Replacing fluorescent light with LED Batten light and adding 2 additional leds

Rake722 · 25 Oct 2025

Evening all.

I would be grateful for a little guidance.

In our garage we have in centrally mounted fluorescent light. It works off a conventional single gang light switch and it is fed from a 2 amp 4 terminal JB.

There are a pair of T&E feeding the JB.

What I would like to do is to replace the fluorescent with LED batten and add 2 additional led batten lights one on either side of the existing.

Tonight I replaced the fluorescent with the first of 3 led batten units successfully.

I would like to ask how best to connect the additional 2 led lights ?

I though about cutting in to the 2 wires from the mains feed in to the JB and adding another JB there and dropping a spur in to the other led bit something tells me it’s not going to work.

I’ve attached a pic of JB connected to the existing led unit

Thanks in advance

securespark · 25 Oct 2025

You need to feed any subsequent fittings from the same 3 terminals as the wires that feed the existing fitting.

But that JB is now a bit busy.

What is the overall layout like?

Eg, where is the switch and the JB in relation to the existing fitting and the two additional proposed fittings?

Also, the sheath of the cable that leaves the bottom of the JB needs to be inside the box and the cables clipped near to where they enter the box.

Rake722 · 26 Oct 2025

securespark said:
You need to feed any subsequent fittings from the same 3 terminals as the wires that feed the existing fitting.

But that JB is now a bit busy.

What is the overall layout like?

Eg, where is the switch and the JB in relation to the existing fitting and the two additional proposed fittings?

Also, the sheath of the cable that leaves the bottom of the JB needs to be inside the box and the cables clipped near to where they enter the box.

Thanks for the reply.

Ok the layout is as follows, entrance door with switch on wall to the left. The JB is half way along the garage roof beam approximately 4 to 4 1/2 m away from the switch.

One of the new proposed lights would be in between the switch and the sensor pre-existing light and the other light would be on the other side of the already existing light furthest away from the switch.

Yes, the existing junction box seems to be getting crowded. As a stab in the dark how about I install the second light closer to the switch and move the junction box to it and then loop the other two lights in from the first one?

petebuiltit · 26 Oct 2025

Is this a pure lighting circuit? The cable seems to be 2.5mm, although difficult to tell from the pic. It's it's just lighting you could replace with 1.5mm or even 1mm depending on the expected load.

securespark · 26 Oct 2025

There's always more than one way to skin a cat.

If the fittings allow, you could take cables from the existing one: one going one way towards the door for one of the additional fittings and another going the other way for the other.

But that assumes there is space to enter, run and connect the cables inside the existing fitting.

Or, if the two lighting feeds both run from the direction of the switch, I might reroute them into the switch pattress, and then take the switched feed up to the first fitting, then loop to the middle one, then to the end one.

You may need a deeper pattress to contain the extra cabling and connector. Unless your switch has a neutral terminal, in which case you won't need a connector for that.

This method effectively does away with the JB and means all the connections can be done at ground level.

The disadvantage of wiring it this way is that you don't have a permanent live feed at the ceiling position (should you want one for a smoke or heat detector).
If you do, just take a length of 3 core up from the switch, connecting the third core to the permanent live feed and use the switched live and neutral for the fittings.

Edited for clarity.

Rake722 · 26 Oct 2025

petebuiltit said:
Is this a pure lighting circuit? The cable seems to be 2.5mm, although difficult to tell from the pic. It's it's just lighting you could replace with 1.5mm or even 1mm depending on the expected load.

Yes it’s just lighting. At the very end of the run there is another junction box that connects to exterior security lights but no sockets on this at all.

Rake722 · 26 Oct 2025

securespark said:
There's always more than one way to skin a cat.

If the fittings allow, you could take cables from the existing one: one going one way towards the door for one of the additional fittings and another going the other way for the other.

But that assumes there is space to enter, run and connect the cables inside the existing fitting.

Or, if the two lighting feeds both run from the direction of the switch, I might reroute them into the switch pattress, and then take the switched feed up to the first fitting, then loop to the middle one, then to the end one.

