Glossary

Aico - Manufacturer of Heat and Smoke Alarms 

Air Conditioner - (AC or A/C in North American English, aircon in British and Australian English) is an appliance, system, or mechanism designed to extract heat from an area or provide heat to an area using a refrigeration cycle. The most common uses of modern air conditioners are for comfort cooling and heating in buildings or cooling only in transportation vehicles.

Portable Air Conditioner - Portable air conditioners differ from permanent aircons in that they do not have a heat exchange unit. Hot air is instead expelled from the room via ducting and a vent.

Air Curtain - An air curtain is a downward facing fan, typically mounted above an entrance to a building. It is intended to help keep outside air out and avoid cold draught by mixing in warm air from the air curtain.

Air Treatment - The phrase used to describe any process which changes the make up, temperature or humidity content of an environment's atmosphere, and alludes to such products as desk and pedestal fans, extractor fans, air conditioners, dehumidifiers and heaters. Gil-lec make the distinction between air treatment and heating on www.gil-lec.co.uk in order to facilitate easy navigation.

Airflow - Manufacturer of extractor fans.

Alarm
Carbon Monoxide Alarm - There are different types of CO sensors which, because they work in different ways, have different characteristics. All Ei CO alarms use a new generation proven electrochemical cell type sensor. This sensor type has a low power requirement well suited for use in a battery powered alarm in order to avoid frequent battery replacement. The electrochemical sensor works by catalytic action in direct proportion to the amount of CO present. It has a minimum 5 year life expectancy with good immunity to contaminant gases.
Heat Alarm - Heat alarms are less likely to cause false alarm problems as they are not responsive to any type of smoke or fumes, only heat. Because of the potential for a slower response than smoke alarms, they should only be used in a fire alarm system that also includes smoke alarms, and all of the alarms must be interconnected. The BS 5839: Pt.6: 2004 recommends that heat alarms should be used in kitchens. It goes on to suggest that they may also have a role to play in the main living room but they should not be installed in circulation spaces or areas where fast response to fire is required. These are fixed temperature alarms which incorporate a thermistor sensor. The thermistor is a heat sensitive resistor, when the ambient temperature reaches a pre-set point of 58°C, the resistance is lowered and the alarm will sound. They are designed for use in areas where due to high levels of dust or fumes, a conventional Smoke Alarm is not suitable. They are particularly suited for use in a kitchen
(source of 40% of domestic fires), garages or boiler rooms. BS 5839: Pt:6 recommends the use of fixed temperature heat detectors in preference to ‘rate of rise' types due to the reduced risk of nuisance alarm which can be caused by opening hot oven doors etc.
Smoke Alarm - Smoke Alarms come in two basic types: Ionisation and Optical:
Ionisation Smoke Alarm - Ionisation type sensors are particularly sensitive to the almost invisible smoke produced by fast flaming fires. This makes them more liable to false alarm due to cooking fumes if sited in a hallway close to a kitchen. Ionisation alarms are less vulnerable to false alarms caused by dense tobacco smoke, excessive dust and insect ingress. The BS 5839: Pt.6: 2004 Standard recommends that ionisation alarms should not be used in hallways and landings,where there is a risk of false alarms caused by cooking fumes. Ionisation Smoke Alarms contain a small sealed ionising source which causes a small electrical current to flow through the air in the smoke chamber. Smoke particles entering the chamber reduce the current, this is sensed by the electronics and when a pre-set
threshold level is reached the alarm will sound.
Optical Smoke Alarms -  Optical sensors are more responsive to smouldering fires producing large particle smoke typical of fires involving furniture and bedding. They are more immune to invisible smoke produced by 'burning the toast' and similar cooking fumes. This makes them ideal for siting in hallways close to kitchens where false alarms from ionisation alarms may be a particular problem. The BS 5839: Pt.6: 2004 Standard recommends the use of optical alarms in circulation spaces of a dwelling, such as hallways and landings. Optical alarms are prone to false alarm if exposed to steam and should not be located too close to poorly ventilated bathrooms or shower rooms. Optical Smoke Alarms send a pulsed beam of infra red light through the smoke chamber periodically. If visible smoke is present, it scatters the light on to the photodiode light receiver and this is detected by the electronics causing the alarm to sound. Ei Optical Alarms are individually calibrated to ensure correct operation and to reduce the risk of nuisance alarm.
Radiolink Alarm - It is a totally new concept enabling smoke alarm systems to be interconnected without the need for cabling between the alarms. Instead, a radio signal is used to trigger all the alarms in the system.

Alarm Grading System - Six different grades of fire detection systems are defined and - generally speaking - the greater the fire risk the more comprehensive the system should be. Briefly, the Grades are as follows:
GRADE A - A full system with control and indicating equipment
installed to BS 5839: Part 1
GRADE B - Detectors and sounders using simpler specified
equipment
GRADE C - Detectors and sounders or alarms with central control
GRADE D - Mains powered alarms with an integral stand-by
power supply
GRADE E - Mains powered alarms with no stand-by
power supply
GRADE F - Battery powered alarms

Alternating Current (AC) - an electric current that reverses its direction at regularity occurring intervals. Homes have A.C.

