Extraction fan switching on

[lumphammer]

I put in new lights and extraction fan in a new bathroom, taking mains feed from existing JB to a new JB for the 4 low voltage lights and centrifugal fan.

The customer is reporting that another extraction fan in an en-suite at the other end of the house intermittantly comes on when the new bathroom lights are used. I have repeated this once in about 20 attempts with various combinations of other lights on. I have checked the wiring and there is no link to the ensuite other than through the normal loop-in out mains feed. I haven't altered any of the wiring to the ensuite lights/ fan.

The en-suite fan comes on- the en-suite lights don't This appears to be some form of interference switching on the fan.

I would welcome any advice on correcting problem.

 

[bernardgreen]

The customer is reporting that another extraction fan in an en-suite at the other end of the house intermittantly comes on when the new bathroom lights are used.

This may be the high frequency electrical "noise" crossing via inter-wire capacitance from live to switched live for the fan in the en-suite and triggering the run on timer. At high frequency the capacitance will pass much more energy that at 50 Hz and this may be enough energy to raise the voltage on switched live high enough to trigger the timer.

Is the fan in the en-suite associated with a lamp and if so is that lamp a low energy type that could be replaced with a filament bulb for a test period. The filament will drain the energy from switched live to neutral.

If that works then a 270 K ohm (270,000 ohm ) 1 watt resistor between switched live and neutral at the fan should solve the problem.

 

[lumphammer]

Is the fan in the en-suite associated with a lamp and if so is that lamp a low energy type that could be replaced with a filament bulb for a test period. The filament will drain the energy from switched live to neutral.

If that works then a 270 K ohm (270,000 ohm ) 1 watt resistor between switched live and neutral at the fan should solve the problem.

The ensuite has 3 low voltage lights running off a single transformer.

I will try the resistor anyway.

Thanks