Bathroom extractor recommendations

[SparkyChick]

I think whether the 3A fuse blows before a 6A breaker trips depends on the characteristics of the fault. Under certain conditions the MCB will sit there quite happily while the fuse should melt.

There are some fans that don't require fusing down. I can't remember off the top of my head but it maybe Vent Axia... I'll know for certain soon as I've got a couple of bathroom fans to replace myself for existing clients, they aren't too well and I want to avoid the unecessary disruption of lots of tinkering so I'll be sourcing some

See, I just don't get that only fusing the permanent live, and the reason I say this is because ultimately the timer boards are electronic. You can't plan the failure mode of electronic components when they go up in smoke. I know the power is removed when the lights feeding the switched live is removed, but still. It just doesn't sit well with me, maybe I'm being too overly cautious about it.

 

[Marcus Vaughan]

I think whether the 3A fuse blows before a 6A breaker trips depends on the characteristics of the fault. Under certain conditions the MCB will sit there quite happily while the fuse should melt.

There are some fans that don't require fusing down. I can't remember off the top of my head but it maybe Vent Axia... I'll know for certain soon as I've got a couple of bathroom fans to replace myself for existing clients, they aren't too well and I want to avoid the unecessary disruption of lots of tinkering so I'll be sourcing some

See, I just don't get that only fusing the permanent live, and the reason I say this is because ultimately the timer boards are electronic. You can't plan the failure mode of electronic components when they go up in smoke. I know the power is removed when the lights feeding the switched live is removed, but still. It just doesn't sit well with me, maybe I'm being too overly cautious about it.

Better too cautious than not cautious enough.

I think I’m going to follow your lead...

 

[Baddegg]

Better too cautious than not cautious enough.

I think I’m going to follow your lead...

That’s always my preference but as SC says it’s not always practical to fuse down the whole bathroom,So it’s always nice to have the option of a manufacturer that doesn’t spec fusing down

 

[Baddegg]

I think whether the 3A fuse blows before a 6A breaker trips depends on the characteristics of the fault. Under certain conditions the MCB will sit there quite happily while the fuse should melt.

There are some fans that don't require fusing down. I can't remember off the top of my head but it maybe Vent Axia... I'll know for certain soon as I've got a couple of bathroom fans to replace myself for existing clients, they aren't too well and I want to avoid the unecessary disruption of lots of tinkering so I'll be sourcing some

See, I just don't get that only fusing the permanent live, and the reason I say this is because ultimately the timer boards are electronic. You can't plan the failure mode of electronic components when they go up in smoke. I know the power is removed when the lights feeding the switched live is removed, but still. It just doesn't sit well with me, maybe I'm being too overly cautious about it.

I think vortice don’t need fusing SC

 

[Octopus]

Greenwood and S&P don't need fuses ........................

 

[Jymbob]

See, I just don't get that only fusing the permanent live, and the reason I say this is because ultimately the timer boards are electronic. You can't plan the failure mode of electronic components when they go up in smoke. I know the power is removed when the lights feeding the switched live is removed, but still. It just doesn't sit well with me, maybe I'm being too overly cautious about it.

My limited understanding was that the fuse was there in case the fan gets installed and then forgotten about for 5 years, at which point the motor is trying to spin blades covered in ming and overheating. So more overcurrent failure than electronic in mind, but I can see your point.

My Xpelair Simply Silent is lovely and quiet, and it specified a 5A DP isolator before the light switch, so that's what it's got.

 

[garaoke]

Seems a bit of minefield this issue and there are lots of posts regarding it on this forum. Some say that a 6amp Type B MCB will trip before the 3amp BS1362 pops, though I don't believe that when looking at the time/current characteristics for both. I think the 3amp will blow at 5amp or soon after.

I'm no expert but trying to get my head round it all. It has been mentioned on here that the switch line operates the timer only and the permanent live feeds the fan. So if the fan starts sticking or drawing more current then perhaps only the permanent live needs fusing down.

See attached though, for the icon30, which shows you can, if using external switching, get away with the 3 amp fuse in the permanent live only.

So I know I have to pay particular to manufacturers instructions with fans.

All this aside, I like the way you overcome this, as it removes all doubt.

But what I would like to do even more, and going back to to the original post, is buy fans that do not need fusing down!

The answer is follow manufacturers recommendations as they overrule bs7671