Amplifier - Any device used for boosting, or strengthening an incoming signal.

Amp / Ampere - The ampere, in practice often shortened to amp, (symbol: A) is a unit of electric current, or amount of electric charge per second. The ampere is an SI base unit, and is named after André-Marie Ampère, one of the main discoverers of electromagnetism.

Amendment 3: Changes To Consumer Unit Regulations - To read more about Amendment 3 click here

BABT - British Approvals Board for Telecommunications. Approval mark for telephones etc. for use in the UK.

Backdraught Shutter - Used in conjunstion with extractor fans, backdraught shutters prevent air from outside beeing blown back through the ducting and into the room.

BASEC - British Approvals Services for Cables.

Batten

Batten Holder - Term used to describe a wall or ceiling mounted lampholder. Available in straight or angled and heat resistant versions

Battery

Bayonet Cap - Refers to the part of an electric lamp, or lightbulb, which connects to, or fits into, the lampholder. Also known as BC or 'Push Twist' it has two horizontal pins and is 22mm in diameter

BEAB - British Electrotechnical Approvals Board. Approval body for approving electrical appliances for use in the UK.

BC - Bayonet Cap, also known as 'push twist' has two horizontal pins and is 22mm in diameter
 
Box - In electrical parlance, the term 'box' is used in many different situations: 
Adaptable Box -  Used to house cable connections (usually armoured cable)
Earth Box - A box used to cover the terminal connections of cable to an earth spike
Junction Box - used to connect cables. 
Socket Box - Used to mount wiring accessories suchas switches and sockets.
Flush Box - A type of Socket box used when wiring switches and sockets flush to the wall.
Surface Box - A type of Socket box used when wiring switches and sockets proud of the wall

Breaker - Abbreviation for 'circuit breaker': an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city

Bricklight - A light fitting specifically designed to be recessed in walls. Used as accent lighting in domestic situations and as amenity lighting in commercial environments, bricklights can come with louvred or opalised diffusers

Busbar - A strip of copper or aluminum that conducts electricity within a fuseboard. The size of the busbar is important in determining the maximum amount of current that can be safely carried. Small distribution boards or consumer units may have busbars which have a cross sectional area of as little as 10 mm² but electrical substations may use metal tubes of 50 mm in diameter (1,000 mm²) or more as busbars.

 

Cable - A cable is one, two or more wiresbound together, typically in a common protective jacket or sheath. The individual wires or fibers inside the jacket may be covered or insulated. Combination cables may contain both electrical wires and optical fibers. Electrical wire is usually copper because of its excellent conductivity. Electrical cables may be made more flexible by stranding the wires. In this process, smaller individual wires are twisted or braided together to produce larger wires that are more flexible than solid wires of similar size. Bunching small wires before concentric stranding adds the most flexibility. A thin coat of a specific material (usually tin, but it could be silver, gold and another materials and of course the wire can be unplated - with no coating material) on the individual wires provides lubrication for longest life.
Cable Types
Armoured Also known as Steel Wire Armoured, or SWA, this type of cable is used for outdoor aplications and is usually buried in the ground. This extra tough cable has a steel wire sheathing to affording extra protection.
Double Insulated
Twin and Earth Also known as T&E, this is the standard domestic cable used in the UK. Typical applications include lighting and ringmain circuits and higher load circuits such as cookers and showers. Coming in different sizes, (measured in mm) for thos varying applications, the 'twin and earth' refers to its three cores.
Singles

Cable Clips - Used for holding cables in place, cable clips come in a variety of types, from small round clips, used for holding telephone wire for example, to larger remstraps used for holding armoured cables.

Cable Markers

Cable Safe Plates

Cable Ties - Nylon cords used to tie cables together. Using one way teeth and a stopper the ties may be quickly deployed.

Cap -  Refers to the part of an electric lamp, or lightbulb, which connects to, or fits into, the lampholder. Caps come in many types:
ES - Edison Screw is 27mm in diameter
SES - Small Edison Screw is 14mm in diameter
BC - Bayonet Cap, also known as 'push twist' has two horizontal pins and is 22mm in diameter, SBC - Small Bayonet Cap is 15mm in diameter
GU-10 A type of lamp cap recognisable as a ceramic round edged base with two parallel metal studs. Since a GU-10 cap is only ever used on one type of lamp, the mains halogen spotlight known as a 'Hi-Spot', these terms are now widely used interchangably. GU-10 lamps use aluminium reflectors which send the heat back into the luminair.
GZ-10 A type of lamp cap recognisable as a ceramic square edged base with two parallel metal studs. GZ-10 caps are less common than GU-10s but are easily confused as they look very similar. A GZ10 is differentiated by its square edges (a GU-10 has a round edged base). GZ10 lamps were designed with dichroic reflectros which sned the heat of the lamp away from the luminair.
GY- Two parallel pins seen on halogen lamps and come in various sizes which relate to the distance between the two pins, such as GY6.35, GU-10 and GZ10 are both ceramic based caps with two parallel metal studs.

