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]

The simple answer is that all joints should be accessible .....

 

[Les Macaulay]

The simple answer is that all joints should be accessible .....

Thanks, Murdoch. Why did they get away with inaccessible joints. Is it the electrical Foreman to blame or what, speaking generally. I mean I've done this myself but never without a drawing and an indication of the removable floor hatch.

 

[Octopus]

The problem was, and stil is, the lack of definition of accessible.....

 

[westward10]

Can you post a pic of the "Octopus " box.

 

[Taylortwocities]

Back in the "old" days there was no appreciation of what happens to s screwed terminal joint. And no appreciation of just how long an installation can exist.

Nowadays we often work on installations that are decades old, and finding that Missing neutral connection in a buried terminal In a landing under a carpeted floor is a right PITA.

That's why, in hindsight, we have the requirement for all screwed terminations to be accessible.

In a few decades time, the Gods in IET may discover that the much lauded cure-all MF terminal has some shortcomings. But for now that's the regs we've got.

 

[davesparks]

Thanks, Murdoch. Why did they get away with inaccessible joints. Is it the electrical Foreman to blame or what, speaking generally. I mean I've done this myself but never without a drawing and an indication of the removable floor hatch.

Well for a start the regulations were quite different 40 years ago to what they are now.

 

[telectrix]

Well for a start the regulations were quite different 40 years ago to what they are now.

true. more common sense then, assuming that installations were carried out by competent sparks, now regulations get changed to allow for idiots.

 

[7029 dave]

3plate is still used, or LN looped in at the switch box.(god where is eng54 lol)

 

[snowhead]

Also thirty plus years ago no-one knew that chipboard flooring and for whatever reason, Laminate flooring over the top would become so popular.

Previously it wasn't so difficult to find a junction box by lifting a carpet to see where the tongue and grooved floor boards had been lifted.

 

[7029 dave]

Also thirty plus years ago no-one knew that chipboard flooring and for whatever reason, Laminate flooring over the top would become so popular.

Previously it wasn't so difficult to find a junction box by lifting a carpet to see where the tongue and grooved floor boards had been lifted.

I used to mark the boards JB

 

[Gavin John Hyde]

When doing a new light circuit. i worship the WAGO gods with my nice WAGO connectors and MF enclosures. saves ----ing around with fiddly screws. Thus far the light gods do not seem to be unhappy.

I always try and have the enclosure next to a joist or beam where a floorboard ends so that its readily accessible in future. with a lot of the new ones there are little clips on back that attach to screws to hold in situ.

 

[westward10]

Why do we need all these joint boxes on new lighting circuits.

 

[Octopus]

^^ if you are doing a new lighting circuit, why do you need ANY form of JB?

Edit: Poor design and install IMHO

 

[7029 dave]

^^ if you are doing a new lighting circuit, why do you need ANY form of JB?

Edit: Poor design and install IMHO

You don't need any joints especially on new builds.

 

[Octopus]

You don't need any joints especially on new builds.

I did say that..

 

[westward10]

I could understand it on the old two plate system years ago where circular junction boxes made the loop in/out/switching point but not in this day and age. As Murdoch says, poor design.

 

[7029 dave]

I did say that..

I KNOW , just backing up what you said.

 

[Hardwired]

Don't thing i've saw anyone install anything other than loop in at switch in the past ten years or so. Anything else is just a pain in the hoop.

 

[Les Macaulay]

I KNOW , just backing up what you said.

Thanks, guys, for all your replies.
Not one of you has said anything that I don't agree with. We often do things without thinking why. I try to think of myself or A.N.Other, coming back to the installation for maintenance, or replacement.

 

[Ian1981]

You need joint boxes when lights have been wired with the mains in out to the rose which can be standard in a new build when the house is not sold and it's basic spec.
Nothing wrong with this but say you then wanted to install downlights then joint boxes will be necessary.

 

[Les Macaulay]

You need joint boxes when lights have been wired with the mains in out to the rose which can be standard in a new build when the house is not sold and it's basic spec.
Nothing wrong with this but say you then wanted to install downlights then joint boxes will be necessary.

Alternatively if we all in future use the switch boxes as the joint box, then no joint boxes are necessary, even with down-lighters. The point is, joint boxes, if unable to be left easily accessible, then don't use them at all. The switch box method also makes inspection and testing easier and much quicker without going below floors or into attic spaces.

 

[Ian1981]

Alternatively if we all in future use the switch boxes as the joint box, then no joint boxes are necessary, even with down-lighters. The point is, joint boxes, if unable to be left easily accessible, then don't use them at all. The switch box method also makes inspection and testing easier and much quicker without going below floors or into attic spaces.

Can make things difficult to tap off a supply for another lighting point such as adding a light in a loft.
A harder task when all mains are located in the switch.
You maybe able to fish a cable down the wall depends really.

As said already if designing for downlights mains to the switch, if not there's no reason why you can't loop in out at the light.
No wrong way really.
Also one of our apprentices said the preferred way teaching at College is mains in out at the switch as it eliminates time spent 2nd fixing a light on steps which anything working off the ground is considered working at a height, eliminating accidents.

 

[Octopus]

You need joint boxes when lights have been wired with the mains in out to the rose which can be standard in a new build when the house is not sold and it's basic spec.
Nothing wrong with this but say you then wanted to install downlights then joint boxes will be necessary.

I disagree. Why do you need joint boxes, especially hidden ones the op is going on about.

Neural at switch is the way I normally go these days.....

 

[Les Macaulay]

Can make things difficult to tap off a supply for another lighting point such as adding a light in a loft.
A harder task when all mains are located in the switch.
You maybe able to fish a cable down the wall depends really.

As said already if designing for downlights mains to the switch, if not there's no reason why you can't loop in out at the light.
No wrong way really.
Also one of our apprentices said the preferred way teaching at College is mains in out at the switch as it eliminates time spent 2nd fixing a light on steps which anything working off the ground is considered working at a height, eliminating accidents.

 

[Les Macaulay]

You are right, Ian.
Was thinking of the type of terrace house where the octopus system has been used with the large joing box below the upstairs floor and client has composite flooring fitted. This would be a nighmare to gain access to the joint box. As you say, there is no right way.

 

[davesparks]

^^ if you are doing a new lighting circuit, why do you need ANY form of JB?

Edit: Poor design and install IMHO

I guess I'm guilty of poor design and install then!
When it's possible to locate it sensibly I always use a central RB4 type joint box for a lighting circuit.

 

[Octopus]

When it's possible to locate it sensibly I always use a central RB4 type joint box for a lighting circuit.

Best you define "sensibly" as I can't find that in the BYB!

 

[davesparks]

Best you define "sensibly" as I can't find that in the BYB!

Indeed, it's based entirely on my own opinion, and where I would be inclined to look for it.

So if in a loft I would mount it above insulation level, on a purlin or a board screwed to the uprights of trusses.
In a chalet bungalow it would be just inside the access into the eaves, again mounted above insulation level.
And if possible I will have a light fitting near it which is fed via a different circuit.

 

[Sollyg]

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

 

[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.