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Security Alarm installation, Maintenance & Servicing

Posted by RJA Electrical Services on January 14, 2016 at 10:50 AM Comments comments (0)

Security Alarm installation, Maintenance & Servicing

Alarm Systems providing a range of services to protect your home, your property and your family. We only use the highest standard alarm and intruder manufacturers, so you can rest assured that your security alarm system will be good quality and the very best in the latest security technology.

 

Whether you are looking for a comprehensive burglar alarm or TV monitored CCTV (closed circuit television) setup or an intruder alarm system. Our fully qualified and certified engineer can help. we can give you that peace of mind with a range of low cost packages that can’t be beaten..

There are several ways a fire can start:

Posted by RJA Electrical Services on November 30, 2015 at 6:25 PM Comments comments (13)

Loose connection under heavy load. This raises resistance, which has the effect of raising the voltage beyond the rating of the wire. I have seen 3 pin plug sockets catch fire because of this.

Shorts. Many causes here, but a short is, in effect, arc welding. As you can imagine, this is very hot and fires can start quickly in old wooden houses.

Too much load on the circuit. Usually, this is a “home fix” problem, where somebody puts in a circuit breaker rated to more amps than the wire gauge amp rating. The wire is being asked to carry more power (watts) than it should, which can cause the wire to heat up. If the overload is bad enough, the heat will catch the insulation on fire.

Poor grounding can cause fires. It tends to be less of a direct fire issue than a real safety problem. Poor or no grounding can kill by electrocution in cases where your body becomes the best path back to the box or earth.

Wiring in poor condition or with inappropriate fusing may cause fire where the fuse does not ‘blow’ in time to prevent excessive heat buildup, and ignite surrounding materials.

The heat generated by lamps and heating elements too close to flammable materials is another major cause.

How does bad wiring cause fire?

Posted by RJA Electrical Services on November 30, 2015 at 6:20 PM Comments comments (0)

wiring causes fires and in many cases people lose their most valuable asset because they ignored the safety of the electrical systems in their house. The easiest step you can take in reducing the risk of electrical fires, is to avoid overloading your home’s electrical circuits.

Each circuit in your home is only designed to deliver so much electricity, and stressing these circuits by drawing too much power can cause the wires to spark or deteriorate.

Replace any old wiring in your home. Electrical wiring only has a lifespan of about 30 or 40 years, so homes older than that may be relying on deteriorated wiring. In addition, older wiring setups were not typically designed to handle today’s large electrical loads. If you are relying heavily on extension cords or if your circuit breakers trip regularly, you are likely drawing more power than your old wiring can handle.

Older homes may contain old compound wiring, which poses a more significant risk of degrading and causing fires than copper wiring.

Having RJA Electrical Services replace all or most of your home’s wiring will provide a virtual guarantee against electrical fire

If your home is very old, it may have very few circuits, as plug-in appliances and equipment were not as numerous when the home was built. An effective measure to reduce stress on each circuit is to have an electrician from us come to you and run new wiring and install new circuit breakers on your electrical panel.



how to fit a spotlight - mains voltage

Posted by [email protected] on August 23, 2015 at 4:45 PM Comments comments (0)

 

If you want to replace your pendant ceiling light with recessed spotlights, start by installing the lights and running 1mm² of two-core-and-earth cable back to the position of the ceiling rose. For each extra light, you'll need to split the supply cable at a three-terminal junction box, and connect the matching cores at each terminal. Clip the new cables neatly to the sides of the joists.

 

 

Safety first - Spotlight and transformer heat

 

 

Because spotlights (and particularly transformers) can get very hot, they're a potential fire risk if there's not enough ventilation. So always pull any insulation material well clear of the fitting, and fit specially designed heat diffusers to your down lighters. If your transformer is hidden in a ceiling void, you must be able to get to it from the floorboards above or a trap door below. It's worth checking the manufacturer's instructions before fitting a transformer, as some aren't designed to operate in an unventilated ceiling void. In a loft, it's a good idea to protect your fittings from accidental damage by building a plywood box around them - but be sure to leave the top open for ventilation. In some situations, the Building Regulations state that all recessed ceiling lights must be enclosed in fire-proof compartments, even when they're installed in a multi-occupancy building.