Capacitor - A capacitor is an electrical device that can store energy in the electric field between a pair of closely spaced conductors (called 'plates'). When current is applied to the capacitor, electric charges of equal magnitude, but opposite polarity, build up on each plate. Capacitors are used in electrical circuits as energy-storage devices. They can also be used to differentiate between high-frequency and low-frequency signals and this makes them useful in electronic filters.

 

Capping - Available in either PVC or Galvanised Metal, capping is used to protect cables when they are intended to be plastered over. Typically available in 3 metre lengths.

C-Bus - Clipsal's range of Intelligent Building Controls.

Circuit Breaker - An automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.

Cleat - The term used to describe the cable clips used for holding armoured cable. Also known as remstraps.

Clipsal - Australian wiring accessories company, best known for its 'Cbus' range of Intelligent Building Controls

Conduit - Piping system used for protection and routing of electrical wiring. Electrical conduit may be made of metal, plastic, fibre, or fired clay. Flexible conduit is available for special purposes.

Connector Strip - Connector Strips provide a convenient means of connecting individual electrical wires. They are usually used to connect wiring among various items of equipment within an enclosure or to make connections among individually enclosed items. Connector Strips are readily available in a wide range of wire sizes and are thus one of the most flexible types of electrical connector available. Cables or wires are first 'stripped' to reveal the copper and screwed into the terminals making a permanent connection.

What is a Consumer Unit?
A consumer unit is the electrical device used to distribute power throughout a domestic dwelling. Acting as a safety device, protecting against injury through electrical shock, a consumer unit houses protection devices which also protect household appliances from overload.

A consumer unit's first function is the organisation of electrical 'circuits', such that the different ways in which we use electricity throughout the home may be safely and more easily managed. A typical domestic installation, for example will have the following circuits: Ring main for power sockets and items like washing machines and TVs, Lighting, smoke alarms, cooker, shower etc.

Drawing different amperages these circuits are recognisable in the consumer unit as 'Mini Circuit Breakers'. An MCB protects its circuit against overload. When for example a bulb blows on the lighting circuit the MCB cuts the power to the that circuit, thus protecting the other lights. No other circuits on the consumer unit have been affected.

Under the latest 17th Edition Regulations, a consumer unit must also protect every circuit from earth leakage. This potentially fatal fault occurs when the electricity coming back in to the consumer unit does not equal the electricity leaving the consumer unit. To prevent the lost electricity causing injury special earth leakage devices cut electricity to the problem circuit.

There are two types of earth leakage device: Residual Current Device (RCD) and Residual Current Breaker with Overload (RCBO). RCDs are used to protect multiple circuits. For example an RCD may protect the ring main and downstairs, upstairs and outdoor lighting circuits. In this instance when there is a fault on the outdoor lighting circuit power to all circuits will be cut by the

Whilst common practices and standards obviously exist every installation is different. Consumer unit come in a variety of types and sizes with a range of differing features and functionality.

Types of consumer unit
Split Load Consumer Units - Typically, a consumer unit with Main Switch and either 1 or 2 RCDs.
Dual RCD Consumer Units - A consumer unit with 2 x RCDs which may be different or the same amperages.
17th Edition Consumer Units - Typically, a consumer unit with 2 RCDs and Main Switch.
Insulated Consumer Units - Consumer units with plastic enclosures, usually in domestic environments.
Metal Consumer Units - Consumer units with metal enclosures, used in garages for example.
Main Switch Consumer Units - Consumer units with 100A Main Switch only.
High Integrity Consumer Units - Special consumer units which feature 3 bus bars and allows for independent earth leakage protection.

'17th Edition Consumer Units' - The Most Misunderstood Term in UK Electrics
The term '17th Edition Consumer Unit' is now one of the most commonly used and misunderstood in the UK Electrical vernacular. Through lack of industry conformity the term has come to mean a consumer unit supplied with two RCDs. BUT: This does not necessarily mean the consumer unit abides by 17th Edition Regulations and certainly does not mean that other consumer units are not 17th Edition compliant.

Let us first remind ourselves of what the 17th Edition Regulations actually mean in terms of circuit protcetion: The 17th Edition regulations state, quite simply that all circuits must be protected against earth leakage, which means in layman’s terms that individuals are protected against electric shock.
 
This may be done by using an RCD (Residual Current Device), which protects a bank of circuits against earth leakage simultaneuosly or an RCBO (Residual Current Breaker with Overload protection), which protects an individual circuit.
 
