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.