Electric Switch:-

Electric Switch, a device for completing and breaking an electric current, or

for changing the path of a current. Electric switches are among the most common types of control devices and are in wide use wherever electricity isavailable.In its simplest form, a switch consists of two contacts, one fixed and one

movable. When the contacts are brought together, the switch and the circuit are closed and current flows through the circuit. Operating the switch to disconnect the contacts opens the circuit and stops the flow of current. This type of switch, known as a single-pole switch, is commonly used in the homefor turning lights on and off.Three-way switches are of two different types. In one, current is directed to

one or both filaments of a double-filament (threeway) light bulb. The other type is used in pairs to control a single light from two locations, such as the top and bottom of a staircase.

Electric socket:- socket is fixed on equipment or a building structure and

connected to an energised electrical circuit.

Electrical sockets for single phase domestic, commercial and light industrial

purposes generally provide either two or three electrical connections to the supply conductors.

Two pin sockets normally provide neutral and line connections, both of

which carry current and are defined as live parts.Neutral is usually very near to earth potential, usually being earthed either at the distribution board or at the substation. Line (also known as phase or hot, and commonly, but technically incorrectly, as live) carries the full supply voltage relative to theneutral (and to earth).Three pin sockets provide, in addition, a protective earth[14] connection for

exposed metal parts of an appliance. If internal insulation should fail, a short-

circuit to the earthed exposed metal parts will hold them at a low potential,

and should operate fuses or circuit breakers to isolate the faulty appliance from the supply.

Lamp holder:-

Lamp holder types

There are two types of lamp holder, plastic and metal. They may be found as

part of a table lamp, or as a part of a pendant light fitting. The method of

connection is similar for both pendant type and table lamp, but the metal

and plastic types require different considerations.

The first difference to note is that plastic fittings have no earth connection and

should therefore only be connected via a two core flex. Metal fittings

must always be connected via a flex with an earth wire.

Metal versus plastic lamp holders

The second consideration is that metal fittings are not suitable in some

locations – the most notable of which is bathrooms. Plastic ones may be

used in bathrooms, but choose the type with a longer plastic shroud which

shields the components better. In practice, metal lampholders are generally

only used for certain types of table lamps.

Connecting the flex to a lamp holder

1. Switch off the power at the consumer unit for the circuit concerned. If you

have removable fuses at your consumer unit, switch off the power at the

consumer unit and remove the fuse for this circuit. Or, in the case of a table

lamp, switch off and remove the plug from the power supply.

2. Unscrew the fitting to expose the separate components. The construction of

metal and plastic ones is a little different as you will notice from the pictures.

3. Feed the top cover (and retaining pieces in the case of the metal fitting) over

the flex and push them along out of the way.

4. Note the length required for the conductors to reach their terminals, then

strip and prepare the flex. More detailed information can be found in our

Stripping and Preparing Flex article.

5. Using a pair of side cutters, cut back the outer sheath of the flex accordingly

and trim off the excess.

6. Separate the conductors and strip the insulation of each back by about 1/2".

Twist together the separate filaments of each.

7. Connect the brown (live) to one terminal and secure with the retaining

screw.

8. Connect the blue (neutral) to the other terminal and secure with the retaining

screw.

9. Make sure that both are fed round the supports which prevent strain on the

connections.

Earth for metal lamp holders

10. In the case of metal fittings which, as noted earlier, must be earthed, you

will find a small externally mounted earth terminal. This example is a

metal lamp holder on a table lamp.

11. The green and yellow earth conductor is fed to this from inside the fitting

and secured with the retaining screw.

Reassemble the lamp holder

12. Double check your connections then slide the previously threaded

components back down the flex and reassemble the fitting, taking care not

to damage or pull the wires in the process

Wiring a PlugPrepare the plug and flex

1. Open up the new plug by undoing the screw on its base between the

rectangular pins. Inside there will be three terminals, a fuse in a holder and

a clamp for securing the flex.

2. Many new plugs have a template showing precisely how much sheath and

conductor insulation to trim. If yours doesn’t have this you can measure

the lengths as you go.

3. Use a pair of side cutters to cut the outer sheath of the end of the flex.

4. Peel this back and remove the excess with the side cutters.

5. Hold the sheathed section next to the flex clamp and separate the

conductors. Mark the length required for each conductor – allowing for

the actual connection. Cut the conductors to length.

6. Using a pair of wire strippers, trim the insulation of each conductor back by

about 5mm or as detailed on the template.

7. Twist together the individual filaments of each conductor making them

easier to connect.

Connect the wires to the plug

8. Connect the brown conductor to the terminal marked L or live.

9. Connect the blue conductor to the terminal marked N or neutral.

10. If you are fitting a plug to an appliance requiring an earth, you will have a

green and yellow conductor, which should be connected to the terminal

marked with an earth symbol or labelled Earth.

