage heaters and have hot water tanks in their homes, but it’s not necessarily right for everyone. Generally if you use more than 40 per cent of your electricity at night, it may be worth doing. However, some Economy 7 schemes charge a higher rate than normal for any electricity used during the daytime, so this could make it more expensive than having a standard meter.

Friday, 21 January 2011

Electrical - What are my responsibilities if I own my home?

If you own your home, it is recommended that you:
  • arrange for an electrical inspection (known as a periodic inspection report) to be carried out every ten years.
  • don’t create possible dangers by overloading sockets, and never ignore warning signs like burning smells, sounds of arcing (buzzing or crackling), fuses blowing or circuit-breakers tripping.
  • make sure all electrical equipment in your home is maintained and used properly (in accordance to the manufacturer’s instructions).
You should also ensure all repair and installation work is safe and meets the building regulations. Always use an electrician registered with one of the Government-approved schemes. Registered electricians will work to the UK national standard BS 7671 (requirements for electrical installations), and will issue you with a safety certificate to confirm that their work has been designed, built, inspected and tested in line with that standard. They will also arrange for you to receive a certificate that confirms the work meets the building regulations. The five Government-approved schemes are:

Thursday, 20 January 2011

Services we provide (not comprehensive)

D A Woolgar – Electricians


  • Same Day Electrician
  • NICEIC Approved Contractor
  • NICEIC Domestic Installer
  • Part P Registered
  • Period Testing & Inspecting
  • Rewires, Fuse boards, Showers
  • Lighting, Extra Sockets & More
  • Landlord Certificates

Any questions? Contact us

D A Woolgar - Always Reliable-Always Competitive

Wednesday, 19 January 2011

Electrical Safety

What are the dangers?
The main dangers are:
  • contact with live parts at 230 volts which can cause shock or burns and, in severe cases, death
  • Faults in appliances and installations, which can cause fires.

What are the danger signs?
  • Damaged plugs, sockets and flexible cables can cause electric shocks, burns and fires. Follow these simple rules to avoid problems.
  • Check plugs and sockets for burn marks, sounds of arcing (buzzing or crackling), fuses blowing, circuit breakers tripping or if they feel hot.
  • Remove plugs from sockets carefully. Pulling out a plug by the cable puts a strain on it, and could damage the contact between the plug and socket. This could result in: overheating, wires becoming loose, or an electric shock (if the earth wire is disconnected).
  • Use plugs with the British Standard safety mark – they have live and neutral pins with insulating sleeves that allow you to put them in and pull them out of sockets safely. (Nowadays, electrical equipment comes fitted with a plug.)
  • Look to see that the shutter mechanism in the sockets closes when removing the plug.
  • Always replace damaged cables immediately. Touching live wires may give you an electrical shock or you could even die.

If you are concerned about any part of the electrical installation or appliances in your home, speak to your property owner or call us immediately.

How can I reduce the risks?
There are many things you can do to minimise risks of electrical shocks or fires in your home. For example:
  • have your electrics checked regularly (at least every 10 years)
  • use an Residual Current Device when using electrical equipment outdoors
  • use a registered electrician to carry out electrical work in your home
  • regularly check the condition of plugs, cables and extension leads
  • be careful when using hand-held electrical appliances and ensure that they are switched off and unplugged when you have finished using them
  • check that any adaptor used complies with British Standards and is adequately rated for the connected load
  • have your electric blanket tested every three years (as recommended by Trading Standards Institute)
  • have smoke alarms fitted and ensure that they are all in working order
  • Make sure you can access the fuse box and meter easily. Keep a torch nearby, so you can see what you're doing if the lights go out
  • Plan what to do in case of fire, be aware of all escape routes and make that exit routes are always kept clear.
  • Bring mains powered portable appliances into the bathroom.
  • Overload adaptors, particularly with high current appliances such as kettles, irons and heaters.
  • Use adaptors plugged into other adaptors.
  • Trail cables from electrical appliances (including extension cables) underneath carpets or rugs.
  • Use any electrical equipment or switches with wet hands.
  • Wrap flexible cables around any equipment when it is still warm.
  • Clean an appliance such as a kettle whilst it is still plugged in.
  • Retrieve toast stuck in a toaster whilst it is plugged in, and especially not with a metal knife – there are often live parts inside!
  • Fill a kettle or steam iron whilst it is plugged in.
  • Exceed the recommended bulb wattage for light fittings.

Stay safe

If you need us or have, any questions do not hesitate to contact us

Tuesday, 18 January 2011

LED’s (technical) issues

LED is a diode characteristics of the LED, it can only power one direction. LED light output is usually proportional to the current through the LED, but the white LED will appear in the high current saturation, a significant reduction in luminous efficiency, or even failure, so LED using current rating can not exceed its specifications. In addition, LED light output with temperature is inversely proportional to, so should minimize the use of well-designed power supply heating and cooling system.

