Best practice when looping at ceiling rose

[Jupiter01]

I've always preferred this approach as opposed to looping at the switch - but for one drawback: a lot of cables to squeeze into some lights!

On this instance, I have the following at the ceiling: live feed, switch, smoke detector, extractor fan.

Q. Can I and is it good practice to wire all of these into a maintenance free junction box and have a single cable for the light coming through the plasterboard? I am fitting a new ceiling as part of this project.

Thanks in advance.

 

[flameport]

It could be done, but is hardly good practice or recommended.
All connections should be accessible, and on a new install there is no reason for them not to be.

Other options are to do all of the connections at the switch (a deeper box will be required)
or for a room with an extractor, put the connections in the box behind the fan isolator.

Unclear why you are having an extractor fan and a smoke detector in the same location - those two things are entirely incompatible.

 

[Jupiter01]

Thanks. Smoke detector is going in a different room but getting power from bathroom light is convenient.

The only reason for a single cable coming through the ceiling is that I often find that light fittings don’t have much space for all this cabling.

 

[EFLImpudence]

On this instance, I have the following at the ceiling: live feed, switch, smoke detector, extractor fan.

Q. Can I and is it good practice to wire all of these into a maintenance free junction box and have a single cable for the light coming through the plasterboard? I am fitting a new ceiling as part of this project.

There is no need if using a rose.

Tip: You have four cables coming through the hole, sheaths just entering.
Pull all conductor straight down and not tangled.
Connect earth wires first as they all go to the same place.
Route the wires so that none crosses over or is on top of another and cut to length, connect and then push all up flat to the rose.
Next, do the same for the four lives routing where the earths did not go if possible.
Then the three neutrals.
Finally the switched live.

Similar to this from Flameport:

 

[JohnW2]

There is no need if using a rose....

Whilst I'm sure it's do-able, with appropriate care ...

Route the wires so that none crosses over or is on top of another ..

I'm not convinced that that would be literally achievable with the OP's four cables. Also, with 4 pairs of conductors (maybe 9 'live' conductors in total if the fan is a timer one with a 3C+E cable), two or three of the rose terminals would presumably have to accommodate two conductors - which may or may not be 'easy'.

I'm also assuming that the OP is correct in saying that there re only four cables - which implies that it is the last fitting in the circuit (or, at least, a branch of the circuit). If it had a 'feed out' cable (as in the pic you posted), there would be 5 cables in total, with 10 or 11 'live' conductors in total.

Kind Regards, John

 

[SUNRAY]

I've always preferred this approach as opposed to looping at the switch - but for one drawback: a lot of cables to squeeze into some lights!

On this instance, I have the following at the ceiling: live feed, switch, smoke detector, extractor fan.

Q. Can I and is it good practice to wire all of these into a maintenance free junction box and have a single cable for the light coming through the plasterboard? I am fitting a new ceiling as part of this project.

Thanks in advance.

4 cables not a problem, se this thread with 8 cables: https://www.diynot.com/diy/threads/help-needed-with-bathroom-light.188661/

 

[sparkwright]

I've always preferred this approach as opposed to looping at the switch - but for one drawback: a lot of cables to squeeze into some lights!

On this instance, I have the following at the ceiling: live feed, switch, smoke detector, extractor fan.

Q. Can I and is it good practice to wire all of these into a maintenance free junction box and have a single cable for the light coming through the plasterboard? I am fitting a new ceiling as part of this project.

Thanks in advance.

You are fine to use a maintenance free junction box - that's what there for.

In days of old it was normal to use junction boxes even on new installs - to save space at the switch or light, and also to save copper.

Nowadays we try to avoid junction boxes, especially on new work, because they are usually unnecessary, and people now prefer to loop at the switch.

The only problem with what you propose is in the future someone may want to inspect this joint - but the reality is no one will care as long as it works and is safe.

 

[RF Lighting]

Don’t come running to us when your joint fails and you have to ruin your ceiling to get to it.

 

[Jupiter01]

Did you have your hands flapping by your ears and tongue pushed out as you said that

 

[sparkwright]

Millions of houses have junction boxes hidden away, you MAY be able to situate it near a corner, so a floorboard above can be removed easily to access it, if you have floorboards.

But I wouldn't worry about if you do a good job with the jb. The Hager MF junction boxes are relatively berk proof.

 

[Jupiter01]

UPDATE - I opted for a ceiling light which had lots of space behind it for the cables. I then used the Wago connectors to wire it all together. Thanks again