Plastic or metal Enclosure?

[Ian1972]

Hi, I've done some work in a house, I used an existing 10mm cable on a B40 MCB to supply a 2 way consumer unit to control a heat pump and immersion heater, I need to fit a Type F RCD for the inverter in the heat pump, I'm thinking I'll fit this at the consumer unit end so the 10mm has additional protection, I plan to mount this next to the consumer unit in a 2 way enclosure, Question is can this be a plastic enclosure or does it need to be metal?

Thanks in advance

 

[Dave OCD]

In my opinion if it's purely a 2 module enclosure for a RCD an insulated enclosure will be fine - but others may disagree.