When considering fitting recessed downlights, there are certain factors to consider that relate to the passage of fire, sound and heat loss.
FUSE Services will always consider these things for you and will make sure your property is safe and complies with BS7671 (electrical regulations), Document B (Fire safety), Document P (electrical Regulations), Part E (transmission of sound).
The electrical contractors responsibilities in these areas are increasing all the time, but unfortunately, less “scrupulous” contractors often fit “cheap” contractors units offering no protection whatsoever and able to offer a “cheap” service. Unfortunately, all to often we are called in, sometimes after the fire service has attended, after wiring has burned out, insulation in lofts has begun to burn, and problems have started with fittings melting etc.
The problem is this. Ceilings are designed with a 30, 60 or 90 minute fire rating, to give enough time for persons to be rescued by the fire service if they are trapped in upper levels of a building. Once you cut a hole in a ceiling, you immediately destroy the ceilings ability to hold back a fire which can now spread much faster setting fire to the wooden joists and floorboards above.
Another problem is lofts. Currently there are no requirements to have fire rated units in a ceiling with a loft above, as there is no dwelling above, but considering how much timber is in the average loft, it would be crazy not to fit a fire rated unit.
We ONLY fit fire rated units that have an intumescent seal in them, which in the event of a fire will expand many times over, completely sealing the hole up and giving a 90 minute protection. If you remove a bulb in a downlight and can see straight through to the floor above, then you don’t have a fire rated downlight. The regulations have been in force since at least 1987, so they are not new – just ignored for “competitiveness”!
The other problem is maintaining insulation in lofts over downlights. Again we often see poor practices where insulation completely surrounds a downlight. This is very dangerous as heat can build up and insulation starts to melt and burn. A solution is to keep the insulation well away, but this then compromises the properties insulation and heat escapes.
We always recommend a loft cap or loft brace which protects the light unit, and insulation may then be placed safely over the whole assembly, maintaining the insulation properties in the loft (or other floors too).
A fire hood can be used to prevent fire spreading through floors, but must NOT be used in a loft with insulation placed over it. This is the wrong use of this device, and again we unfortunately see this practice all the time!
Bulbs, namely the MR16 (Low voltage) with Dichroic reflectors, commonly reflect visible light forward whilst allowing the invisible infra-red light (RADIATED HEAT) to pass out of the rear of the fixture, resulting in a beam of light that is “cooler”.
The integrated dichroic reflector, was originally designed for use in slide projectors to avoid melting the slides and photographic film, but now widely used for interior home and commercial lighting with a decorative purple coloured light coming from the rear.
Also if the luminaire is a fire rated unit with intumescent seals, they are likely to activate the seals prematurely and cause the lamps components to melt and drip onto the surface below, and harden / damage the seals preventing them operating when required.
For these applications non-cool beam (ALU or Silver back) lamps must be used.
NEVER EVER use a dichroic bulb for a downlight.
They can be easily identified if you hold them up to the light and look through the rear of the bulb. A dichroic bulb will have a purple or pearly colour, whilst an aluminium reflector bulb will look dark and silver as it won’t pass any light (or heat) through.
Unfortunately, both types are sold side by side, are totally interchangeable and are still called MR16 and GU10, but are VERY different, dichroic are usually cheaper and more likely to be selected. We have contacted several DIY stores asking why they don’t stock the correct type of lamp, but they declined to answer – ALL of them?
Lamps suitable for use in recessed or enclosed luminaires will have the ALU or aluminium reflector on the packaging and will have a symbol showing red wavy lines (heat) coming from the front of the bulb.
Why on “earth” does my bonding need checking?
Have you decided to have additional electrical socket outlets, new lighting points, a new circuit installed (such as an electric shower) or any alterations to electrical circuits in your home? If so, we as registered electricians are required, prior to starting work, to verify the earthing and protective bonding arrangements in your property are adequate and up to date.
After completion of the electrical installation work no matter how small the job, the work shall be inspected and tested and a certificate issued. Part of this process is to verify that the earthing and bonding conductors are correctly sized, installed and terminated correctly.
Supplementary bonding is often found in bathrooms or any other room containing a bath or shower. This is to reduce the risk of electric shock where people may touch two separate metal parts, such as radiators and water pipes, when a electrical fault occurs in the electrical installation.
In these locations supplementary protective bonding conductors connect together the circuit protective conductors of electrical equipment e.g.
Water pipes and any metal radiators or towel rails.
As illustrated this arrangement was common on installations up to June 30th 2008.
With the introduction of new IEE Wiring Regulations BS7671 (2008), after this date the need for supplementary bonding has been reduced, as all electrical installations in rooms containing a new bath or shower need to have their circuits additionally protected by a Residual Current Device (RCD).
A protective conductor connecting the main earthing terminal of an installation to an earth electrode or other means of earthing.
A protective conductor connecting exposed conducting parts of equipment to the main earthing terminal.
Protective conductor provided for protective equipotential bonding.
A protective device which operates when an earth fault is detected.
The conductive mass of the earth, who’s electric potential at any point is conventionally taken as zero.
Correctly installed earthing and bonding can protect you from the risk of electrocution and fire caused by faulty equipment or appliances.
We can advise you on whether your earthing and bonding installation requires improvements to maintain your safety in the event of an electrical fault occurring.