Ground Floor Lighting Circuit Under Groundfloor Floorboards

[davas]

Basically... is the concept feasable?

The reason i ask is that i have a ground floor flat, hence no access to the ceiling space from above. So instead of hacking lots of lovley holes in the ceiling to run a new loop-in lighting ring I thought you could use junction boxes under the floor.

That would mean the power for the lighting running under the floorboards and then the switch cable runs up the wall to the switch in the same channel as the power to the lamp in the ceiling.

Does this sound daft or has it been done/seen in the past?

Anyone know of any compliance issues provided all cable run correctly in walls?

Thanks in advance

 

[baldelectrician]

If you have to ask this should you really be doing the work?

Try looping the mains through the switches below floor and taking one from each switch to each light

 

[davas]

this is what i was "theorising"...

 

[davas]

If you have to ask this should you really be doing the work?

Try looping the mains through the switches below floor and taking one from each switch to each light

sounds exactly like i saw it in my head (just didn't describe it well enough )

 

[baldelectrician]

lose the joint boxes

 

[andy]

run the cables around the top of the ceiling and cover with either trunking or coving. run cables down chased in walls. for lights, make a hole in ceiling at the end (coving will usually cover this) and a small hole at the light (light will often cover, but you might have to do some patching) and use a bit trunkin lid to fish the cables accross. much easier.

 

[davas]

run the cables around the top of the ceiling and cover with either trunking or coving. run cables down chased in walls. for lights, make a hole in ceiling at the end (coving will usually cover this) and a small hole at the light (light will often cover, but you might have to do some patching) and use a bit trunkin lid to fish the cables accross. much easier.

to be fair the ceiling will be getting skimmed anyway so this shouldn't be such a problem

 

[ban-all-sheds]

So instead of hacking lots of lovley holes in the ceiling to run a new loop-in lighting ring I thought you could use junction boxes under the floor.

1) Lighting circuits are not rings.

2) Why do you need a new circuit? What's wrong with the old one?

 

[davas]

So instead of hacking lots of lovley holes in the ceiling to run a new loop-in lighting ring I thought you could use junction boxes under the floor.

1) Lighting circuits are not rings.

2) Why do you need a new circuit? What's wrong with the old one?

I may be using the wrong terminology sorry

Old circuit is 1mm T+E, thought that i should upgrade to 1.5mm to allow more wattage. I calculated that at maximum I would be looking to connect 1.4kW to the lighting circuit. The TLC cable calculator then suggested using 1.5mm T+E.

I would prefer to use the current wiring (it is quite modern and is earthed etc) do you thing this is possible/safe?

 

[Lectrician]

 

[Lectrician]

Well, a 6amp MCB on 1mm cable will give you 1380watts - alot of work for 20watts

If I where you, I would split the circuit in thew middle somewhere - run a 1.0mm cable from a new mcb in the cu to the central part of the lighting circuit, creating two completely seperate circuits.

 

[davas]

Stop laughing at me!

Well, a 6amp MCB on 1mm cable will give you 1380watts - alot of work for 20watts

If I where you, I would split the circuit in thew middle somewhere - run a 1.0mm cable from a new mcb in the cu to the central part of the lighting circuit, creating two completely seperate circuits.

What is the equation for calculating the max wattage taking in account the cable size? 230 x 6 = 1380 or am i, again, barking up the wrong tree?

 

[andy]

What is the equation for calculating the max wattage taking in account the cable size? 230 x 6 = 1380 or am i, again, barking up the wrong tree?

yes, but 2 circuits gives you double power

 

[davas]

What is the equation for calculating the max wattage taking in account the cable size? 230 x 6 = 1380 or am i, again, barking up the wrong tree?

yes, but 2 circuits gives you double power

I realise that but i was wondering what the formula was out of interest.

I hadn't thought about splitting the lighting into two before now and i think it is definitely preferential at this point in time. It removes any fears I had (although they were probably unfounded) about the cable size and load etc.

Can anyone else see any issues with keeping the current wiring and splitting it into two circuits?

Thanks for your comments

 

[Lectrician]

I think it is 100% the way to go.

1mm (not 1.5) is fine for a 6amp load in most situations in a domestic property.