Since I had a diagram spare which I had drawn for the fan I just installed, I though I might as well wiki it along with some variations for ways of wring fans in bathrooms etc.
(not proof read yet, so probably full of typos!)
You might want to add the circuit for a common fan switched from two rooms with dp switches.
Owain
What are the rules on isolation switches? Are they mandatory for new installations, modification of old ones, like for like fan replacement, etc?
Theo
Yes for new, and a sensible option (but not mandatory) for existing installs.
I'm not the world's greatest when it comes to understanding house wiring but I was interested in your wiring diagrams because we're going to have the fan in our new bathroom wired to work when the room light is on. (And run on after the light is switched off.)
It's a low voltage fan. How different would the wiring be for a low volatge fan?
(It's purely out of interest, as an electrician will be doing it.)
Essentially it would be the same, except there is an additional power supply unit between the mains and the fan. So the wiring as shown would connect to the PSU rather than the fan, then a separate cable connects the PSU to the fan. The PSU can be located outside of the room if you want.
And presumably the trigger wire (at mains voltage) wouldn't go past the PSU.
I was a bit confused because I had thought the wiring for the trigger was in the fan unit itself and couldn't understand the part the PSU outside the bathroom played. Thank you.
That's correct.
The PSU (or Transformer as they are often less than accurately called), will typically have three inputs in (L, N, and LS, and also sometimes three wires out carrying power and a trigger (or sometimes just two, where there are no smarts in the fan at all, the the PSU takes care of everything and just powers the fan when appropriate.
You might like to add something similar to the Wiki page!
Let us know when he has done it and do not forget to slag his work off:-)
Alan, I wouldn't slag off good work by a tradesman. What I don't want is to be taken for a ride and get left with poor workmanship or silly overcharging.
-----
Perhaps you don't want to hear about the truly absurd price my mother paid to a plumber last Monday for 15 minutes work (he was in the house for 20 minutes) to fit two tap inserts with lever handles in the kitchen?
I had no say because it's her money and her kitchen, and although she has dementia she insists she knows exactly what she's doing (which is obviously untrue to any observer). So I watched the rip-off in silence. To add insult to injury, she can't count money any longer so asked me to take the right amount of cash from her purse to pay the plumber. Sigh.
-----
Don't start me on the man who came round last Wednesday to quote for some work on the damp we have been getting in the chimney breast when it rains.
He measured the damp on the chimney breast indoors with his digital damp meter and it read 100% on the barely damp spot. That was interesting because the wall wasn't anything like as wet as it sometimes gets and I couldn't see how his Stanley meter would put a figure on that greater damp if it had to measure it.
More interesting still was the 0% damp reading (yes, zero) on a wall near the chimney. I wonder what scale or control he flipped to get that absurd reading. I asked him to repeat it because I thought the probes weren't touching the wall but he still got 0%. I would have expect at least 45% relative humidity which would be lower than what the room hygrometer was showing. I just nodded and pretended I was oh-so-very impressed as I watched his unfolding performance. Maybe he thought he was auditioning for RADA.
I won't go into all the details but the leak seems to be due to an incorrectly fitting vent fitted, for some reason, on top of a chimney capped with lead and which may have been dislodged by strong winds.
It was no surprise then that to fix the leak he would need a scaffolding tower and full platform around the chimney (which is on the side of the house and can be reached by a ladder) for about ?500. But first he would need a morning for two of them to take a look and size up what was involved and that would cost ?200.
I think he should stroll on.
I know enough about damp not to need advice from here in this case but I hope you're not suggesting I shouldn't ask questions about what's involved in work when I don't understand it!
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.