Wiring Diagrams

[zulfim]

Dear Elec Forum
I'm training to be a competent electrician, its proving harder then I thought it would be :whatchutalkingabout
I've completed my C&G 2330 pts 1/2 and 17th edition, the practical training towards the NVQ is a hard slog.

What I am struggling with is the wiring circuits for different switching and applications. For instance, I've been asked to wire 24 Fluorescent lights with two 2-way switches, I'm struggling with this. I don't want to look stupid to my colleagues but at the same time I'm aware of the potential dangers to myself and others if I get this wiring wrong.

Can someone suggest any books or material I can access for the wiring diagrams? I find visual aids a lot clearer then simply being told how to do it.

Thank you in anticipation.

 

[DurhamSparky]

break it down and wire 1 light on the 2 way switching!!

then add lights up to the maximum allowed for the switch then repeat on the other switch!!

 

[Deleted member 26818]

Is this 24 Flourescents all controled by the two way switching, or 24 Flourescents, individually controled by two way switching?
What is to be the wiring type, the installation method and how long is the circuit going to be?

 

[topquark]

I know this wasn't what you asked for, but try drawing it out for yourself. Just start (as DurhamSparky has suggested) with one light, on the single way switching. Then add one more light (being fed from the switched live (not live)).

Then to convert it to two way add in the extra switch and run a 3 core cable between the two switches.

As suggested above, you'll need to take into account the total switching load. To overcome that either provide a multigang switch or use a contactor.

 

[Deleted member 26818]

Or large conductors.

 

[zulfim]

Hi
All 24 lights will be controlled by the two 2-ways switching located near both doors to the large storage area.
Wiring will be done with 1.5mm singles from from the CU protected with three 10A MCBs.

 

[Deleted member 26818]

Will this be over three Phases?

 

[topquark]

Will this be over three Phases?

I wondered that when I saw 3x 10A mcb's ... wasn't in the OP.

 

[zulfim]

Must apologise, new to this forum. Should have explained thing clearer..here goes!
3-phase+N coming off mini bus-bar, into 125A main isolator feeding into 3x10A MCBs then into 3-phase contactor where the coil is protected by a 2A MCB.
Each phase will serve 8 lights (3x8=24)

The intention is to control (on/off) all 24 lights with each switch.

Sorry for the confusion.

 

[oxocube]

Thats going to be a very strange circuit, why a 125 isolator to feed 3x10A mcb? Are the lights going to be 1 x 3ph or 3 x 1ph circuits. For lighting it is best to use latching contactors and they won't work with 2 way switching.

AS to your original question, remember electrical schematics are always drawn as de-energised.

 

[Deleted member 26818]

OK, I would use a 3 phase contactor, installed between the main isolator and the MCBs (this would allow individual isolation of circuits).
The two way switching would then be wired through the contactor control circuit, the same way as you would wire two way switching for a light on stairs.
Only instead of switching the feed to a light, you will be switching the feed to the contactor.
One other thing, what is the wattage of the individual light fittings?

 

[topquark]

Just had a quick nose around on the net, here's a ref for squareD type kit. There's a few diagrams, it may help to sort it out in your mind:
http://www.neweysonline.co.uk/neweys/pdf/Square_D_Control_&_Command_Technical.pdf

 

[Knobhead]

I don’t normally do peoples homework
View attachment 7721

 

[Deleted member 26818]

I see you're showing the fuses before the contactor, Tony.
Will the contactor suffer if any of the phases are isolated?

 

[Knobhead]

No, fuses are always before the contactor. They then protect both the lights and the contactor.

 

[Deleted member 26818]

What I'm asking Tony is, will the contactor suffer any damage, if one or more of the phases are isolated?
It's been a while since I've had much to do with contactors, but I seem to remember that they could become damaged if any of the phases were out of balance, or disconnected for any reason.

 

[Knobhead]

Ahh, got what you’re on about now. If the contactor was feeding a motor then yes removing a fuse will causes problems with imbalance and the O/L’s will trip. But for a lighting circuit you have no O/L’s so a single fuse can be pulled to isolate 1/3 of the loading with no problem.

 

[Deleted member 26818]

Thanks Tony, what about these latching types, that some one suggested being used?

 

[Knobhead]

More bloody trouble than they’re worth, same number of switch wires but two coils to go wrong and all the mechanical bits to jamb up! Don’t even think about it!

 

[oxocube]

More bloody trouble than they’re worth, same number of switch wires but two coils to go wrong and all the mechanical bits to jamb up! Don’t even think about it!

I think you will find that most contactor maufacturers reccommend the use of latching contactors for lighting circuits, you're guessing they know.