Every installation is different depending upon a number of variables including the number of circuits, the types of device being protected on each circuit, the loads on individual circuits and of course the customer’s budget. For this reason all consumer units are configurable upon installation and may therefore protect against earth leakage using a combination of RCDs, RCBOs or both.
 
In general each of the four generic designs of UK consumer unit; Main Switch, Split Load, High Integrity and Dual RCD all meet the requirements of the 17th Edition. However, depending on the installation variables it becomes apparent that some designs offer greater compliance than others by enabling better ‘Division of Installation or separation of circuits, which prevents ‘nuisance tripping’.
 
To clarify the situation the UK consumer unit manufacturer Wylex has introduced a ‘5 star’ system, akin to that used by hotels, to grade 17th Edition compliance. Ironically, the very consumer unit which has over the last two years been marketed as a ‘17th Edition Consumer Unit’, is the one which scores lowest with only 2 stars.
 
The Dual RCD consumer unit was originally considered the best way to [ cheaply ] satisfy the 17th Edition Regulations, which is why they became known as ‘17th Edition Consumer Units’. But this configuration does not allow for any separation of circuits and therefore crucially, does not allow for a separate smoke alarm circuit and makes no provision for nuisance tripping.
 
Under the Wylex system the only type of consumer unit which scores five stars is the older type Main Switch consumer unit as it allows for full loading of RCBOs therefore providing complete independent circuit protection against earth leakage. High Integrity and Split Load consumer units both score 4 stars as they allow for a certain amount but not complete, circuit division.
 
In summary, a consumer unit cannot inherently be ‘17th Edition’ and this has become a misleading if not dangerous misnomer. Only when it is installed and loaded according to the 17th Edition Regulations and having taken into account the specific installation variables can a consumer unit be considered ‘17th Edition’.

Consumer Unit Wiring
The first edition of the IEE wiring regulations was published as a simple four page document in 1882 by the Society of Telegraph Engineers and Electricians, which later became the Institution of Electrical Engineers (IEE). Consumer unit wiring must adhere to the strict guidelines set out in these regulations. Introduced on July 1st 2008, the 17th Edition of the Wiring Regulations (BS7671 - 2008) have now superced the 16th edition. From July 1st 2008, all consumer unit wiring work in England, Wales, Scotland and Northern Ireland must protect against earth leakage. Consumer Unit Wiring has thus changed significantly, as all circuits must now be protected by either an RCD or RCBO. Consumer unit wiring undertaken before July 1st 2008 is exempt.

Hager Consumer Units
Hager is a name synonomous with quality and innovation. With a product portfolio unrivalled in both size and fucntionality, Hager has been one of Europe's leading circuit protection brands for the last 50 years. Hager consumer units boast a range of features, such as extra cable preparation room, integral spirit level and reseallable top lids which make Hager consumer units the choice of the installer.

Wylex Consumer Units
Wylex was founded in 1897. The Wylex consumer unit was the first one to be introduced to the electrical industry. This original preceded the ‘Standard Range Wylex Consumer Unit’, which is still very popular today. Through continuous technological innovation, Wylex consumer units are the market leader in the circuit protection sector. They work very hard to meet the practical requirements of both the contractor and homeowner. We are now stocking the 17th edtion Wylex Consumer Units, including the new High Integrity fuseboards with dual RCD. For more information on Wylex Consumer Units please visit the Wylex Consumer Units.

Consumer Unit Protection Devices and Accessories - A Glossary
 
Main Switch
This is the ‘Double Module’ device which sits on the far right hand side of a consumer. It usually has a big red bar switch and acts to isolate the entire board. This means that by manual operation it can cut power to every circuit in the installation. Main Switches are almost always rated at 100 amp, allowing it to isolate an installation which pulls no more than 100 amps in total across all circuits.
 
MCB
Mini Circuit Breaker. An MCB protects its circuit against overload. When for example a bulb blows on a lighting circuit the MCB cuts the power to the that circuit, thus protecting the other lights. No other circuits on the consumer unit have been affected. An MCB does not protect people against electric shock.
 
RCD
Residual Current Devices protect multiple circuits against earth leakage. This is a vital function of a consumer unit as it is earth leakage which causes electrical shock. RCDs measure the amount of electricity flowing into the consumer unit against the amount flowing out. When it detects an inbalance between the two it cuts the electricity supply to the bank of circuits it’s protecting.
 
It should be noted that this means that a fault on one circuit will result in a cutting of the power to any other circuit protected by that RCD. For example an RCD may protect the ring main and indoor and outdoor lighting circuits. In this instance a fault on the outdoor lighting circuit will knock out the indoor lighting and all power sockets.
 
It is for this reason that the 17th Edition Regulations demand ‘Division of Circuits’ to avoid ‘Nuisance Tripping’
 
RCBO
Residual Current Breaker with Overload (RCBO). This clever device combines the functionality of an MCB and RCD and therefore allows for independent protection on individual circuits against both overload and earth leakage.
 
