Electrical Information

Batiment Basse Consumption

As part of it's commitment to lowering carbon emissions the French government has proposed a target that all new houses should have an energy consumption level of only 50 kWh of energy per m² per year. A house built to this standard is called a Batiment Basse Consumption or BBC, but there are very few yet that have achieved that level and of course there is a cost to realise that level. At the moment there is a great deal of discussion and research on whether the BBC is economically viable in the volume house building sector. The studies are looking at two systems of ventilation, three types of fuel (electricity, gas and wood) for five types of heating and six methods for producing hot water in the eight climatic zones of France. In total, 25000 simulations have been run. These are all high ideals and will lead to significant cuts in domestic energy use in the future, but what of here and now? I find quite often that there unnecessarily high levels of energy consumption from houses, which are poorly insulated.

As a heating installer, I am required to calculate the energy losses from a building in order to provide enough means of heat for the occupants to be comfortable. In doing so I run a simulation which shows the projected costs of running the heating system for a year. By changing the parameters for insulation there can be a staggering difference. For example, let us take an average sized house of 120m² with ceilings at 2.5m. At 1970 levels of insulation, which is the case of a house with uninsulated walls, single glazing and minimal loft insulation, the projected annual cost of heating by electric would be 2373€, yet with levels of insulation to the regulations of 2005, this would be halved to 1278€. Using an air source heat pump these figures would be 850€ and 429€ respectively. If you want to know more about the heat losses from your home commission a thermal image picture or a full thermal study.

Plan Ahead

Dispite the cold over the winter period we have had a number of requests from people building their own houses or renovating an existing property, who have said that they are ready for the electrics and plumbing now. Apart from the short notice to get a wiring and heating plan worked out, a quote prepared, accepted and signed, the scheduling of staff and the ordering of materials, it means that we have missed an opportunity to get pipework and cable runs tucked away. This is particularly true in the case of new builds, where the concrete slab is an ideal place to pass the cables. If the electricians are able to lay the gaines and bring them up in the appropriate position before the concrete is poured, it makes for a tidy and time-saving installation.

Once the concrete is down, it’s too late, as the wiring regulations do not permit the passage of cables in the cement screed because the cables would be vulnerable to being damaged by someone unknowingly drilling into them. Going back to the log fires and sunshine, with which I started the article, this is such a good time to think of solar water heating. So often, people start to consider solar water heating during the hotter months when there is a lot of sunshine and it seems like a good idea to use this renewable resource to heat the household’s domestic hot water, but for the manufacturers and installers it’s easier to sell the systems at that time of year. However, in wintertime, when demand is reduced, the manufacturers often offer the installers good discounts on their systems, which we are able to pass on to the customer. So while you are sitting in that snug armchair in front of the fire, it makes sense to get out the planning pad and consider your requirements for your building program next year or whether you think it is worth benefiting from the free resource of the sun’s radiation to heat your water.

Don’t forget, the French government is offering interest-free loans for energy saving improvements on existing houses and there is tax credit available for having certain types of renewable energy systems installed.

Harnessing the benefits of the sunshine

One way to do so is through the use of solar water heating systems. These systems use collectors, often mounted on the roof, which absorb solar radiation and use it to heat water for domestic use in the home. There are three types of collectors: the most basic form has the water circulating through a heat absorber usually coloured black and open to the air, the second method is with a block of double skinned tubes, one of which contains a heat transfer fluid, the third and most common has copper tubing in a case insulated on all sides apart from the face, which is glazed. The collectors are connected to insulated pipework of either stainless steel or copper and on the other end of which is the coil. This is the primary circuit and it contains the heat transfer fluid. The fluid is a water and antifreeze mixture having the capability to withstand the lowest expected winter temperatures for the area. The coil is situated in the reservoir for the domestic water, we usually install 300 litre cylinders for the average sized home, but they are available from 200 to 500 litres. The water in the cylinder is known as the secondary circuit and this is what is piped around the home to provide the domestic hot water.