Step 1

After isolating the lighting circuit and double-checking the power is off with a voltage tester, disconnect the cable or cables from your existing ceiling rose. If it's a loop-in system, label the cables so you can see which are the circuit cables and the switch drop. There should be a length of brown sleeving on the blue core of the switch drop cable (the black core, if your wiring is in the old colours) that's connected to the live (brown) core of the flex to the light.

Step 2

Unscrew the rose base plate and push the cables back through the ceiling.

Step 3

If a single cable supplied the old rose, connect it to the new cable for the spotlights through a three-terminal junction box. If you find two or three cables, connect these to a four-terminal junction box.

Step 4

At the spotlights, strip the outer sheathing of the supply cable, expose the ends of the cores and connect them to the light. Make sure you've positioned the spring clips correctly and push the light into its hole. Then check the clips have engaged the plasterboard and are holding the light firmly in place.

Step 5

Complete the job by repairing the hole where the ceiling rose was with filler, if you need to. Sand it smooth when it's dry, and then paint it.

 

 

Fluorescent bulbs

Posted by [email protected] on August 23, 2015 at 4:45 PM Comments comments (0)

Fluorescent bulbs

 

Also known as Compact Fluorescent Lamps (CFL), these are often referred to as 'energy saving' bulbs.

 

The benefits of the technology are that they produce a bright white light, but only use 20% of the energy that a standard incandescent bulb would.

 

Pros

•80% energy saving over incandescent equivalent

•Low running costs

•10 x longer lifetime than incandescent bulbs (approx. 10,000 hours)

 

Cons

•Slightly harsher light than incandescent

•Can take up to 2 minutes to reach 100% brightness

•Generally non-dimmable

•Most contain traces of mercury so require careful disposal

•Bulbs tend to be larger than the incandescent bulbs so may not be suitable for all light fittings

 

Halogen bulbs

Posted by [email protected] on August 23, 2015 at 4:45 PM Comments comments (0)

Halogen bulbs

 

This technology was developed from spotlight bulbs and car headlamps, using a gas to produce a brighter light from less electricity.

 

Pros

•Cheapest to buy of the 'New Era' technologies

•Familiar warm light

•Dimmable

•Same look and size as traditional incandescent bulbs

•Full brightness instantly

•Uses 2-25% less energy than incandescent bulbs

•Contains no harmful chemicals

 

Cons

•More expensive to run than other 'New Era' technologies

•Still inefficient (only 20% energy saving vs incandescent)

•Short lifetime (approx. 2,000 hours)

 

Light bulb buyers guide

Posted by [email protected] on August 23, 2015 at 4:40 PM Comments comments (0)

Common cap fittings

Bayonet cap

The UK's most common cap fitting with a push, twist and lock action. Commonly written as BC, the standard size is B22d (which refers to the diameter of the cap) and a B15d is the smaller version, also known as small bayonet cap or SBC.

Edison cap

Edison screw cap

Another regularly used cap fitting with a screw in action. Commonly written as ES, the standard size is E27 and the E14 is the smaller version, also known as small edison screw cap or SES.

 

GU cap

GU caps

Not dissimilar from a bayonet cap, these types of bulb have a push, twist and lock action. The most common of these are the GU10 and the GU5.3, also known as MR16 bulbs.

 

LED bulbs

Posted by [email protected].uk on August 23, 2015 at 4:40 PM Comments comments (0)

LED bulbs

 

LED (light emitting diode) is now the focus of all lighting manufacturers. The technology has existed in many forms for a long time but has only more recently become a truly viable replacement for home lighting.

 

Pros

•Ultra low running costs (90% energy saving)

•Up to 30 x longer than incandescent bulbs (up to 30,000 hours)

•Full brightness instantly

•No harmful materials

•Familiar warm light

•Dimmable options available

 

Cons

•Not all equivalent wattages and shapes are available yet

•Most expensive of the new technologies

 

Did you know?

 

Although the LED itself runs at a low temperature, the electronic circuit inside the bulb will heat up. A heat sink is put in place to keep the LED as cool as possible; the bulb will still become hot to the touch but not nearly as hot as fluorescent, halogen or incandescent bulbs.