Din Rail
The mounting rail upon which are fitted the Main Switch, RCDs, MCBs and RCBOs.
 
Busbar
The device which connects electrically the Main Switch, RCDs, MCBs and RCBOs.
 
Neutral Bar
The terminal bar which accepts all the neutral wires from the RCBOs and MCBs.

Contactor - A contactor is an electrically controlled switch used for switching a power circuit. A contactor is activated by a control input which is a lower voltage / current than that which the contactor is switching. Contactors come in many forms with varying capacities and features. Unlike a circuit breaker a contactor is not intended to interrupt a short circuit current. Contactors range from having a breaking current of several amps and 110 volts to thousands of amps and many kilovolts. The physical size of contactors ranges from a few inches to the size of a small car. Contactors are used to control electric motors, lighting, heating, capacitor banks, and other electrical loads. A contactor is composed of three different systems. The contact system is the current carrying part of the contactor. This includes Power Contacts, Auxiliary Contacts, and Contact Springs. An electromagnet system provides the driving force to close the contacts. The enclosure system, is a frame housing the contact and the electromagnet. Enclosures are made of insulating materials like Bakelite, Nylon 6, and thermosetting plastics to protect and insulate the contacts and to provide some measure of protection to personnel coming in contact. Open-frame contactors may have a further enclosure to protect against dust, oil, explosion hazards and weather.
    Contactors used for starting electric motors are commonly fitted with overload protection to prevent damage to their loads. When an overload is detected the contactor is tripped removing power downstream from the contactor. Some contactors are motor driven rather than relay driven and high voltage contactors (greater than 1000 volts) often have arc suppression systems fitted (such as a vacuum or an inert gas surrounding the contacts). Magnetic blowouts are sometimes used to increase the amount of current a contactor can successfully break. The magnetic field produced by the blowout coils force the electric arc to lengthen and move away from the contacts. The magnetic blowouts in the pictured Albright contactor more than double the current it can break from 600 Amps to 1500 Amps.
    Sometimes an Economizer circuit is also installed to reduce the power required to keep a contactor closed. A somewhat greater amount of power is required to initially close a contactor than is required to keep it closed thereafter. Such a circuit can save a substantial amount of power and allow the energized coil to stay cooler. Economizer circuits are nearly always applied on direct-current contactor coils and on large alternating current contactor coils. Contactors are often used to provide central control of large lighting installations, such as an office building or retail building. To reduce power consumption in the contactor coils, two coil latching contactors are used. One coil, momentarily energized, closes the power circuit contacts; the second opens the contacts. A basic contactor will have a coil input (which may be driven by either an AC or DC supply depending on the contactor design) and generally a minimum of two poles which are controlled.

Controller - Any device which controls the function of another

 

Dado Trunking

Datacoms

Desk Fan

Dichroic

Double Insulated - see Cable

Ducting - The tubing used in conjunction with an extractor fan to transport 'old' air outside. Typical domestic ducting comes in four or six inch. The length of ducting used is dictated by the power of the fan.

DIN Rail - A DIN rail or top-hat rail is a standardized 35 mm wide metal rail with hat-shaped cross section. It is typically used for mounting miniature circuit breakers inside consumer units and distribution boards.

Distribution Board 

Earth

Earth Block

Earth Clamp

Earth Rod

Earth Tag

Electrician

Electricity

Electromagnetic Force - Electromagnetic force is the force that the electromagnetic field exerts on electrically charged particles. It is the electromagnetic force that holds electrons and nuclei together in atoms, and which hold atoms together to make molecules.

Electromotive Force - Electromotive force (emf) is the amount of energy gained per unit charge that passes through a device in the opposite direction to the electric field existing across that device. It is measured in volts

Emergency Lighting - Lighting which operates using an integral battery in the event of a break to the electrical circuit. Commonly used in the event of fire in buildings, emergency lighting can be either 'maintained' or 'non-maintained'. The former refers to a light fitting which is constantly illuminated, whilst a non-maintained emergency fitting only comes on when mains power is lost.

Enamel

Energy

Extension Reel

Extension Screw

Extension Socket

Extractor Fan - A device used for extracting stale, polluted, humid or hot air from a room. Seen in bothe domestic and commercial environments. Typical domestic use includes kitchens and bathrooms and utilise 4" or 6" impellars. Commercial and Industrial fans are much bigger in order to move more air from a typically larger space.

Extractor Fans Buyer's Guide

It is essential to install an extractor fan in the bathroom. Preventing condensation build up, damp, mould and odour, a simple 4 inch bathroom extractor fan will help to keep your bathroom beautiful! We keep over 40 different bathroom extractor fans in stock from Vent Axia, Manrose, Airflow and GET, including extractor fans with timers, fans with PIRs, humidistat extractor fans, SELV bathroom extractor fans, slimline fans, and inline fans. This wide choice of bathroom extractor fan can be bewildering, so we've compiled a buyer's guide to help you choose the right bathroom fan.

