I need to fuse a fan at 3A. I've got a ban against sinking further boxes unless absolutely required so I'd like to stick a 3 pole fan isolator outside the bathroom and put a 2 pole FCU in the loft.
1) Can I put the FCU in the loft, given I'm only using it for fusing, not isolation? 2) Can I fuse L and Switched L (simplifies my wiring) or do I need to fuse L and N. I can't see why I would have to, but just checking!TIA,
Ben
Do not put a fuse in the neutral line.
Both live and switched live should be fused but you only use one fuse.
I like the idea of having a switch of some kind for any item that is in a loft myself. Brian
Who knows what I was thinking when I wrote that. Obviously I need to fuse L before it feeds switched L, unless I am magically going to find an FCU that contains two fuses.
Thanks to those who replied.
Depending on how you wire it a 3A switched FCU could act as a fan isolator.
Mine is a SFCU wired to a pull switch, so only the CU needed for isolation. I turn on the fan, give it a few seconds to start up, turn it off and it runs for ~25 min. The pull switch is 2-way as, when I get a tuit, I've a little timer that I can rig in to get around me forgetting to turn off the fan. The timer can be wired to be self-de-energising.
Does an FCU have the required 3mm contact spacing?
NT
Just look for one to BS 1363-4 (as even the cheapest seem to be)? (Was in Table 53.2 in the 17th. I can't justify buying the 18th.)
That table mentions BS3676: Pt 1 1989, BS EN 60669-2-4 and BS EN 60947-3 as being compliant.
NT
Is that after amendment? In my original the entry in Table 53.2 for a
*SFCU* is that BS 1363-4 gets a tick for isolation. There's a copy of the table in Wiring Matters Spring 2009 page 14
Ah, seems I was looking in the wrong section, at switching devices. BS1363-4 it is. Bit surprised to see unswitched FCUs being acceptable too.
NT
Yes. It is purposed as an isolating device by design.
Having selected my fan (Soler & Pau Silent 100 CHZ 230V IP45) and installed it, I can find absolutely no mention in the manual of any fusing requirement! Might have got lucky here.
It's ONLY if the manufacturer says you have to...
True.
I have an S&P TD axial. I don't believe mine needs a 3A fuse - but the Manrose humidistat does(!!!) so I had to fuse it anyway.
But it will save me the bother in the shower room which will be conventionally coupled to the lighting...
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