Hi
I wanted to install an inline fan for the bathroom in the loft and was planning to do the electrical connection until learning while researching that this may not be allowed due to the involvement of the bathroom. I'm looking for guidance about the rules if I DIY, as it's not clear to me if it's allowable/notifiable etc. I'd still like to know what's involved so I understand what I'm asking from the electrician if that's needed.
My current set up has a wall mounted fan, in zone 1 connected via a 12v transformer from the lighting circuit. The feed-in and out and all the other wires connect at the isolator. The wiring from the isolator to the 12v transformer has a switched live (from the light pull) available but this is currently capped as the fan was replaced with an always on humidity controlled version. There's a decent gap under the door and the window has a trickle vent always open and the window is often ajar ("locked" open). This (top of the range) fan is still not powerful enough, and we have a condensation problem especially in the shoulder season. The light pull, fan isolator and transformer are all located IN the bathroom near each other, out of a zone and at ceiling height above the door.
The inline fan will be installed in the loft above the bathroom and I planned to simply take out the existing wiring between the isolator and transformer and clip a new 1mm 3c&E via the joists to the new fan location in the loft. I say simply. I was going to reconnect all the wires, using wagos in a wago box in the loft directly above their current location and take the isolator to near the loft hatch entrance (in the loft) via 3c&e which will be closer to the fan and more logical if maintenance required. Then remove the redundant transformer and fan, fill all the holes and make good the old fan hole in the wall.
At this point is it in "allowed" territory under replace and repair existing accessories? Is it notifiable? The fan itself is not in the bathroom, unfortunately there are electrical elements that are (but "shouldn't" be) but I'm not adding any new elements to what's already there, and arguably resolving an 'unsafe' situation with the non-IPx4 isolator and transformer being in the bathroom and hence making it better than it was.
My research then threw up that I need an RCD for the bathroom and the fan instructions called for 3A fuse. My CU has a single "upstairs lighting" MCB of which the bathroom is on the circuit, and the whole CU is protected by the built in RCD matching the required spec. When I test the RCD, the lights are off. Assuming the lights are served by the RCD does this cover the requirement? Our CU is aged and obviously any changes here would not only need a qualified person but probably replacing the whole thing since they no longer make the parts.
Regarding the fuse, some debate about the usefulness of 3A fuse on lighting circuit. I believe part P says you have to follow manufacturer's instructions. I bought a new face plate with a 3A fuse and 3 pole isolator combined. The wiring scheme for this complicates things because the fuse has to cover the light as well so instead of simply running a longer 3c cable to the isolation switch, to avoid altering all the wiring I'll now have to have another (2c+e) cable going back to the light switch containing the fused live (the other conductor will be not in use and capped either end). OR I suppose I could get a FCU and mount/wire that in appropriately near the wago box, using the 3c&e to the isolator as originally planned. But then we start introducing new components to the circuit. Any other options?
If all of this ends up as not allowed/notifiable, if I take power from the landing light 30cm away instead and fit a manual fan switch for the switched live outside the bathroom does this remove the issue, being that nothing then is actually in the bathroom or touching its electrics? Or if I forego the run-on timer and take power from the switched live connected to the bathroom light would that change anything (the light would be in zone 2 except it's on the ceiling at 2.3m)?
Many thanks in advance if you've read this far, it's a long one but I wanted to get as much info in the post as possible.
I wanted to install an inline fan for the bathroom in the loft and was planning to do the electrical connection until learning while researching that this may not be allowed due to the involvement of the bathroom. I'm looking for guidance about the rules if I DIY, as it's not clear to me if it's allowable/notifiable etc. I'd still like to know what's involved so I understand what I'm asking from the electrician if that's needed.
My current set up has a wall mounted fan, in zone 1 connected via a 12v transformer from the lighting circuit. The feed-in and out and all the other wires connect at the isolator. The wiring from the isolator to the 12v transformer has a switched live (from the light pull) available but this is currently capped as the fan was replaced with an always on humidity controlled version. There's a decent gap under the door and the window has a trickle vent always open and the window is often ajar ("locked" open). This (top of the range) fan is still not powerful enough, and we have a condensation problem especially in the shoulder season. The light pull, fan isolator and transformer are all located IN the bathroom near each other, out of a zone and at ceiling height above the door.
The inline fan will be installed in the loft above the bathroom and I planned to simply take out the existing wiring between the isolator and transformer and clip a new 1mm 3c&E via the joists to the new fan location in the loft. I say simply. I was going to reconnect all the wires, using wagos in a wago box in the loft directly above their current location and take the isolator to near the loft hatch entrance (in the loft) via 3c&e which will be closer to the fan and more logical if maintenance required. Then remove the redundant transformer and fan, fill all the holes and make good the old fan hole in the wall.
At this point is it in "allowed" territory under replace and repair existing accessories? Is it notifiable? The fan itself is not in the bathroom, unfortunately there are electrical elements that are (but "shouldn't" be) but I'm not adding any new elements to what's already there, and arguably resolving an 'unsafe' situation with the non-IPx4 isolator and transformer being in the bathroom and hence making it better than it was.
My research then threw up that I need an RCD for the bathroom and the fan instructions called for 3A fuse. My CU has a single "upstairs lighting" MCB of which the bathroom is on the circuit, and the whole CU is protected by the built in RCD matching the required spec. When I test the RCD, the lights are off. Assuming the lights are served by the RCD does this cover the requirement? Our CU is aged and obviously any changes here would not only need a qualified person but probably replacing the whole thing since they no longer make the parts.
Regarding the fuse, some debate about the usefulness of 3A fuse on lighting circuit. I believe part P says you have to follow manufacturer's instructions. I bought a new face plate with a 3A fuse and 3 pole isolator combined. The wiring scheme for this complicates things because the fuse has to cover the light as well so instead of simply running a longer 3c cable to the isolation switch, to avoid altering all the wiring I'll now have to have another (2c+e) cable going back to the light switch containing the fused live (the other conductor will be not in use and capped either end). OR I suppose I could get a FCU and mount/wire that in appropriately near the wago box, using the 3c&e to the isolator as originally planned. But then we start introducing new components to the circuit. Any other options?
If all of this ends up as not allowed/notifiable, if I take power from the landing light 30cm away instead and fit a manual fan switch for the switched live outside the bathroom does this remove the issue, being that nothing then is actually in the bathroom or touching its electrics? Or if I forego the run-on timer and take power from the switched live connected to the bathroom light would that change anything (the light would be in zone 2 except it's on the ceiling at 2.3m)?
Many thanks in advance if you've read this far, it's a long one but I wanted to get as much info in the post as possible.