The reservoir sometimes has an additional primary coil and this may be connected to either a conventional boiler, a wood burning stove with back boiler or a heat pump. The purpose of the additional coil is to provide a back up facility in the event of there being insufficient solar radiation to heat the domestic water. As an alternative to using a second coil, the back up may be provided by an electrical element inserted into the cylinder. This method is particular suited to an installation where there is not an existing boiler, for example when we are replacing an electric immersion heater. The other components of the system are a motorised pump to circulate the heat transfer fluid, an expansion vessel to absorb the increased system pressure as the water temperature increases, a pressure relief valve to safely discharge excess pressure and a mixing valve to ensure the domestic hot water leaving the cylinder is not hotter than 60°C.

Last year a law was introduced governing the transportation, handling and use of refrigerant fluids to aid the efforts of the French government to meet its obligations under the various international protocols. Since the 4th of July 2009 no-one can buy refrigerant fluids unless they hold a certificate proving their competence and ability. However, it is estimated that only between 10 and 20 % of operators have obtained their authority before the deadline. As might have been anticipated with any such change, many companies left it to the last minute to apply and the number of applications still pending means that some legitimate operators are unable to work legally on any activity concerning heat pumps and air conditioning equipment.

The ministry have therefore decided to grant a four month tolerance in some cases for those firms who have submitted their application providing they can justify their case. This applies to around another 40% of operators, so its seems as though about half of the operators in France have decided to stop working in the activity or are going to continue illegally. The professionals who have chosen not to apply may have done so because of the stringent tests or the costs of having to have the minimum level of specialist equipment, but those who did not make the step will thus find it impossible to lawfully buy fluid and to handle refrigerants.

The penalties for contravention are heavy. For each purchase by an operator or sale by a distributor the fine is 450 euros. For illegally working with refrigerant, the first offence is 1500 euros and 3000 euros for each subsequent offence. The most severe infractions, such as causing a leak of CFCs carries a 2 year prison sentence and a 75000 euro fine. The next few months will show just how determined and strict the french authorities are going to be on this subject, but with President Sarkozy's drive to show France as a leading player in environmental matters, it would seem likely that offenders will be brought to book.

I had a question from someone who was concerned that 12kW would be an insufficient amount of electricity to run his house properly. He has a hob (5.8kW), an oven (2.6 kW), a 3kW water heater, three electric heaters of 2kW each, a kettle (2kW) plus washing machine, dishwasher, fridge, freezer, TV and various lights and other appliances. He calculated that he would need at least 20kW for this houshold to avoid tripping off and asked if there was a system to manage the appliances. There is a device that manages electrical consumption and prioritises the circuits to prevent the system exceeding the contracted supply.

The heating system is treated as a lower priority than the sockets and lighting and it works thus. Imagine a cold day when the heating is working and the occupants have on the lights, TV, washing machine and lunch is being prepared. At any point when the consumption is about to exceed 12kW, the supply to the heaters is temporarily reduced for a brief period until for example, the washing machine finishes its heat cycle or an element on the hob is switched off.

During the reduced supply to the heating there should not be a noticeable temperature drop, as the supply cascades across the heating circuits rather than turning all of them off at once. The device works using the pilot wire, which is fitted to nearly all heaters on the French market. If the heating circuits do not have the pilot wire as in some older installations, then the system should still be controllable, but using a slightly different version of the device. Free-standing portable appliances plugged in to sockets cannot be managed.

The credit d’impot, or tax credit, was created in 2005 to encourage long-term development, energy economy and reduce emissions contributing to the ‘greenhouse effect’. The types of equipment that are covered include airothermic/geothermic heat pumps, reversible air-conditioning systems, some insulating material and certain items for the control and regulation of heating systems. The last group could be part of an electrical heating system, providing the devices regulate the heating from a central point and manage the energy consumed by the heating appliances.