1. Wiring regulations and Bathroom Zones
2. Extractor Type
3. Size
4. Air Extraction Rate
5. Operation
6. Noise
7. Gil-lec recommends

1. Wiring regulations, bathroom zones and bathroom extractor fans
Since electric and water can make for a fatal combination, strict regulations were introduced dividing the bathroom into 4 zones: 0, 1, 2, 3. Zone 0 is in the bath. Zone 1 extends vertically 2.25m above the bath. Zone 2 extends in all directions for 0.6m from zone1 and zone 3 extends laterally for 2.4m from zone 2.

It is essential that you install the correct bathroom extractor fan in the correct zone. Bathroom extractor fans come in two voltages; Mains voltage (240v) and SELV or Safety Extra Low Voltage (12v) .  Mains voltage bathroom extractor fans may only be used in Zone 1 of the bathroom if they are rated to IPX4 and 1) all circuits in the bathroom are 30mA RCD protected, 2) disconnection times are met and 3) provided they have sufficient means of isolation. An example of this type of fan is the Airflow QuietAir: A mains voltage bathroom extractor fan that has been specifically designed with an IP45 rating to be used in all 3 zones.

More commonly in Zones 1 and 2, SELV bathroom fans (12 volt) are usually used, with the transformer being housed in Zone 3. 

Inline fans are another special type of 240v bathroom extractor fan which are housed in the loft space above the bathroom in the middle of two lengths of ducting. Since the motor, impellars and all electrical parts are out of the zonal area, with only the duct and grille in the bathroom ceiling, they too are suitable for use in zone 1 or 2 above the bath or shower.

2. Types of bathroom extractor
There are two main types of bathroom extractor fan: Axial and Centrifugal. Axial extractor fans are the ones that you are used to seeing on walls and ceilings and tend to have air extraction rates of between 85m3/hr and 95m3/hr on the 4 inch models. These are suitable for standard installations where the bathroom extractor fan is intended to be ducted through the wall. Centrifugal fans tend to be (but not always) inline duct fans. (see previous section). Centrifugal fans are usually much more powerful than axial fans with air extraction rates of bewteen 110m3/hr and 220m3/hr on the 4 inch models. Centrifugal bathroom extractor fans are particularly well suited to installations where long duct lengths are required. The Vent Axia Solo Plus bathroom extractor fan, for example, can be used in duct runs up to 50m!

3. Sizes of bathroom extractor fans
Domestic bathroom extractor fans come in two sizes: 4 inch /100mm and 6 inch / 150mm. In almost every case a 4 inch bathroom extractor fan will suffice.

4. Air Extraction Rate
Measured in 'Litres per Second' (L/s) or 'Metres Cubed per Hour' (m3/hr), the air extraction rate of a bathroom extractor fna is one of the most important considerations. The Building Regulations stipulate that a bathroom extractor fan must extract at least 15L/s in a standard domestic bathroom. Most 4 inch bathroom extractor fans far exceed this minimum requirement. (indeed all the bathroom extractor fans stocked by Gil-lec do!). Any bathroom extractor fan with an extraction rate of 85m3/hr or above is powerful.

5. Operation
Bathroom extractor fans have a range of operational features to suit different applications. The most simple is on/off via the bathroom light switch or integral pullcord. Landlords may prefer bathroom extractor fans with humidity sensors, which switch on automatically when the relative humidity reaches a set level. This means that tenants are not relied upon to manually operate the bathroom fan. Bathroom fans with integral timers are great in bathrooms where large build ups of steam cause condensation problems. Parents may prefer a bathroom fan with a PIR sensor which will operate the extractor fan automatically when anybody enters the bathroom.

6. Noise
Typical dB measurements for axial bathroom fans range between 35dB(A) and 45dB(A) with the more powerful centrifugal bathroom fans between 40dB(A) and 55dB(A). Whilst centrifugal extractor fans are louder, it should be remembered that they are housed in the loft space and so are insulated and further away, lessesning the volume somewhat. If noise levels are a prticular consideration then we recommend the Airflow Quietair, which on full power operates at only 25dB(A)

7. Gil-lec Recommends
1. All round best bathroom extractor fan: Airflow QuietAir. Because: It is powerful, very quiet, low energy and IP45 rated is suitable for all bathroom zones.
2. Best Looking bathroom extractor fan: Airflow Icon with the 'opening eye louvres', Vent Axia Silhouette - super slim, Manrose Deco, Airflow QuietAir
3. Most Powerful bathroom extractor fan: Axial 4 inch: GET GFAN4T 93m3/hr. Centrifugal 4 inch : Vent Axia ACM100T 220m3/hr
4. Best Value for Money: GET GFAN4T: 93m3/hr - £14.79 inc vat!