Double insulated appliances

11. If you are fitting a plug to a double insulated appliance (labelled with the

double insulated symbol), you should not have an earth conductor in your flex.

Securing the flex

12. Fit the sheathed section of flex into the clamp (screw type or push fit).This

secures the flex and reduces the risk of the wires being pulled out of

their terminals.

Fitting the fuse in the plug

13. Check what rating of fuse is in the carrier. Most new plugs are supplied

with 13 amp fuses. However, depending on the recommended fuse rating for

your appliance, you may need to change this. Always use the fuse

recommended in the instructions or detailed on the appliance. If no details

are given, use a 3 amp fuse for appliances up to 720 Watts, and a 13 amp for

appliances from 720 Watts to 3000 Watts.

14. Double check all your connections. Replace the cover and fasten with the

retaining screw.

New Light Bulbs - Why the Change?

We are all aware that it is now almost impossible to buy the old style incandescent light bulbs. This is because the government has banned the sale of them and has insisted that all light-bulbs sold in stores arethe low energy type.

The old style bulbs were completely phased out at the

beginning of this year. This puts the UK ahead of other countries in the EU who have until next year toremove the sales of all incandescent bulbs.

There are three types of energy saving bulbs which

can be purchased

•Compact fluorescent lamps - these come in a variety of shapes and are the most common type of bulb

•Energy saving halogen bulbs - These use 30% less energy than standard halogen bulbs.

•LEDs - Good for use in place of spotlights and offer good lighting at low energy levels.

While there has been some controversy regarding this

change, due to the fact that low energy bulbs emit a different sort of light and take some getting used to, the benefits of the new rules cannot be underestimated.

An energy saving bulb is slightly more expensive to buy, however they need to be replaced less often and will make back savings in electricity bills. An energy

saving bulb will last ten times as long as a standard

bulb.

•Energy saving bulbs use just one fifth of the energy of standard wattage bulb. So for a 60 watt bulb you only need an 11 watt low energy one.

Negatives

There has been some concern that low energy bulbs emit a type of light which can give some people headaches. If this is a problem for you, please try some of the other types of bulbs available. LED lightsmay be just what you are looking for.

It is also true that low energy bulbs contain a small

amount of mercury which can be harmful if exposed to skin. Clearly this is only a problem if the bulbbreaks.

Energy Saving Lamps

These are usually compact fluorescent lamps and use less energy than

traditional incandescent lamps. They are able to produce the same

overall level of lighting as standard lamps but, many people find the light

colour to be less than satisfactory. With many low energy lamps, they

take time to warm up and reach full illumination.

Fire Rated Lighting

A range of light fittings designed to meet building requirements in terms

of fire regulations. They may have covers and protective elements to

safeguard against the spread of fire and smoke. Many fire rated

downlights include a smoke hood mounted over the fitting. In lofts and

ceiling voids, the potential spread of fire can be delayed.

Floodlights and PIRs

These lights are designed to provide outdoor lighting and are commonly

controlled by PIR devices which detect movement in the vicinity. This

allows the floodlights to come on only when needed and to provide a

measure of security. Floodlights generally provide a large amount of

illumination over a wide area.

Fluorescent Tubes

Fluorescent tubes are commonly used in offices and shops. Although

they are used in residential properties, this is usually limited to utility

area and garages. The lamps use less energy than standard

incandescent lamps but the light given off is generally not considered

pleasing. The units are frequently fitted with diffusers.

Halogen Lamps

Halogen lamps are commonly used in low voltage downlighters. They

produce a sharp clean light. They can reduce utility bills as they produce

much more light than a standard lamp with the same wattage. They are

known to last longer and have become very popular for domestic

lighting.

HID Lamps

HID stands for High Intensity Discharge and these lamps generate light

by arcing between tungsten electrodes. The gas inside the lamp

facilitates the increased light level produced and, compared to standard

lamps, they give off a greater amount of light for the same wattage.

Incandescent Lamps

Incandescent lamps are what we would all consider to be regular light

bulbs. As an electrical current passes through, the filament is heated

and lights up. There energy consumption is higher than equivalent low

energy lamps and the light output is relatively poor compared to other

lamps available.

Inspection Lights

Inspection lamps are commonly used as work lamps when carrying out

work in poorly lit areas such as attics and under floors. They are often

mounted inside a protective cage reducing the chance of damage. Their

portability enables them to be set up and used easily as and when

required.

LED

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LED stands for Light Emitting Diode and is becoming more commonplace in domestic settings. LED

lamps last well and produce a pleasing light. LED lights produce much less heat than incandescent

lamps and are more energy efficient. Advanced LED fittings can produce changeable light colour

allowing for mood lighting.