I'm fitting a couple of remote control ceiling windows. The ceiling is fairly high but the windows come with about a metre of flex with a plug on the end. It seems a bit much to fit a couple of sockets so high especially as they won't be reachable when completed. So my question is would it be unreasonable to extend the cables and wire into the lighting circuit. The instructions say to wire using 1.5mm t&e. Thanks in advance.
Although we do put some items onto lighting circuits the shaver socket is common the lighting circuits are limited to 6 amp as the ceiling rose is only rated at 6 amp and so anything taking more than 1/2 an amp will likely become a problem.
Also one has to consider maintenance and often service engineers want to remove the units service them then replace and if hard wired in that presents a problem.
Murphy's Law says anything mechanical will at some time break down and from bathroom fans one realises you must be able to isolate it should something go wrong and so if not plug and socket then needs an isolator anyway so no real advantage.
I would assume if 1.5mm then the current draw is too high for 1mm and 1mm is ratted at around 13A so seems likely too big anyway. One problem with any motor is inrush as they start so even if rated at 230W that does not mean 1A it could be 10A to start.
it may be, but as 1.5mm2 can carry up to 16Amps you would need to know the Amps/Watts of operator at full load.
If much more than 100W then should not be added to lighting circuit without investigating existing load,
40VA is a very low draw and should not be a problem on lighting circuit. You can consider VA as same as watts. With an AC current we can have power factor problems which is why the term VA is used rather than watts but in most cases it is the same as watts. It will draw about 0.2 of an amp. I would use some method of isolation so if it goes wrong you can switch it off. I would consider clock plugs and sockets would do nicely as then also fused to 1 amp. And easy to disconnect if required for maintenance. Another method would be Click ceiling roses. These have a plug and socket arrangement so you can disconnect lamps, very popular with florescent fittings so they can be removed for maintenance.
I have seen it a few times where a bathroom fan has failed and there is no isolator so the occupier is without lights until disconnected. So I would always fit some method to easy isolate and of course a plug and socket does that easy.
The Klik ceiling roses seem a good idea but due to the short length of flex it would mean either the roses will be hidden behind the ceiling plaster boards which obviously is a no go or look a tad unsightly on the underneath of the ceiling. Is it possible to extend the flex and run it to a fcu or are there other factors involved. This room is having it's own new 4mm radial circuit run from the fuseboard so would be a good opportunity to add a couple of fcu's.
To answer I would need to look at the job. I have extended flex using soldered joints and shrink sleeve but of course the joint will not flex and the joint can be seen.
As to sinking sockets into plaster board that depends on skill of person doing the job.
Plaster board backing boxes never seem to look as good as boxes screwed to noggins but are much easier to fit. Not seen square Klick ceiling roses but 5A or 2A round pin sockets or clock outlets will mount in standard plaster board backing box.
Since method used will depend on your own skill I can't really offer much more advice.