Replacing a Bathroom Extractor Fan
- Thread starter leevis
- Start date
If it is 3C+earth, are all three cores (not counting the earth) connected to the existing fan? If so, that suggests that it probably is a timer fan, and that the cable would therefore probably be OK for a new timer fan.BuggerLooking at the cable that goes into the fan, its three core and earth (I think that's what its called - only one cable) is this more than a connection issue or will I need to totally re-cable the new one?
However, you seem to have implied that the existing fan went off immediately the light is turned off - is that the case? (I suppose it could be a timer fan with the run-on period turned right down to zero, OR it may have been mis-wired {L and S/L reversed), so that it has never functioned as a timer fan).
Kind Regards, John
You are right, fan only operated on with light on and off when light off. So I guess that the cable maybe 2C and not 3C, proof in the pudding will be when I disconnect it and take a look. Little bit confused now to be honest, but I think that what I need (apart from an electrician) would be to ensure that the cable going from the junction box (or wherever) to the new fan would be 3C & Earth, if it is twin (2C) then I will need to pull out and replace.
Because I thought that's what it was, sorry. this is all theory at the moment, haven't had a chance to get the fan off to have a look. Just trying to work out in my head where everything is going to go.
I know that these need either an isolating switch outside of the bathroom or a pull chord inside. Whats the preference on these? right outside there if a switch for the upstairs hall light switch so would prefer to keep these inside. I was planning on having a pull chord by the door so that when you enter you can pull it to get light and then maybe having an isolating pull switch next to the fan itself? Is this a good idea? What do most other people do in bathrooms these days?
I know that these need either an isolating switch outside of the bathroom or a pull chord inside. Whats the preference on these? right outside there if a switch for the upstairs hall light switch so would prefer to keep these inside. I was planning on having a pull chord by the door so that when you enter you can pull it to get light and then maybe having an isolating pull switch next to the fan itself? Is this a good idea? What do most other people do in bathrooms these days?
It's certainly true that you could not get the timer function of a fan to work with 2C+E (although it could be wired to work as a non-timer one). However, even if it's 3C+E, whether it would work (without modification) would depend on what the three cores are connected to at the other end (at a "JB or wherever").
Kind Regards, John
OK I think that I almost have a diagram as to how to do this but I am not sure if my set up as to what I want it to actually do is correct.
What I want it to do is to be permanently on and not in anyway affected by the light switch. As it has a humidistat, once set up correctly, it will just come on when required (I hope). If it turns out that it goes on when its not required I will look at adjusting it OR switch it off using the isolator switch.
What I plan is to use 3C from the isolator switch to the fan, on the fan itself there are 3 connectors, Live, Neutral and Switched Live and I plan to connect the 2 Lives to the Live and Switched Live and the Neutral to the Neutral. On the switch side I will connect one Live to L1, the other to L2 and the Neutral, same on the outside with the earth connected to the back box. This is using 3C from the junction box to the in's of this isolating switch.
Does this sound correct? The fan itself has a light built in to indicate on (not sure if this is a permanent feed on light on whether its a fan working light.
What I want it to do is to be permanently on and not in anyway affected by the light switch. As it has a humidistat, once set up correctly, it will just come on when required (I hope). If it turns out that it goes on when its not required I will look at adjusting it OR switch it off using the isolator switch.
What I plan is to use 3C from the isolator switch to the fan, on the fan itself there are 3 connectors, Live, Neutral and Switched Live and I plan to connect the 2 Lives to the Live and Switched Live and the Neutral to the Neutral. On the switch side I will connect one Live to L1, the other to L2 and the Neutral, same on the outside with the earth connected to the back box. This is using 3C from the junction box to the in's of this isolating switch.
Does this sound correct? The fan itself has a light built in to indicate on (not sure if this is a permanent feed on light on whether its a fan working light.
Can you clarify what you mean by that, in particular in relation to what the Neutral would be connected to?
Kind Regards, John
What I mean to say on this is on the fan isolator switch there are three inputs, L1 L2 and Neutral, with the 3C I was thinking about connecting as follows
L1 - Brown (L)
L2 - Grey (L)
N - Black (N)
Is that totally wrong? I thought it was right but reading back previously it may have implied that i was going to to put the second live in with the neutral, not my intention
L1 - Brown (L)
L2 - Grey (L)
N - Black (N)
Is that totally wrong? I thought it was right but reading back previously it may have implied that i was going to to put the second live in with the neutral, not my intention
You may use the colours any way you like, as long as you sleeve them appropriately at the terminals, but the use of black in a harmonised cable for neutral is deprecated, in an attempt to break the black/neutral association.
No - but see BAS's comments. Do you know for sure that the brown/black/grey conductors have the functions you indicate, and if so, are you sure you know which of brown and grey is the permanent live and which is the switched live? As BAS says, use of black for neutral is discouraged, but it is nevertheless compliant with regs, so long as it is over-sleeved with blue. The grey (assuming it is what you believe it to be) would also, strictly speaking, need to be over-sleeved, with brown.
Yes, it was rather unclear/ambiguous - which is why I asked you to clarify (and why BAS responded ... in a somewhat different way!).
Kind Regards, John
Yes, that is what is 'recommended' (with black over-sleeved with brown, and grey over-sleeved with blue). As BAS said, that is recommended because of an apparent desire to get the ('old-fashioned') idea of "black=neutral" out of people's heads!
Kind Regards, John
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