 

Socket Outlets - Extending the Ring Main

Posted by [email protected] on May 7, 2015 at 12:55 AM Comments comments (0)

Rather than adding a spur to a ring main to provide an additional socket outlet, it may be advantageous to extend the ring.

Planning the extended ring main

1. Plan for the new socket outlet

As you can see in the digram, this is done by inserting a longer length of cable between two of the sockets on the existing ring, allowing it to be routed and connected to the new socket on the way.

2. 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.

3. Establish the route taken by the ring main and decide upon the two sockets between which it is best to extend.

Adding the new cable

Fitting the new socket box

4. Fit the new socket box at the required position. The method for doing this will depend on whether it is a Surface Mounted Box, Flush Metal Box, or Plasterboard Box.

Cable fed to new socket outlet

5. Lay cable from the first socket, taking it to the new socket position along the way, and on to the second socket. Remember to allow sufficient cable at the position of the new socket for making connections.

Cutting the cable at the new socket outlet

6. Cut the new cable at this point.

7. Strip both the new cable ends ready for connection. See our Cable Stripping Guide for detailed information on this.

Cutting sheath with side cutters

8. Cut through the outer sheath of the cable carefully using a pair of side cutters. Be sure not to cut into the insulation of the conductors.

Cutting the cable sheath

9. Peel back the sheath to reveal the conductors and grip the end of the bare earth conductor with a pair of pliers. Draw the wire back through the sheath like a cheese wire.

Insulating the earth conductor

10. Insulate the earth conductors using the separately sold green and yellow sleeving. This should be cut to length and fed over the conductor so that about 1/2" is left exposed at the end.

Strip insulation from conductors

11. Separate the conductors and trim the insulation of each back by about 1/2" with wire strippers.

Connecting the cables to the new socket outlet

12. Do not twist conductors together before inserting them into the connection as this may damage them and can also cause problems when testing circuits.

13. Slacken the screw of the appropriate connection terminal. Insert the brown (old cable colour = red), live conductors into the hole in the terminal marked ‘L’.

Securing the Live conductors

14. Ensure that the conductor is fully housed and that there is no exposed wire showing. Fasten the screw and make sure the wire is firmly secured.

Securing the Neutral conductors

15. Repeat the process for the blue (old cable colour = black), neutral conductors, fixing them in the terminal marked ‘N’.

Connecting the Earth conductors

16. Repeat the process for the green/yellow sleeved earth conductors fixing them to the terminal marked with the earth symbol.

Metal Boxes Only

Sleeving the Earth tail

17. If you have a metal box like the one shown here, an earth tail may be required. One must be fitted between a socket outlet and metal back box where both socket fixing lugs are adjustable. If this is what you have, cut a suitable length of the earth conductor from some cable of the same size as that used for the circuit. Sleeve this with green and yellow sleeving allowing ½” conductor to be exposed at either end.

Connecting Earth tail to box terminal

18. Connect one end of this earth tail to the earth terminal provided at the back of the metal mounting box.

Connecting Earth tail to socket

19. Connect the other end of this earth tail with the earth conductors secured to the terminal marked with the earth symbol on the socket outlet.

Fixing the socket outlet

Check the connections

20. Double check that all your connections are to the correct terminals, and securely fastened.

Positioning the socket outlet back against box

21. Carefully push the face plate back, gently folding the cables as you go, so that they sit neatly into the box.

Securing the socket

22. Fasten the face plate with its retaining screws. Tighten the screws alternately to draw the plate back evenly.

Using spirit level to align socket

23. As you tighten these, ensure that the face is level. One or both of the screw mountings will have allowance for a small amount of vertical adjustment which assists with this.

Connecting the cables at both original sockets

Releasing the original socket outlet

24. Working on one at a time, remove the face plates of the two sockets between which you are extending the ring main. Slacken the retaining screws and ease the socket outlet away from the wall.

