Electrical Daisy Chain?

[marsy]

Can anyone please tell me if you lose any power when you wire lights directly from a junction box as opposed to daisy chain..... eg 4 lights from one junction box or 4 lights daisy-chained.... which would be best?
Thanks.

 

[ban-all-sheds]

Depends on lamp voltage and power, size of cable, lengths of cable runs, and positions of lights relative to each other and to ceiling joists etc.

 

[marsy]

Ooooohhhh! If I'd known it was that complicated I would have taken more notice in Physics at school!......
The are 4 lamps, each 50 watts.
The cable is 100mm2.
Each cable is about 2 metres long (from junction box to lamp).
The lamps are in a square layout (imagine a square with sides of about 2 metres). Each lamp is probably within 20cm of a joist.

Does this make it any easier to judge?

Cheers.

 

[ban-all-sheds]

Ooooohhhh! If I'd known it was that complicated I would have taken more notice in Physics at school!......

You can catch up on cable selection here.

The are 4 lamps, each 50 watts.

Voltage? If extra-low, are you talking about the cables for the secondary side(s) of the transformer(s)?

The cable is 100mm2.

No it isn't...

Each cable is about 2 metres long (from junction box to lamp).
The lamps are in a square layout (imagine a square with sides of about 2 metres). Each lamp is probably within 20cm of a joist.

The physical constraints of light/jb/joist positions are for you to judge when looking at the job - is it easier to run from one light to another, or easier to run from a central point to each one individually?

Bear in mind that junction boxes should remain accessible for inspection and testing.