LED are driven by DC current, so power and the LED in the city will need an adapter between the LED drive power. Its function is to convert into a suitable AC power LED's current. According to the electricity grid rules and LED drive feature requirements, selection and design of LED drive power to take into account the following:

1. High reliability

Especially as the drive power
LED street
lamps, installed in the high altitude, convenient maintenance and repair cost is also large.

2. High efficiency

LED energy-saving products, driving higher power efficiency. Installed in the fixture for the power structure, is particularly important. Because the LED luminous efficiency with LED temperature decreased, so the LED's heat is very important. High efficiency power supply, its power loss is small, the heat in the fixture on the small temperature rise will reduce the lamp. LED light on the slow decline favorable.

3. High power factor

Power factor is the power to the load requirements. 70 watts under normal use of electrical appliances, there is no mandatory targets. Although not a single power with a lower electrical power factor has little effect on the power grid, but at night we light lamps, the same load is too concentrated, would produce power more serious pollution. 30 watts to 40 watts for the LED drive power, it is said in the near future, perhaps there would be power factor requirements of certain indicators.

4. Drive

Now prevailing in two ways: one is a constant voltage constant current source for multiple sources, each current source separately to each channel LED power supply. In this way, the combination of flexibility, all the way LED failure does not affect the LED's work, but the cost will be slightly higher. The other is a direct constant current power supply, LED series or parallel operation. It has the advantage of lower cost, but flexibility is poor, but also to resolve a fault LED, LED operation does not affect other issues. These two forms coexist in a period of time. Multi-channel constant current output power supply, cost and performance will be better. Perhaps the main direction of the future.

5. Surge Protection

LED Surge capacity is relatively poor, especially the anti-reverse voltage capability. Enhance this protection is also very important. Some LED lights installed in the outdoors, such as LED lights. Since the start grid load rejection and lightning sensors, a variety of intrusion from the grid system will surge, the surge can cause some damage to the LED. LED drive power should therefore inhibit the surge of the invasion to protect the LED from damage ability.

6. Protection

In addition to the conventional power protection, the best increase in the constant current output LED temperature feedback, to prevent the LED temperature is too high.

7 protection aspects

Lighting and outdoor installation type, the power structure should be waterproof, moisture, shells and Fast.

8, the life of drive power LED lifetime compared with the fit.

9 to comply with safety regulations and electromagnetic compatibility requirements.

Monday, 17 January 2011

Public charge points – Electric Cars

the only practical way for drivers to charge their cars is by using public charge points, of which there are thought to be as many as 500 in the UK.

No one has actually added them up.

Even OLEV, the government office for low emission vehicles, does not know exactly how many there are.

Friday, 14 January 2011

Power cuts

If the residual current device and/or circuit breaker have not been tripped, there may be a power cut in your area. Your local electricity network operator or supplier should be able to tell you if a power cut has occurred and, if so, how long it is likely to last. If there has been a power cut, switch off and unplug any expensive electrical items such as your hi-fi, TV and computer - this will prevent them being damaged when the power returns. If you need to use candles for light, never leave them unattended.
You may be able to claim compensation from your supplier if:
  • the power cut lasts for more than 18 hours, or
  • in one year, you have more than four power cuts of at least three hours each, or
  • you suffer particular hardship as a result of a power cut.
D A Woolgar

Thursday, 13 January 2011

Arc lighting design expo

we found the exhibition quite informative.

looks like the future is LED, LED and more LED, lets hope they can sort out the problems of heat management, drivers not lasting the same time as the arrays, light drop off over the lifetime of the array. over driving the LED arrays and the Power factor issues that will stress the neutral when everyone has this lighting.