Releasing original cable

25. Establish which cable is the original one travelling between your two sockets and release it’s conductors.

Original cable conductors released

26. With the three conductors (Live, Neutral, and Earth) of the original cable released, the cable can be removed.

Feeding the new cable to the original socket

27. There should now be room to feed one end of your new cable into each of the boxes where you just removed the old one.

28. If not, remove one of the other blanking plates in the box to provide entry for the new cable. For metal boxes you will also need to fit a rubber grommet to the new entry hole. Feed the cable in so that there is sufficient to allow for connection.

New cable stripped and prepared

29. Strip and prepare the ends of the new cable ready for connection. Protect the exposed earth conductor with green/yellow sleeving.

30. Taking the conductors of the new cable, one at a time, insert each alongside the corresponding one from the remaining original cable. Fasten the screw and make sure the wires are firmly secured.

Connecting the new Live conductor

31. Two brown (old cable colour = red) conductors connect to the terminal marked live (‘L’).

Connecting the new Neutral conductor

32. Two blue (old cable colour = black) conductors connect to the terminal marked neutral (‘N’).

Connecting the new Earth conductor

33. Two green and yellow conductors connect to the terminal marked earth (earth symbol).

Earth tail from metal box

34. If these original sockets are mounted in metal boxes where both socket fixing lugs are adjustable there will be an earth tail between the earth terminal on the socket outlet and the earth terminal at the back of the metal box. Ensure that this earth tail is connected back in with the other earth conductors from each of the ring main cables

35. Tighten the screw of each terminal ensuring that the conductors are firmly held and that the insulated part of each butts right up to the terminal.

Fixing the original socket outlets

Positioning the socket back against the box

36. Double check your connections at both these sockets, and ease the face plates back to the boxes folding the cables carefully as you do so.

Securing the socket outlet to the box

37. Re fix the retaining screws, tightening them alternately to draw the fascias back evenly against the surface.

Using spirit level to align socket

38. As you tighten these, ensure that the face is level. One or both of the screw mountings will have allowance for a small amount of vertical adjustment which assists with this.

39. Once you are sure that all work has been completed correctly, switch the power back on at the consumer unit. In the case of removable fuses, replace the fuse for the circuit, and switch the power back on. Check your sockets to ensure they are working properly.

 

Electricity - how it works 2

Posted by [email protected] on May 7, 2015 at 12:55 AM Comments comments (0)

Earth

 

The thing to remember is that the earth (ground we stand on) is a good conductor of electricity. Given the chance of a good conductor and a shorter route, electricity will take it. This means that if you place yourself between the two, it will travel through you to get there.

 

The same happens when a metal object touches the electricity. It is given the choice of a shorter route and will take it.

 

By understanding this principal, you will see the reason for the inclusion of an earth wire in electrical circuits. It provides a direct route to earth in case a fault develops. For example, should a live wire accidentally come into contact with a metal appliance, it will immediately 'earth out'. This change of flow in the system causes the fuses or circuit breakers to 'blow'.

 

double insulated symbolThere is an earth conductor in the cables of circuits as well as in the wires used to connect fitting and appliances. The exception to this is for double insulated appliances which do not need and must not have an earth.

 

Check the labelling on an item for the double insulated symbol.

 

Fuses

 

Fuses are a weak link in a circuit. The wire used in them is thinner than that used in the rest of the circuit. When a fault occurs in a circuit, either through overloading or ‘earthing out’, there will be a significant increase in power through the cables. This causes the thinner fuse wire to heat up and melt. When it does so, it breaks the circuit, switching off the power.

 

The point at which a fuse ‘blows’ is determined by the thickness of the wire. Different sizes blow at different levels of power. They are graded according to the maximum current (measured in amps) which they will support without melting. Exceeding this maximum will cause the wire to break. Nowadays, modern installations make use of ‘circuit breakers’ instead of the old style fuse wires. These devices will detect an increase in the current and automatically switch off the power. The beauty of these is that they can simply be reset at the touch of a button – literally.

 

However, always find and rectify the cause of the fault before resetting a circuit breaker or replacing a fuse. Remember, the fuse has blown for a reason – to tell you something is wrong – don’t ignore it!

 

The two main reasons for a fuse or circuit breaker blowing are: overloading the circuit and earthing fault.

 

 


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