It depends if the fan's instruction manual asked for it in the first place. Some do, some don't.
The lighting 6A breaker will trip well before a 3A fuse will blow anyway
The lighting 6A breaker will trip well before a 3A fuse will blow anyway
Other way round. For any given overcurrent, a 3A BS1362 fuse has a faster operating time than a 6A BS60898 breaker.
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The 3A fuse is actually for fire protection.
wow, that is what they recommend to prevent overheating due to a stalled motor?
or have I mis understood?
Indeed, the motor windings are far thinner than 3A fuse wire.
I do wonder what they do in the EU where they don't have 3A fuses as part of typical fixed wiring?
My only comment on this thread is that there was a fire in a new build near me, a few years ago, that originated in the bathroom fan. Stalled motor and no 3A fuse in the feed was reported to be the cause.
My suspicion is that is what the insurer's say to get out of paying.
What do they do in the EU where 3A fuses are practically unheard of?
How is the disconnection level of the fuse, say ~6A = 1.3kW, making a big difference to a fire in such a small area, and are there not thermal cutout to protect the motor, etc.
Yes, I know that the MI says "XYZ" ands we should be following it, but equally it would be interesting to see just what the theoretical modelling of a fault is that allows a 3A fuse to save the day but a 6A MCB is able to cause an inferno.
Doing an EICR, would you expect to see instruction manuals for such equipment, mostly installed years previously.
Was he the dog on Magic Roundabout?
In general I'd rather end up with a shorter list of EICR findings that are actually significant than a long list with some of them being more or less irrelevant.
If I code a missing 3A fuse for a fan it could lead to other findings that are much more important being taken less seriously.
If I code a missing 3A fuse for a fan it could lead to other findings that are much more important being taken less seriously.
Usually the Fan is connected to the lighting supply in a domestic situation & in the bathroom area.
Not seen a switched spur in those situations, which could be awkward to action.
Seems reasonable if required but like I said never seen it done, TBF don’t think I’ve ever coded it or even thought of coding, im looking for the isolation switch only… but may think differently now
Not seen a switched spur in those situations, which could be awkward to action.
Seems reasonable if required but like I said never seen it done, TBF don’t think I’ve ever coded it or even thought of coding, im looking for the isolation switch only… but may think differently now
How would you code it if there's no isolation switch? Don't remember a reg for that...
Yes, but that’s for stuff like lathes, not a bathroom fan.
Bathroom fans need regular maintenance to remove the build up of skin tissue from them, and there are live exposed terminals (often permanently live) while doing so.
Maybe a C3 we always fit a 3/4 Pole isolation switchHow would you code it if there's no isolation switch? Don't remember a reg for that...
I dont go maintaining/cleaning my fans at night time, so I (radical I know) wander over to the consumer unit and turn off the MCB for the circuit that powers the fan.
Which only isolates the line and not the neutral - apologies for lighting the blue touch paper as it were
Most fractional HP motors like bathroom fans are wound in such a way that the winding impedance is high enough to limit the current to safe levels even if the rotor is locked. They're often marked as 'impedance protected' which means the fault current won't rise high enough to cause a temperature rise that's hazardous or likely to cause a fire. This type of motor design usually won't have a thermal fuse on the windings because the normal running temp is pretty close to the locked rotor temp..
Designing a motor to be impedance protected is good practice and very effective but I'd guess that many nameless far East factories would be churning out motors of sloppy design that wouldn't perform this way in real life so I wouldn't have an issue with a local fuse for added protection. Add to this the fact that most are likely to be ClassII ⧈ with no CPC and therefore no effective RCD protection the hazard becomes increased. I do however wonder where they came up with 3 Amps as an appropriate value for a motor with an RLA/FLA of probably 0.1 - 0.2Amps .... I'd be erring on the side of caution with a 0.5 or 1 Amp fuse if it were my bathroom.
If the fan is connected to an RCD prorected circuit, then the RCD would still detect an unexpected path back to earth in the event of someone receving a shock, even if the fan itself is class II.
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