Can anyone help me with my understand of circuitry

[jim_lad]

Hi all, I am currently in training as an apprentice electrician, and so am constantly trying to improve my understanding on domestic circuitry, one circuit that bothers me are lighting circuits and the many methods of wiring them, at this present time I can understand how they work but still feel that some level of understanding is missing as they take me forever to work out, so I believe my the problems lies in the understand of the basics of lighting circuits, so if some one can answer these basic questions it would be much appreciated and helpful in building a better mental imagery. What makes the lighting circuits installed in domestic property's a parallel circuit?, and what do all the multiple methods of wiring a lighting circuit have to have in common from start to finish e.g. in all cases the supply must run first from the CU, it then in all of the methods ................., sorry if this seems dumb but something just hasn't clicked yet, thanks in advance

 

[Marvo]

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[snowhead]

A cunningly disguised homework question??

All lighting circuits require a Live, Neutral, and Earth.
They also all require a switch or other control device.

 

[richy3333]

A cunningly disguised homework question??

All lighting circuits require a Live, Neutral, and Earth.
They also all require a switch or other control device.

Don't they also need a BULB?!

 

[Mr.Simple]

Firstly you have to be very careful about what you mean by run in series and parallel. All circuits are run as parallel, and to work correctly each lighting point needs a live, neutral an earth. Essentially these three leave the consume unit and to every lighting point. However you need to be able to switch the lights on and off, and this is were the variations come in.

For a lot of lighting circuits the live, neutral and earth arrives the first "lampholder" and then this is extended to the second, third and so on. These wires should have continuity back to the consumer unit. To switch the lights on and off a cable is then run from the lighting point to a switch, this means that most lighting points wired in this was will have three cables, the one from the consumer unit, the one to the next lighting point and one to the switch. It is usual (I think) t wire the brown wire in the switch cable to the brown wire is the other two cables. This takes the live feed to the switch. At the switch the brown is fed to one side of the switch and the blue to the other. It is REALLY IMPORTANT to realise that this isn't a neutral wire it is live! At the lighting point this wire should be connected to one side of the lamp. The neutral wires are then connected together with the other side of the lamp, and finally all earth wires are connected together.

The other methods are essentially variations of this with the connections being made at other places including in the switch's (I think that this may be frowned upon).

Hope that this helps

 

[Lighthouse Phil]

It is REALLY IMPORTANT to realise that this isn't a neutral wire it is live!

Don't you guys in the UK use brown/brown T+E for the switch drops? (If wiring using the 3plate method)

If using T+E, we use brown / brown T+E,,its made in the UK

 

[longboat]

It's easier and faster to put a bit of brown sleeving over the blue sw.

 

[Lighthouse Phil]

The regs here in Ireland say that the conductor must be the correct colour for its entire length. Silly reg really because as you've said, its easy to put a bit of sleeving on it.

 

[Knobhead]

The regs here in Ireland say that the conductor must be the correct colour for its entire length. Silly reg really because as you've said, its easy to put a bit of sleeving on it.

Makes sense to me. The cheap alternative smacks of indolence.



But then I’m an old fart.

 

[i=p/u]

Most circuits a parrelel as installation electrician. I found the best way to learn was draw them...

 

[Geordie Spark]

Makes sense to me. The cheap alternative smacks of indolence.



But then I’m an old fart.

........... but looking younger since you tidied yourself up a bit, but sadly no prettier..

 

[Hawkmoon]

The regs here in Ireland say that the conductor must be the correct colour for its entire length. Silly reg really because as you've said, its easy to put a bit of sleeving on it.

This is a bit OTT - If you open a switch and become confused by a brown sleeved conductor then you shouldn't be opening the switch in the first place!
I remember (back in the old colour days) an older guy I worked with would never sleeve R/Y/B on 2 ways - his argument was that they were already live coloured conductors.

Though one benefit with using Brown/Brown on switch drops is it makes id at light easy

 

[Knobhead]

........... but looking younger since you tidied yourself up a bit, but sadly no prettier..

I may look younger, I'm still knackered!

At least I’ve still got a full head of hair! (Sort of.) SWMBO is sorting the mess the barber butcher made of it when she finally wakes up. (I’ll be asleep by then!)



Why won't the forum do stikethough in text?

 

[Marvo]

strikethrough

Not sure why it doesn't parse the tags....

 

[telectrix]

The problem with twin brown is which is which. L and S/L. you have to bell out. more time wasted.

 

[Richard Burns]

These are some diagrams that may help with how lighting is normally wired.
You have the descriptions above.

This is some methods of switching lighting:

 

[Knobhead]

The problem with twin brown is which is which. L and S/L. you have to bell out. more time wasted.

30 year since I did my last domestic install, the then red red had a marker stripe on one core. Is it that difficult to bell out? With switch wires it doesn’t make any difference?

 

[telectrix]

maybe not, but i have always followed the practice of L into C and S/L into L1 on switches.

 

[Billythekid]

This is a bit OTT - If you open a switch and become confused by a brown sleeved conductor then you shouldn't be opening the switch in the first place!
I remember (back in the old colour days) an older guy I worked with would never sleeve R/Y/B on 2 ways - his argument was that they were already live coloured conductors.

Though one benefit with using Brown/Brown on switch drops is it makes id at light easy

A particular favourite of mine, especially when they used blue as a neutral. I've lost count how many times that a 2 way switch has been used incorrectly, then some poor sod has replaced it using "standard" wiring method - Pop!!

 

[7029 dave]

Don't you guys in the UK use brown/brown T+E for the switch drops? (If wiring using the 3plate method)

If using T+E, we use brown / brown T+E,,its made in the UK

Yes we used twin red back in the day for spec jobs on switch drops, but sleeving does the job.