Fan
Clip on Fan Type of cooling fan with sprung clip attachment. Usually only available with 6 inch impellar.
Desk Fan Small Cooling Fan with base used in office and domestic environments. Typical sizes include 6, 9, 12 and 16 inch.
Extractor Fan A device used for removing old stale air from a room. Seen in all types of environments from domestic bathrooms to bars, pubs and factories.
Pedestal Fan A larger cooling fan, usually with 16 inch impellar, which has its own stand.

Fibre Optic

Finish

Fire Panel - Term used to describe the device which alerts of potential fires. Usually mutli-zonal, the control panel is used in conjunction with call points, sounders and detectors.

Flex

Friedland - Manufacturer of door entry systems, and stocked at Gil-lec

Fuse - In electronics and electrical engineering a fuse, short for 'fusible link', is an overcurrent protection device. It has as its critical component a metal wire or strip that melts when heated by a prescribed electric current, opening the circuit of which it is a part, and so protecting the circuit from an overcurrent condition.

Fuseboard

Galvanised

Gang - the term applied to the number of switches (or sockets) on a plate. For example, 3 Gang Dimmer, means there are three individual switches on a plate, whilst 2 Gang socket would describe a plate with two sockets. Confusingly however, in common parlance, 'Gang' is also used in reference to the size of plate or box, such that a 1 Gang box will take a 3 Gang Switch. (This is because a 3 Gang Switches are available in single plates)

Gil-lec - A forward thinking, innovative, customer focused, National UK electrical wholesaler selling goods and providing a wealth of information online.

Gland

Green Products - Energy saving devices, such as low wattage lamps

Grip

GU-10 - A type of lamp cap recognisable as a ceramic round edged base with two parallel metal studs. Since a GU-10 cap is only ever used on one type of lamp, the mains halogen spotlight known as a 'Hi-Spot', these terms are now widely used interchangably. GU-10 lamps use aluminium reflectors which send the heat back into the luminair.

GZ-10 - A type of lamp cap recognisable as a ceramic square edged base with two parallel metal studs. GZ-10 caps are less common than GU-10s but are easily confused as they look very similar. A GZ10 is differentiated by its square edges (a GU-10 has a round edged base). GZ10 lamps were designed with dichroic reflectros which sned the heat of the lamp away from the luminair.

Halogen

Halophosphate

Hex Bolts

Hilux

Hi-Spot - Term given to the mains halogen lamps used in domestic downlights and range from small 35w GU10 lamps up to 100w Par30 lamps

Honeywell - Manufacturer of thermostats and controllers stocked at Gil-lec

Horstmann - Manufacturer of thermostats and controllers stocked at Gil-lec

HVAC System - HVAC (pronounced either "H-V-A-C" or, occasionally, "H-VAK") acronym that stands for "heating, ventilating, and air conditioning". This is sometimes referred to as climate control and is particularly important in the design of medium to large industrial and office buildings such as sky scrapers and in marine environments where humidity and temperature must all be closely regulated whilst maintaining safe and healthy conditions within. In certain regions (e.g., UK) the term "Building Services" is also used, but may also include plumbing and electrical systems. Refrigeration is sometimes added to the field's abbreviation as HVAC&R or HVACR.

Intelligent Building Controls

Intermediate Switch

Ionisation Smoke Alarm

IP Rating - 'Ingress Protection' rating states the level of resistance to solids and liquids, such as dust and water an electrical item has. IP ratings are only witnessed in certain electrical items where relevant, such as outdoor switches and showerlights for example. IP ratings use two digits (i.e IP44, IP68 etc) The first digit relates to foreign bodies, the second to liquid. The definitions are as follows:
First Digit - Foreign Bodies
0 : No Protection
1 : Protected against solid objects greater than 50mm i.e touch by hands
2 : Protected against solid objects up to 12mm i.e fingers
3 : Protected against solid objects greater than 2.5mm i.e tools and wires
4 : Protected against solid objects greater than 1mm i.e small tools and wires
5 : Protected against dust, limited ingress
6 : Totally protected against dust
Second Digit - Liquids
0 : No Protection
1 : Protection against vertically falling drops of water i.e condensation
2 : Protection against direct sprays of water up to 15 degrees from vertical
3 : Protection against direct sprays of water up to 60 degrees from vertical
4 : Protection against direct sprays of water from all directions - limited ingress
5 : Protection against low pressure jets of water from all directions - limited ingress
6 : Protection against high pressure jets of water from all directions - limited ingress
7 : Protection against the effects of immersion between 15cm and 1m
8 : Protection against long periods of immersion under pressure
Common IP Ratings - Although there are numerous combinations of IP ratings the most common are IP44, IP65 and IP68

Isolator

J

 

MCB - Abbreviation for 'Miniature Circuit Breaker': an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city.

