I am fitting an extractor fan, with an led light and vented with an inline fan that dumps through the soffit. It requires a circuit breaker with a 3mm gap. My question is: does this relate to the RCD in the consumer unit or its it simply meaning that it needs to be connected via a switched spur with the switch having a 3mm gap? If the latter, can anyone recommend such a switch as I don't remember seeing measurements like this on the spurs I have used previously. I was intending to take the power for the fan from the same circuit as the shower itself, but before the shower isolation switch. I really appreciate any advice that can be offered.
Shower room extractor fan
- Thread starter greenhout
- Start date
Sponsored Links
Assuming you have a power (instant heat) shower (with a thick cable from the consumer unit) you cannot take power from this supply.
The usual place to power a fan is from the lighting circuit with a fan isolator switch.
If you are powering from a socket circuit then a standard switched FCU complies with the 3mm gap requirement.
The usual place to power a fan is from the lighting circuit with a fan isolator switch.
If you are powering from a socket circuit then a standard switched FCU complies with the 3mm gap requirement.
Thanks, I will take a spur off the ring main instead.
Sponsored Links
3mm gap relates to the contact gaps on the isolation switch.
The normal procedure as stated above by Taylortwocities, is to have a fan isolation switch (which is three pole) or a Switched fuse connection or even a two pole isolator. The configuration of the circuit, cable required and isolator to be best used would depend on whether you intend the ex-fan to work with any other lights within the location or just the shower light,
and where the power source is taken from.
As as the impeller and transformer are installed outside this location, any joints or terminations made in the electrical cable or components to it, will require to be easily accessible.
There will be a requirement to have the circuit 30mA RCD protected and any cable routes buried in walls will require to be within the permitted safe zones or mechanically protected.
There are also building regs concerning depth of wall chases and holing of joists, that need to be complied to.
The normal procedure as stated above by Taylortwocities, is to have a fan isolation switch (which is three pole) or a Switched fuse connection or even a two pole isolator. The configuration of the circuit, cable required and isolator to be best used would depend on whether you intend the ex-fan to work with any other lights within the location or just the shower light,
and where the power source is taken from.
As as the impeller and transformer are installed outside this location, any joints or terminations made in the electrical cable or components to it, will require to be easily accessible.
There will be a requirement to have the circuit 30mA RCD protected and any cable routes buried in walls will require to be within the permitted safe zones or mechanically protected.
There are also building regs concerning depth of wall chases and holing of joists, that need to be complied to.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
