Wiring lights in Parallel

[andemz]

I have a question re downlights in parallel. I'm lost

Using the junction box system. On the 1st junction box you will have switch cable... light cable.... circuit cable (from CU) and then circuit cable to the next Junction box. You want the switch cable to turn on all of your downlights but obviously the switch is going to be at the first junction box. How then is the 2nd and 3rd junction box wired as these junction boxes would need to carry the switch also.

A guy from a electric shop stated that it is best to wire them in parallel than in series. I understand that but after when i came out i thought about the above.

So that would then lead me to think that i would need a junction box at least that could accomodate 2 or 3 downlighters. Would it really make that much difference if they come of the first junction box if you were having 10-15 downlights and wire them in series? This would seem a lot more easier to loop the wires into each other.

Any pointers welcome

 

[dingbat]

Dead easy. Wire up the first junction box with circuit in, switchwire then neutral and switched live to light. Then take the live for the next JB from your switched live terminal. The second, and subsequent JB's will then only have linepotential when the switch is closed.

You can't wire your lights in series. They just won't work. Don't do it.



I mean it.

 

[breezer]

christmas tree lights are in series, all dim, take one out they all go out (i am being serious)

look in the for refernce section there is a drawing there of lights in parallel

 

[securespark]

Maybe this is another case where parallel and series are getting mixed up.

Maybe by series, the poster means =========O=======O=======O

where ===== is cable, and O is light fitting.

 

[AdamW]

In the method mentioned by SS here, if that is what you are proposing then you may have problems getting the cable to fit.

I installed some mains voltage downlighters. I used 1.5mm cable to supply each light using JBs. I found that the 1.5mm only just fitted into the connector blocks that ran the flexible wires to the bulb holder. I doubt that two 1.0mm's would have fitted in there.

I can see your concerns, especially with large numbers of lights you would end up with a lot of JBs but this will still be a tidy installation method. Plan where the lights are going, decide where the JBs are going and which lights each JB will supply. With a lot of lights it is less hassle to have more JBs than to try and cram lots of cables into each JB.

 

[ban-all-sheds]

#3 is electrically parallel, but uses more cable than #1, and will be a hassle at the JB.

 

[andemz]

Thanks for the pointers gang, and a big thanks for the diagram although it has left me with more questions in my quest for ever increasing knowledge of electricity and circuits.

From further reading i see how it needs to be in parallel. the live to live to live to live and the same with the neutral i take it that the round things on the diagram are lights i.e downlighters. I also assume (although i shouldn't), that one would use one wire and then earth each light in the appropriate place. It just threw me a bit seeing what seemed to be 2 wires but i figured that it was 1 wire live and neutral in the diagram.

So thanks i think i've got that part i think.

so correct me if i'm wrong. Junction box = Circuit cable (say from CU) Switch cable and then light cable. The light cable live is connected to the switch terminal and the switch cable is connected up as normal using the red tape around the black wire. from there the light cable can then go in parallel one cable live to live to live and so on and the neutral wire from the cable... neutral to neutral to neutral and so on. earth to be connected in appropriate place and cables will terminate as it is radial at the last downlight.

AdamW expressed concerns if i didn't use junction boxes stating that using 2 X 1mm cable may prove difficult as the connector blocks don't provide you with much room. Do others on this forum offerthe same concerns, or are there some downlighters which allow for this in thier manufacturing?

Toughts from others and clarification as to whether i've got my head around this part of my learning is welcome.

 

[AdamW]

AdamW expressed concerns if i didn't use junction boxes stating that using 2 X 1mm cable may prove difficult as the connector blocks don't provide you with much room.

It probably depends on the brand. That was just my experience! Have you already bought the lights? If so you can check.

 

[andemz]

no i haven't purchased them as of yet but i will be in the near future, i guess i will give generous consideration to your experiences as i think that wiring the lights in as on the diagram looks a convienient, practical and still safe way of working.

I presume that i have got the cableing right in my above post?

 

[ban-all-sheds]

From further reading i see how it needs to be in parallel. the live to live to live to live and the same with the neutral i take it that the round things on the diagram are lights i.e downlighters. I also assume (although i shouldn't), that one would use one wire and then earth each light in the appropriate place. It just threw me a bit seeing what seemed to be 2 wires but i figured that it was 1 wire live and neutral in the diagram.

Yup - live & neutral - brown & blue - gotta move with the times... )

so correct me if i'm wrong. Junction box = Circuit cable (say from CU) Switch cable and then light cable. The light cable live is connected to the switch terminal and the switch cable is connected up as normal using the red tape around the black wire. from there the light cable can then go in parallel one cable live to live to live and so on and the neutral wire from the cable... neutral to neutral to neutral and so on. earth to be connected in appropriate place and cables will terminate as it is radial at the last downlight.

Yup - that's fine. I didn't show the earths as it would just have made the diagrams messy, and (if the luminaires need an earth) they're wired the same whether it's a series or a parallel circuit anyway..

 

[andemz]

Thanks, it's more about the learning process for me at the moment and getting comments from others about practice dilemas etc and knowledge on how to complete other tasks. Downlighters seem ever increasing in popularity and i thought that i would learn this.....

 

[andemz]

Maybe this is another case where parallel and series are getting mixed up.

Maybe by series, the poster means =========O=======O=======O

where ===== is cable, and O is light fitting.

This is how i meant it to be as above. Since then i've been to our local electrical store and have stated that some people have problems with fitting 2x 1mm2 cables into the downlighter 1 cable for providing the LNE to the light and the other cable going to the next light.

The chap at the shop was very helpful and said that you could get around the problem of trying to get wires in by using the small 4 terminal 20amp junction boxes. I have drawn a diagram below see what you think and whether in practice it would work.

The black circles are the junction boxes and the red circles are the downlighters.
Also as i understood it that if you have a 6amp MCB protecting your lighting circuit you can only have a max of 1200 Watts on that circuit. Is it safe and common practice to actually have your lighting circuit on a 10amp MCB so that you can take more capacity in the future.

The above diagram is 1mm2 cable what difference would it make if 1.5mm2 cable was used, i take it that you would use 1.5mm2 over a longer distance if it was needed.

 

[breezer]

dont see the point of the junction boxes ( they dont seem to be of any use, apart from jb 1) also 1.5 is better

 

[andemz]

Hi breezer, I've had a good look at it again and see your point, they really wouldn't make any use as you would still need to double up on the wires in the downlighter.

AdamW saw my concerns about fitting 2 wires into the terminals of the downlighters. You say 1.5mm2 breezer given this space for the connections will be tight.

question 1) Have you experienced this issue with space, can we overcome this given that 2 x 1.5mm2 wires will need to be coonected.

2) Whydo you suggest 1.5mm2 over 1mm2.

Thanks

 

[breezer]

1) not usualy a problem

2) not a loyt of price difference, can carry more current, great when you want to add to it