Bathroom Extractor Fans and FCU's

[riveralt]

The other option would be to put the FCU directly in line with the lighting circuit - where it says neutral - live loop. The problem with this is that the way the lighting circuit is wired, if the fuse went then all the lights in three of the four downstairs rooms would go out as well.

Well don't do it that way then.

This is actually what the manufacturer instructions recommend.

 

[ban-all-sheds]

They recommend putting the entire part of the lighting circuit downstream from the fan on a 3A fuse?

I doubt it.

 

[riveralt]

They recommend putting the entire part of the lighting circuit downstream from the fan on a 3A fuse?

I doubt it.

I doubt that they meant to do that - less than a year ago they simply relied on the MCB and the three pole isolator for circuit protection. Now using the same schematic they have added the words 3Amp to the drawing.

Untitled

• riveralt
• 3 Dec 2010
• 1

 

[ban-all-sheds]

I doubt that they meant to do that

Not only did they not mean to, they didn't do.

The diagram you posted does not show the rest of the circuit on the 3A fuse.

 

[riveralt]

Come on BAS help me out here

I'm stuck with the red and black cables as they are:
I cannot run new cables to the switch:
If I interupt the live loop with one or both of the cables through a FCU the whole of the circuit relies on the 3Amp fuse:
If I replace the switch with a SFCU - I will lose the lights in the bathroom should the fuse fail:

Afterthought

I suppose the only other way would be to loop the live loop and neutral loop to the top of the FCU and then connect the other end of the live loop to the switch and permanent live on the fan and the other end of the neutral to the neutral on the fan. Then bring the switched live (protected) back up to the fan.

That way everything after the FCU will be protected by the 3amp - so the bathroom lights will be included but not the rest of the house.

 

[riveralt]

Extractor Fan 2 Version 2

• riveralt
• 4 Dec 2010
• 1

Done!

I know I have duplicated with the three pole isolator but that is what the MI say they want.

 

[ban-all-sheds]

Done!

There you go....

I know I have duplicated with the three pole isolator

No you haven't - as you neither replaced the light switch with a DP one nor introduced a contactor you need the 3P isolator to isolate the fan without also taking out the lights.