These items attract a tax credit of 25% or 40% if they are installed in a house constructed before 1 January 1977. By contrast, the rate of tax credit for heat pumps installed since 1 January 2006 is 50%. However, to be eligible the heat pump must have a coefficient of performance of equal to or greater than 3.3. This is its efficiency rating and means that for 1kW of energy consumed there must be 3.3 kW of energy produced. The tax credit (in the form of a cheque) is available for installations at a principle residence carried out by a recognised firm/installer, so it is not available on DIY installations, and is only applicable on the price for the equipment. The maximum amount which can be claimed against is 8000 € for an individual or 16000 € for a couple.

Three Phase Supply

Many houses around here have 3 phase electrical supplies whilst in Britain this was usually only supplied for industrial uses. The reason is largely linked to the size of the country and the distance between settlements. Electricity is generated in three phases and supplied down to local transformers in that form. The use of all three of these phases in a property means that the load is spread over three cables and therefore these can have a smaller cross-sectional area as they carry less current and are therefore less expensive. The downside of a three-phase supply is that if too many domestic appliances are used on the same phase at the same time the supply may trip off because the current has exceeded the tariff at the meter. If this were a persistent problem, the solution would be to ask a qualified electrician to check that that the system was balanced out correctly. However, on an old installation, which had evolved in an unbalanced way over the years, it might be necessary to consider having your supply changed to single phase. This should be straightforward but again, consult a qualified electrician, who can advise you accordingly and make the arrangements with EDF.

Warning: Dangerous Electrical Installations

The numbers are frightening: 22.5% of French residences present an electrical risk. In fact 7.5% are equipped with electrical installations that are qualified as “very dangerous” in a study by the organisation, Promotelec. Each year 300 000 installations are added to the 7 millions needing a partial or total renovation. The anomalies concern essentially the circuits in the bathrooms, the earthing arrangements, the consumer units and the existence of proscribed components. As well as these disquieting facts, there are some that are even more dramatic: defective electrical installations kill 100 people and cause 80 000 fires in France every year. (Source: Thierry Devige-Stewart, Le Moniteur, 03/11/2006)

If you have doubts about the safety of the electrical system in your home you could commission Promotelec to inspect your property or contact us to arrange for an inspection to be carried out.

French domestic wiring standards are very strict and for a new electricity supply, you need to have an attestation de conformité (a certificate of compliance) from Consuel (link on links page), which is issued only after an inspection, before you can get a connection from EDF. If Consuel require additional work to be done you will have to pay for another visit before the work will be passed.

The likelihood of being affected by lightning can be determined by the number of lightning strikes per square kilometre per year, the result is the Ng value or Ground Flash Density. For the Haute Vienne, the Ng value is 2,3; the Charente is 2,1 and the Dordogne is 2,7. Where the Ng value is greater than 2,5, it is obligatory to install a lightning protection system. It is also strongly advised where the property is either in an isolated position, closer than 50m to trees or buildings higher than 20m or supplied by overhead power lines. The protection of telephone lines is as important as the electrical system as these are also vulnerable to the effects of lightning strikes.

Did you know?

According to EDF and Promotelec, an organization charged with promoting the safety of electrical installations, 7.3 million homes in France dating from before 1974 do not meet the minimum standards for electrical safety. The director of Promotelec has said that there are two levels of concern.

The first level concerns stripped insulation, bare cables and damaged switches and sockets.

The second, which is less obvious and more difficult to define, concerns the risk of electrical installations more than a quarter of a century old when the non-visible parts of an electric circuit can be potentially dangerous.

France produces more electricity than it uses and exports to other countries with over 80% of production being from Nuclear reactors and over 8% from renewable sources.

A bolt of lightning can reach temperatures approaching 28,000 Kelvin (50,000 degrees Fahrenheit) in a split second. This is about five times hotter than the surface of the sun.