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electrician online Qualified electricians : electrical definitions
Alternating Current -(ac) This means the voltage supplied is constantly changing
Amperes - Is the unit of current usually abbreviated as Amps
Back Box- this is the unit to which the faceplate attaches
Cable - Group of two or more insulated wires.
Cable - Coupler/Connector Item designed for connecting or disconnecting two flexible cables one cable has a male fixed to its end connector the other a female
Cable Clips -A means of fixing a cable or cables to a surface
Cable Core - A cable core is the portion of an insulated cable that conducts the electricity lying under the protective covering or coverings.
Catenary wire -Supports the weight of the external cable when linking power from one building to another e.g.. House to shed
Circuit - Interconnection of components to provide an electrical path between two or more components supplied from the same source and with the same overcurrent protection device/s.
Circuit breaker - Is a form of fuse that can be reused. It is designed to break the electrical circuit if there is a chance of it overloading. Stops the flow of current in a predetermined time by means of a coil inside the circuit breaker this creates an electromagnet. The more the current flows, the stronger the electromagnet becomes. If the current gets above the predetermined level , the electromagnetism becomes powerful enough to pull a switch and break the circuit.
Contact - Current carrying part of a switch, relay or connector.
Continuity - Occurs when a complete path for current exists
Continuity - Test A test to verify the continuity of a circuit
Conduit - A protective metal or plastic tube that wires run through.
Compact Fluorescent Lamp- Generally the term applied to smaller diameter fluorescent lamps
Consumer Unit - The hub of a homes electrical system normally where the fuses are installed
Current - Measured in amperes, it is the flow of electrons through a conductor. Also know as electron flow.
Circuit Tester - A meter designed to measure several properties of electricity all in one box. Some circuit testers measure current, voltage and resistance others will also test operating times of RCDs(see also Meter, Ammeter, Voltmeter, Ohmmeter)
Dimmer switch - A switch with a component inside called a variable resistor. As the knob on the dimmer is turned, so the amount of resistance in the circuit gets greater and this makes the current flowing less. With less current a bulb shines more dimly. It will only work with filament bulbs.
DC Power Supply - Any source of DC power for electrical equipment often used on portable equipment e.g. Walkman, radio
Dedicated Radial Circuit - A circuit run directly from the consumer unit (these are mainly used when Installing shower units)
Earthing Systems - The main earthing used in the UK as defined by BS 7671 regulations 312-03 are as follows TN-C, TN-S , TN-C-S , TT and IT.
Fluorescent light - It does not have a filament that glows, but is contains (mercury) vapor that gives off an invisible kind of light called ultra violet light. The ultra violent light strikes particles of a coating on the tube, which then give out visible light (they fluoresce).Very little heat is given out,and more of the power is turned into light this makes a fluorescent tube more efficient and cheaper to operate than a filament light bulb.
Fluorescent tubes can now be made very compact. They are called 'energy saving' lights
Faceplate - The outer part of a socket or switch outlet
Fiber optics Laser's - Light output carries information that is conveyed between two points by thin glass optical fibers these will in the future be used more in domestic situations
Filament Light bulb - Is glass bulb containing a thin metal wire called a filament that heats up when electricity passes through it
Fixture - Any permanently connected light or other electrical device that consumes power.
Fuse - A protective device in the current path that melts or breaks when current exceeds a predetermined maximum value for a given time.
Fuse Wire/Element -The part of the fuse designed to melt
Fuse Holder - Part of the fuse that holds the fuse wire/element
Fuse Board - Place were fuses are located.
Grommet - A washer normally rubber designed to prevent cable coming into contact with metal back box on a switch or socket
HERTZ (Hz.) Unit of frequency. One hertz is equal to one cycle per second
Infrared - Electromagnetic heat radiation whose frequencies are above the microwave frequency band and below red in the visible band ,often used on TV remotes and on alarm sensors
Insulated - When a non conducting material is used to isolate conducting materials from one another.
Insulating material - Material that will prevent the flow of current due to its design and chemical composition
Junction - Contact or connection between two or more wires or cables.
Junction Box- Place where connection between two or more wires cables are housed
Kilowatt-hour meter - A meter used by electric companies to measure the amount of electric power used in your home
Load Current - Current drawn from a source by a load.
Lamp - Device that produces light.
Light filament/bulb - Thin thread of carbon or tungsten which produces heat or light with the passage of current
Live - Term used to describe a circuit or piece of equipment that is on and has current flow within it.
Magnetic circuit breaker - Circuit breaker that is tripped or activated by use of an electromagnet.
Megger - A test instrument for measuring the insulation resistance of conductors and other electrical equipment; specifically, a megaohm (million ohms) meter; this is a registered trade mark of the James Biddle Co.
Meter - Any electrical or electronic measuring device
Overcurrent - Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload, short circuit or ground fault.
Overload - Condition that occurs when the load is greater than the system was designed to handle .Can lead to overheating.
Overload protection - Protective device such as a fuse or circuit breaker that automatically disconnects a load when current exceeds a predetermined value for a given time.
Power Supply - Electrical equipment used to deliver either AC or DC voltage
Residual Current Device (rcd) A mechanical device intended to open the contacts when the residual current reaches a pre determined level for a specific time
Short circuit Low resistance connection between two points in a circuit typically causing excessive current and tripping of overcurrent protection devices
Switch, general use - A switch intended for use in general distribution and branch circuits.It is rated in amperes and is capable of interrupting its rated voltage
Switch - A device for connecting and disconnecting power to a circuit.
Step-down transformer Transformer in which the output AC voltage is less than the input AC voltage.(Often used with lighting)
Step-up transformer -Transformer in which the output AC voltage is greater than the input AC voltage.
Supply Voltage - Voltage provided by a power source/companies
Test Sequence of operations intended to verify the correct operation or malfunctioning of a piece of equipment or system.
Transformer - Inductor with two or more windings. Through mutual inductance, current in one winding called a primary will induce current into the other windings called secondaries.
Troubleshooting - Systematic approach to locating the cause of a fault in an electronic circuit or system
Volt - Unit of potential difference or electromotive force. One volt is the potential difference needed to produce one ampere of current through a resistance of one ohm.
Voltage(V) - Term used to designate electrical pressure or force that causes current to flow.
Voltage Drop - Voltage or difference in potential developed across a component due to current flow
Watt - Unit of electrical power required to do work at the rate of one joule per second. One watt of power is expended when one ampere of direct current flows through a resistance of one ohm. In an AC circuit, true power is the product of effective volts and effective amperes, multiplied by the power factor