using garage roller shutter lighting output on a 2-way light circuit, relay?

[pbarrett]

bit of dilemmna with a customer.

hes had a roller shutter garage door fitted, it has a 40w output for lighting. the thing is the garage has x4 5ft single fluros fitted on 2 way switcing from house door and near garage door (largish garage). he wants to the lights to be functioning from the roller shutter output, for the life of me i just cant come up with a solution which allows the lights to still function even when the dooors are not in operation. any ideas? or am just not thinking hard enough.

 

[vernam616]

Maybe take a cable from the output into the first fitting? thus when opening the door the lights will illuminate, and even when the garage is shut and left, you can always switch it too, only problem then is that it will send a live back to the door output

Oh and if this will work, the output will require a switched isolator

Thinking a little further, the supply to open the door will have to be on the garage lighting circuit

 

[HandySparks]

If I've understood correctly, you need a SPST (single pole single throw) 230V relay. Connect the coil to the lighting output from the door. Connect the contact across the 2-way 'strappers', ie between L1 and L2 on one of the switches or, if easier, between Com on one switch and Com on the other. This will turn the light on when door is opened and have no effect on the existing circuit when the relay is not energised.
If properly selected and installed, the relay will provide isolation between the two circuits. Mount the relay in a suitable box and put a lable on "Warning, two sources of supply" or similar.

 

[Knobhead]

That would do it very well.