u/Prestigious_Sea6157

Hi - looking to trigger an automation from light on - but no neutral

More specifically I'm looking to trigger an automation to turn on hot water pump, when the bathroom light comes on.

The bathroom light (wired outside bathroom) is a dual switch, but the bathroom switch specifically does not have a neutral as i understand it (one live into COM, one cable out of L1, nothing in L2). There is a bunch of other wiring in the box, but unsure of its purpose.

All i need is a trigger from here (do not need to remotely trigger the light). Would like to avoid wiring into the light itself as are downlights and would be a pain to do

Could do it with a light/movement sensor in the bathroom but that seems like overengineering.. am i missing something obvious or an obvious alternative?

Have installed sigenergy + intelligent go tariff for EV. Using sig AI which is doing well - with the exception of handling the extra octopus intelligent slots

As i currently set the tariff plan in sigen manually, and there's no integration for this intelligent tariff, for the hours (2330-530 offpeak) any extra window put in by octopus will not register - meaning when the charger pulls electric then, the system will dump the battery to power it.

I've managed to get all the tariffs into home assistant, including when octopus adds new windows - however cant see how i can automate the writing of the new windows into the sigen app. Anyone dealt with this?