Umair

By using the correct tables.

Before anyone complains that this has nothing to do with a cable, please explain to me what is an "Umair" and how does that relate to a cable?

just another dumb ass response from "always-right said fred".

It seems like sometimes people misinterpret the "Title" field to be a name, personal title, or job title.

Its already discussed many time on this forum, only thing you need to do is make a search, By the way it is the Ampere value that will determine the size of cable not the watt.

It's all in British Standard 7671.

Hi!

Please put up a valid querry as 60 watts load would only require a wire. It would depend, however, I would assume a lighting circuit, so you would need a 10A MCB with a 2.5 mm^2 wire.

If you're running a single lighting point, you could use either a 1CX1.5mm^2 wire or flex cable of 3CX1.5mm^2 (where, 1 wire for phase, 1 for neutral to light point, and a third one to the switch for earthing) ...:) Running wires of size 2x1CX2.5mm^2 would be for a lighting cicuit of upto 1200W run in a conduuit (or trunking). If you want to run expose, then GI steel conduits. Otherwise PVC conduits of 25mm diameter run concealed in wall? :)

Where did the trunking, conduit and wall spring from?

1. 60 watts at 6 volts gives 60/6 = 10 amperes [1950's motor car headlamp?].
2. BS7671 tabulates 11 amp rating for 2 copper wires of 1 square mm cross section with 240 volt, 70 Celsius maximum, PVC insulation, installed in conduit, buried in a wall. But that cable will lose about 0.4 volts for every metre of run length from the battery - using the volt drop per amp per metre run tabulated in BS7671.The lamp brightness will soon fall as the run length is increased over 1 metre. Most "6 volt battery start" cars suffered from poor lighting.........
3. To get adequate voltage at the load, thicker wire must be used, say 2.5 sq mm for 2 metre run.
   

Or for 240V alternating current table lamp:-

1. 60 watts at 240 volts gives 240/60 = 0.25 amperes.
2. If it is a flexible cord for a table lamp, BS7671 has minimum 0.5 sq. mm for copper wire flexible cord (based on mechanical strength/durability needs) which is rated at 3 amperes.
3. So you must use 0.5 sq. mm cord (which is flexible and sheathed overall for mechanical protection to be safe with a movable lamp).

For a 240V fixed lamp, one finds that 1 sq. mm copper is the smallest PVC cable available for house wiring, because a lamp circuit of less than 10 amperes is not standard or convenient for additions and thinner cable lacks robustness.

So you have to know the voltage and the purpose and the length of run - for example, a 12 volt projector lamp gets very hot and needs high temperature cable at its base.

For a many applications, there is a proven, durable, safe and standardized solution for which maximum limits are tabulated in standards, one just looks-up the smallest size rated above the calculated load voltage/current in a table of tested values for the type of installation, then checks the volt drop, increasing section as needed.

Most cable manufacturers give ratings for different conditions in their data and according to standards, sometimes with maximum lengths of run for adequate voltage . Which is very useful, because the standards themselves are expensive to buy. Usually, the national electrical code includes data tables for use of cable to the normal standards used in buildings.

Great reply! Bravo! Thats the way to go :)

The red wire or the live wire goes to the switch terminal, and the black or neutral wire goes to the light holder's terminals. From the switch, run another wire to the light holder's other terminal. This is the switch wire. You can see the Live wire and the Switch wire is actually one single piece of wire, cut off into half by the switch. If the switch is ON, it connects the wire back, if it is OFF, the wire gets cut off again. Thus you can switch the lights ON and OFF.

[Using 1.0mm(square) cable might be a bit cheaper but considering future alterations its always better to use a 1.5mm for later extensions and adding of heavier loads]

The above information is of the internet in support of OUR discussion. If the switch happen to be AWAY from the source (from point to point or Distribution Board in this case) then it would be wise to run the phase wire through the ceiling lighting point conduit (without having to be cut at point) straight to the switch (cut here). Then from switch, the connection phase wire be run back in the pipe (conduit) to the point of light (cut here) off the switch. Neutral straight to the point (cut).

Now, I am very pleased with the detailed reply of yours to the original poster. I must shed some more on how he/she could carry on with the conduit (pipe) question :) It must come from Dubai. In order to all of the above, one must first do the following:

1) Marking in wall

2) For lighting point, the pipe is run before concrete pour (slab). However in wall, cutting in wall by using grinder with steel blade (plate), along the marking area

3) Once cut to the point, then install conduits of 25 mm diameter run

4) Then fill the open area around conduit with mortor slab + pluster

5) Using wire pulling spring, pull & install wires

6) Installation of junction box

7) Wiring accessaries such as switch, ceiling rose, etc

7) Termination of wires into the accessaries and source

8) testing for insulation resistance or continuity (Megger?)

9) Testing and commissioning

Hahahahahahaha.....:)

Did it finally help, Umair??

Yes, you might have helped Umair, in your own way but he hasn't shown the willingness of joining the thread any longer, I suppose?

Umair, if that would please or amuse you any further here you go with material list:

1) Wiring Acessaries (including Ceiling Rose) MK (UK)

2) Flexible Cable -Shercab (i.e. Sharjah (UAE) Cables), Ducab, ME Cables (saudiA)

3) Blocks/Wall etc. Cutting Tool (Grinder) Steel Cutting Blade Size 9 inches or 225mm, Exel, Diamond, 1-phase 230VX25.4mm, Made in GERMANY.

And so on. Hehehehehehehe....