A double pole switch is clasified as a single switch. It is NOT classified or approved to provide a switching means for 2 separate circuits being in conflicting voltage bands... And you can take that one to the bank!! lol!!
This is a lash-up mate, you need to talk to this so-called engineer face to face. As i said, i'd want a written instruction to connect a 230V line and a 24V line to the same switch, end of!! Even functional connections in the same accessory back box, isn't exactly in keeping with band segregation rules is it??
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