You may need a deeper pattress to contain the extra cabling and connector. Unless your switch has a neutral terminal, in which case you won't need a connector for that.

This method effectively does away with the JB and means all the connections can be done at ground level.

The disadvantage of wiring it this way is that you don't have a permanent live feed at the ceiling position (should you want one for a smoke or heat detector).
If you do, just take a length of 3 core up from the switch, connecting the third core to the permanent live feed and use the switched live and neutral for the fittings.

Edited for clarity.

Thanks - just getting my head around your second option.

Ideally your first would be the best but as you say it depends if the JB can accommodate the wires.

Another idea I had but not sure how good it is, is the cut the 2 wires coming from the switch just where the light fitting closest to the switch would go, add a JB there and a feed to the light unit, the. Do the same with the single wire on the other side of the existing light - would that work ?

securespark · 26 Oct 2025

securespark · 26 Oct 2025

Rake722 said:
Thanks - just getting my head around your second option.

Ideally your first would be the best but as you say it depends if the JB can accommodate the wires.

No, you don't take the extra connections from the JB, but rather from the existing fitting, if it will allow.

This means you don't have to add any extra cables to the JB.

Rake722 said:
Another idea I had but not sure how good it is, is the cut the 2 wires coming from the switch just where the light fitting closest to the switch would go, add a JB there and a feed to the light unit, the.

If you only have one cable going to the switch (which I think from a look at your JB you do) then this will not work, as you don't have a neutral there.

Even if this were possible, why add a JB?

It would be better to take the feed to the light fitting straight into the switch box and avoid a JB altogether.

Rake722 said:
Do the same with the single wire on the other side of the existing light - would that work ?

If you can, take a cable from the existing fitting.

securespark · 26 Oct 2025

Post some pictures please, that would help enormously.

Pictures of the switch, the existing light fitting inside of it as well as the outside of it and the general view in the garage, please.

Rake722 · 26 Oct 2025

securespark said:
Post some pictures please, that would help enormously.

Pictures of the switch, the existing light fitting inside of it as well as the outside of it and the general view in the garage, please.

I will do that this afternoon. I agree pictures would help a bunch.

Rake722 · 26 Oct 2025

Rake722 said:
I will do that this afternoon. I agree pictures would help a bunch.

I ripped over to the house to get some pictures. The first is obviously the switch the switch wire goes up some conduit and comes out as a single wire. It’s a little bit difficult to see where it goes but it then becomes two wires and I must assume that the second wire is coming out of that circuit breaker. Both wires then run along the rafters. Please ignore the white junction box that was me having a go on my own. I cut the wires but then realised that it wasn’t going to work so pretend the junction box is not there. The two wires, then go to the junction box that was there before which is the brown junction box. The previous person left a tail disconnected. I assume the addition of a second light further to the back of the garage, this has been left hanging and then a single wire from the junction box goes along the rafter to the back of the garage where it meets another junction box which was used for security lighting outside.

I hope that clarifies things a little

Rake722 · 26 Oct 2025

Just an idea the middle light the existing one works correctly, inside the unit There is a connector that allows a total of six wires. I assume so you can loop another light unit off it. Could I not just connect a larger chocolate block connector inside the casing of the light connect and to the Unit input and then use the chocolate block to connect two additional wires and run them out to each light either side ?

Rake722 · 26 Oct 2025

All done. Chocolate block idea worked a treat.

Thanks for the help.

Now to add some sockets on a different circuit

securespark · 26 Oct 2025

Rake722 said:
Just an idea the middle light the existing one works correctly, inside the unit There is a connector that allows a total of six wires. I assume so you can loop another light unit off it. Could I not just connect a larger chocolate block connector inside the casing of the light connect and to the Unit input and then use the chocolate block to connect two additional wires and run them out to each light either side ?

Yes, that's what I was suggesting in the first part of post # 5.

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Replacing fluorescent light with LED Batten light and adding 2 additional leds

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