re the last issue, the power companies are getting worried about it :(

photos on line - links below

photos link

HQ photos link

any questions call D A Woolgar

Wednesday, 12 January 2011

Energy conservation

SOLID-STATE lighting, the latest idea to brighten up the world while saving the planet, promises illumination for a fraction of the energy used by incandescent or fluorescent bulbs. A win all round, then: lower electricity bills and (since lighting consumes 6.5% of the world’s energy supply) less climate-changing carbon dioxide belching from power stations.
Solid-state lamps, which use souped-up versions of the light-emitting diodes, precedent suggests that this will serve merely to increase the demand for light. The consequence may not be just more light for the same amount of energy, but an actual increase in energy consumption, rather than the decrease hoped for by those promoting new forms of lighting.
The light perceived by the human eye is measured in units called lumen-hours. This is about the amount produced by burning a candle for an hour. In 1700 a typical Briton consumed 580 lumen-hours in the course of a year, from candles, wood and oil. Today, burning electric lights, he uses about 46 megalumen-hours—almost 100,000 times as much. Better technology has stimulated demand, resulting in more energy being purchased for conversion into light.
That, at least, is the conclusion of a study published in the Journal of Physics D: Applied Physics by Jeff Tsao of Sandia National Laboratories in New Mexico and his colleagues. They predict that the introduction of solid-state lighting could increase the consumption of light by a factor of ten within two decades.
To work out what solid-state lighting would do to the use of light by 2030, Dr Tsao and his colleagues made some assumptions about global economic output, the price of energy, the efficiency of the new technology and its cost. Assuming that, by 2030, solid-state lights will be about three times more efficient than fluorescent ones and that the price of electricity stays the same in real terms, the number of megalumen-hours consumed by the average person will, according to their model, rise tenfold, from 20 to 202. The amount of electricity needed to generate that light would more than double. Only if the price of electricity were to triple would the amount of electricity used to generate light start to fall by 2030.
Dr Tsao and his colleagues see no immediate end to this process by which improvements in the supply of light stimulate the desire for more—rather as the construction of that other environmental bĂȘte noire, roads, stimulates the growth of traffic. Even now, the interiors of homes and workplaces are typically lit at only a tenth of the brightness of the outdoors on an overcast day, so there is plenty of room for improvement. And many outdoor areas that people would prefer to be bright at night remain dark because of the expense. If money were no object, some parts of the outdoors might be illuminated at night to be as bright as day.
It is worth remembering that when gas lights replaced candles and oil lamps in the 19th century, some newspapers reported that they were “glaring” and “dazzling white”. In fact, a gas jet of the time gave off about as much light as a 25 watt incandescent bulb does today. To modern eyes, that is well on the dim side. So, for those who truly wish to reduce the amount of energy expended on lighting the answer may not be to ban old-fashioned incandescent bulbs, as is the current trend, but to make them compulsory.
A word to the wise – don’t be fooled, an energy saving lamp will only save you money if you use it wisely. If you leave the lighting on for longer or install more light as it is ‘cheaper to run’ you wont make a saving.

Monday, 10 January 2011

The ARC Show 2011: 12-13 January, Business Design Centre, Islington.

D A Woolgar is off down to the ARC Show 2011in Islington to an architectural, retail and commercial lighting exhibition on Wednesday.

we are endeavouring to catch up on the entire spectrum of lighting disciplines to give you a better service.

We are hoping to gain inspiration from influential designers, keep up to date with the latest industry trends and legislation

Learning each lighting discipline with the latest developments and industry legislations and gain inspiration from a showcase of the very latest and innovative lighting products including LEDs, OLEDs, sustainable lighting, daylighting, control systems and switchings, Fluorescents, CFLs, Halogens, Low voltage lighting, HIDs, IP rated lighting, Cold cathode lighting, Industrial lighting, Specialist lighting and much more.

For all your lighting design need, contact D A Woolgar

Saturday, 8 January 2011

Fit a smoke alarm

Make sure your home is fitted with at least one smoke alarm. Smoke alarms are cheap and easy to install, and can be bought at any DIY or electrical shop for as little as £5. Make sure you buy an alarm that meets British Standards, and remember to test the batteries regularly to check they are still working.

Often – if you are on benefits, your local fire department will fit them for you FOC

All modern alarms have a ‘functional life’, usually 10 years. If you have smoke alarms with no date on them, they are probably due for a change.

Please stay safe in 2011.

For advice, contact the fire brigade or D A Woolgar.

Thursday, 6 January 2011

Resetting the ‘trip switch’ in the consumer unit (fuse box)

D A Woolgar guide to resetting your trip

First, locate your consumer unit (fuse board) and check whether the residual current device (RCD) and/or a circuit breaker have 'tripped' (turned off).

An RCD is a switching device that trips a circuit under certain fault conditions, and disconnects the electricity supply. Circuit breakers are automatic protection devices fitted in the consumer unit, which switch off a circuit if there is a fault. 

If the lights are not working, a lighting circuit breaker may have tripped due to a bulb blowing. You will need to reset the circuit breaker by switching it back on, the lights should now work. If they do not come back on, you will need to contact an electrician.

If it is your sockets that are not working, a circuit breaker and/or the RCD may have tripped due to a faulty appliance being plugged in. You will not be able to reset either of the devices until the faulty item has been unplugged from the circuit. If you are not sure which appliance has caused the problem, unplug all appliances, and reset the circuit breaker and/or RCD by switching it back on. Plug each appliance back in, one by one, until the faulty item (which trips the circuit) is found.

If you cannot reset the circuit breaker and/or RCD even with all the appliances disconnected, call D A Woolgar (central Bedfordshire).

For large appliances that are wired into a circuit such as a cooker or immersion heater, check whether the circuit breaker has tripped and try to reset it. If this does not work, call D A Woolgar (central Bedfordshire).

D A Woolgar

Tuesday, 4 January 2011

Electrical Thermal Imaging

Infrared Thermography is non-contact temperature measurement technique and has the ability to see and measure temperature differences in a non-intrusive manner with the use of an infrared thermal imaging camera. Providing many applications in detecting missing insulation, mechanical and electrical faults before they actually give rise to unplanned and costly breakdowns.

If you think a thermal imaging scan might be something you are interested in please contact us

We use a Flir camera