Downlight Wiring

[wassupjg]

Hi guys, super basic question:

For a room layout like this, with my understanding that a lighting circuit downlight radial goes from one point to the next (whereas a socket radial can spur off in multiple directions), would this be acceptable, with the first downlight spurring off to feed two lines of downlights, or would it be "overloading" the first downlight, with 3 tails going in?

Would it be better to use extra cable to feed the 1st downlight on the left and then follow a true radial?

Or a junction box (hager j804) close to the feed splitting into the 2 legs? Maybe avoid a junction box as it's an unnecessary extra junction and therefore potential point of failure?

Cheers!

 

[Taylortwocities]

Firstly, there’s no chance of overloading if you are using LED lamps and standard 1mm cable.
Secondly, your understanding that:
“ downlight radial goes from one point to the next (whereas a socket radial can spur off in multiple directions” is wrong. For this you do not need to go from one to the other. You could cable all the lamps from a single point (in a star arrangement) if you want to.

Often the layout of the ceiling joists will make the decision for you!

 

[ebee]

A radial can take any topology. All you must consider is the total load, in this case its extremely unlikely to be a problem, How you branch off and in which order is down to how easy/difficult any layout is from a practical point of view, Sometimes cable lengths and volt drop considerations come into play but in this example extremely unlikely. You might want to consider whether it makes it easy/difficult for the next person after you to alter/amend/test it, or you might not.. price of cable might also be a consideration to some folk. Whether or not you might want to add an emergency light onto it might be another consideration.

 

[Adam_151]

Theres nothing wrong with your desired layout, the only issue you are likely to have is that don't think many downlights will accept 3 twins very easily, so chances are you'll need to use some kind of joint box, in which case, you should locate it at that downlight position so its easy to get to in future, rather than somewhere unknown part way along the run. You'd be better off with a J501 which is designed to fit through a downlight hole, or even terminate the light using a click flow connector (https://www.cef.co.uk/catalogue/products/5155653-20a-230v-3-pin-flow-connector-blue ) which will accept 3 twins in the supply side (it is designed to do so, although a little tight and you probably just need to take a bit of time/care) TBH its not a bad thing to have the flow connectors on all fittings, but very few would go to the effort unless the fittings stuggled to accept 2 twins (and thankfully, most manufacturers have caught on these days and most of designed for 2)

 

[Murdochcat]

Key thing is to ensure every joint is readily accessible

 

[flameport]

1st one is correct
2nd is a waste of cable
3rd adds a pointless junction box where no junction box is required.