Domestic Lighting Circuit Methods In New Builds

[Les Macaulay]

To my knowledge, there are 3 methods of splitting the line conductor in each lighting circuit:

Joint box below floor, or above ceiling
Three terminal ceiling rose/batten lampholder
Joint in switch box (neutral)

I am wondering which method is most commonly used in new houses.

I have been in this house for nearly forty years and after upgrading the central heating from warm air to combi-boiler, the Scottish Gas Company's installers connected three smoke detectors to an octopus joint box.
After several years the downstairs lighting occasionally fails. After a time these lights begin to work again.

Being a retired spark, I checked all connections in the CU and they were all secure.

Not knowing where the octopus joint box for the entire four apartment house was located I lifted the fitted carpet upstairs landing and found it.

The line connection had approximately six conductors below a brass plate, but the added line conductor had caused the plate to ride on the additional conductor which was at an angle across the other six. Since the brass connection plate (about one inch long and secured at its centre by a single 2BA or 4mm brass screw had failed to put equal pressure on all conductors, time had caused it to develop an intermittent o/c of the line conductor feeding all downstairs lighting.

Summing up don't you think ALL future new builds should not use the octopus joint box system especially where it is sited below wooden floors with no removable hatch left for access nor even an indication of the position of same.

 

[Octopus]

Yes, unless you go to work on a horse

 

[davesparks]

Hi please can somebody help answer my question
I got a total of 50 spot lights in a house i am goin to install. I am goin to use wagos
Do I HAVE to put every light wagos connectors in an enclosure if so why?
Some body said just put insulation tape on them
All this is happening in terraced house with no insulation in ceiling and the lights are double insulated , all gonna b with led 4 watt bulb
Thank u

Yes'm every connection will need to be in an enclosure, the reason is that this is what is required by the regulations.

 

[Taylortwocities]

Hi please can somebody help answer my question

If you need to ask then you shouldn't be doing the job!
As above.
All terminations must be in an enclosure.
All cable sheaths must also enter the enclosure.
Unless the enclosure is screwed to a background,and the cables are clipped, then the enclosure must have strain relief for the cables.
If the termination is a screwed it must be accessible, or use a maintenance free termination.
There's probably more too.

Best to buy 50 Wagolight boxes to go with your downlights.

 

[Les Macaulay]

Yes'm every connection will need to be in an enclosure, the reason is that this is what is required by the regulations.

All joking apart, and based on practicalities, as what happened to me was my downstairs lights all failed one night. I checked all connections at the Consumer Unit and found them all to be tight. I removed two wall switches and saw that there must be a joint box or three terminal ceiling roses used but there were no three terminal ceiling roses in the installation. So where are the joints? Wiring was from the upstairs down to the ground floor switches, so the joint box/boxes had to be below the upstairs floor boards. I lifted the fitted carpet at one end of the long landing and found no sign of floor boards that had been marked to indicated where the joint box/boxes were. At last, I discovered the Octopus joint box system had been used. So all switch cables and ceiling point cables terminated in that box. It was, in effect a "Marshalling" box.
Upon opening the box I saw that the Gas Board electrician who installed the mains connected smoke detectors during the upgrade of the heating system from warm air to combi-boiler had connected his live feed under the connecting brass plate that joined all the switch feeds and the main feed for the circuit. But he had placed the copper at an angle over the existing coppers. The plate that clamped the six copper feeds was not making an effective pressure on all the coppers as a result. I assume that the coppers were seated in grooves in the octopus joint box. I tried to unscrew the brass 2BA or 4mm terminal screw but it was solid and it gave up till the next time. Since then the downstairs lights have never even flickered but I will go back and strip out the octopus box and use some other type of multi connecting method. I am trying to decide which method to use - terminal strips linked out, Wago's, solder the bloody coppers or whatever. Ideas please.
I give you all of this detail so that you will realise that joint boxes below wooden floors as a method of splitting the line conductor is very bad practice.
Suggestions welcome. Not prepared to move home!

 

[davesparks]

All joking apart, and based on practicalities, as what happened to me was my downstairs lights all failed one night. I checked all connections at the Consumer Unit and found them all to be tight. I removed two wall switches and saw that there must be a joint box or three terminal ceiling roses used but there were no three terminal ceiling roses in the installation. So where are the joints? Wiring was from the upstairs down to the ground floor switches, so the joint box/boxes had to be below the upstairs floor boards. I lifted the fitted carpet at one end of the long landing and found no sign of floor boards that had been marked to indicated where the joint box/boxes were. At last, I discovered the Octopus joint box system had been used. So all switch cables and ceiling point cables terminated in that box. It was, in effect a "Marshalling" box.
Upon opening the box I saw that the Gas Board electrician who installed the mains connected smoke detectors during the upgrade of the heating system from warm air to combi-boiler had connected his live feed under the connecting brass plate that joined all the switch feeds and the main feed for the circuit. But he had placed the copper at an angle over the existing coppers. The plate that clamped the six copper feeds was not making an effective pressure on all the coppers as a result. I assume that the coppers were seated in grooves in the octopus joint box. I tried to unscrew the brass 2BA or 4mm terminal screw but it was solid and it gave up till the next time. Since then the downstairs lights have never even flickered but I will go back and strip out the octopus box and use some other type of multi connecting method. I am trying to decide which method to use - terminal strips linked out, Wago's, solder the bloody coppers or whatever. Ideas please.
I give you all of this detail so that you will realise that joint boxes below wooden floors as a method of splitting the line conductor is very bad practice.
Suggestions welcome. Not prepared to move home!

I have not suggested that joint boxes below wooden floors, or in any inaccessible location, is a good thing.

Also as far as I can see from your story the fault has been caused by the gas installer and so you should be pursuing them to rectify the fault.

 

[Les Macaulay]

The thing is, it has taken more than six years to show so forget that. If it had. Een a mere month or two ago, I would have got the fitter back. Even the system installers were subbies of the Brittish Gas.
I will repair the fault myself but am only showing what can happen in the life of an installation, for the younger age group of sparks out there.
Thanks to all who have posted.