I’m interested in the ELSDIN module (http://www.velleman.eu/products/view/?id=430166).
However I note that it has a limitation on the cable of 3m. Is there any way to increase this up to approx 20 or 30m?
I am afraid you can’t change the spec’s as in the manual. Depending on your application however you can always choose to put both parts as close as possible and use 20m of 240V lead.