Metal Halide Lamps - A member of the high-intensity discharge (HID) family of lamps, produce high light output for their size, making them a compact, powerful, and efficient light source. Originally created in the late 1960's for industrial use, metal halide lamps are now available in numerous sizes and configurations for commercial and residential applications. Like most HID lamps, metal halide lamps operate under high pressure and temperature, and require special fixtures to operate safely. They are also considered a "point" light source, so reflective luminaires are often required to concentrate the light for purposes of the lighting application. 

Multi Room - see Multi Zone

Multi Scene - The term given to the functionality of Intelligent LIghting Systems which stores the dimming settings of multiple lighting circuits. These different dimming settings are known as scenes, and are typically used to create different lighting effects and moods or for different functions, such as watching TV, reading or entertatining. 

Multi Zone - The term given to building management systems which operate functions, (commonly lighting) in different areas

 

Non-Maintained - Term given to Emergency Light Fittings that do not stay illuminated until mains power fails. (see also, Maintained) 

 

 

Optical Smoke Alarm - see Alarm

Osram - World renowned manufacturer of lighting equipment and lamps

Overload Relay

Part P - UK law, effective Jan 1st 2005. Requirement P covers fixed electrical installations in dwellings. It is intended to increase the safety of households by improving the design, installation, inspection and testing of electrical installations in dwellings when these installations are being newly built, extended or altered.

Passive Infra Red - A device used for detecting movement. Typical application is the switching of lights, particularly used as a convenience or security device. PIRs come in a range of detection widths, from 90 degrees to 360 degrees, with a range of detection lengths from 5m up to 30m and may be adjusted to switch lights for set periods of time

PAT Testing - Portable Appliance Testing

Patress - Another name for a surface socket or switch box. Commonly in moulded plastic, surface pattresses are designed to be used with a socket or switch of the same manufacturer

Photocell - A device which measures lux levels. Typical application is the automatic switching of outdoor lights when dusk falls. Some photocells are adjustable, so that they switch at different lux levels and for different periods of time. They can be wired such that a normal switch can overide their function.

PIR - see Passive Infra Red

Programmer

Portable Air Conditioner - A portable air conditioner or portable A/C is an air conditioner on wheels that can be easily transported inside a home or office. They are currently available with capacities of about 6,000 to 25,000 BTU/h and with and without heaters. Portable air conditioners rely on ducting to carry 'old' air away from the conditioned area, and thus need to be located near a suitable vent. Typically a window or door.

Programmable Thermostat - A programmable thermostat is a thermostat which is designed to adjust the temperature according to a series of programmed settings that take effect at different times of the day.

 

Rawl Bolts

Rawl Plugs - A type of fixing used in building which allows screws to be fitted into masonry walls. The hole is first drilled to accept the rawl plug into which the screw is fixed. The original wall plug, the Rawlplug, was invented by J J Rawlings in 1919, and the name has become genericised in the UK, applied to wall plugs from competing manufacturers. Early wall plugs were thick-walled fibre tubes, but most current brands are plastic.

RCCBO

RCCB See RCD

RCD - Residual Current Device is an electrical wiring device that disconnects a circuit whenever it detects that the flow of current is not balanced between the phase conductor and the neutral conductor. The presumption is that such an imbalance may represent current leakage through the body of a person who is grounded and accidentally touching the energized part of the circuit. A shock, possibly lethal, is likely to result from these conditions; RCDs are designed to disconnect quickly enough to prevent such shocks. Available in a range of current sizes and 'breaking capacities' RCDs can be found in consumer units, distribution boards, as plug-in units, (used to protect domestic garden devices for example) and as integral devices to other switches, such as the 'RCD protected socket'. Also known as residual current circuit breaker (RCCB), though this term is principally used in relation to fuseboard scenarios.

Red Grey - Manufacturer of trailing sockets and extension reels

Relay - A relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact. The movement either makes or breaks a connection with a fixed contact. When the current to the coil is switched off, the armature is returned by a force approximately half as strong as the magnetic force to its relaxed position. Usually this is a spring, but gravity is also used commonly in industrial motor starters. Most relays are manufactured to operate quickly. In a low voltage application, this is to reduce noise. In a high voltage or high current application, this is to reduce arcing.
    If the coil is energized with DC, a diode is frequently installed across the coil, to dissipate the energy from the collapsing magnetic field at deactivation, which would otherwise generate a spike of voltage and might cause damage to circuit components. Some automotive relays already include that diode inside the relay case. Alternatively a contact protection network, consisting of a capacitor and resistor in series, may absorb the surge. If the coil is designed to be energized with AC, a small copper ring can be crimped to the end of the solenoid. This "shading ring" creates a small out-of-phase current, which increases the minimum pull on the armature during the AC cycle.

By analogy with the functions of the original electromagnetic device, a solid-state relay is made with a thyristor or other solid-state switching device. To achieve electrical isolation, a light-emitting diode (LED) is used with a photo transistor.

 

Retractive Switch

Remstrap - A particular type of cable clip used for holding armoured cable. Also known as cleats.