We've had the same problem for a few years now. Modern comsumer unit,
the trip would go about 1 in 3 times the iron was used. Nothing else
seems to throw the trip apart from the iron. I consider the iron to be
at fault. I've asked the ironong person to use it without any water
and the trip stays on. I can only assume that a faulty seal or
something similar has caused water to short the internal wiring. The
ironing person is apparently not happy at having to manually spray
water on the ironing but if it saves me having to go all the way down
to the garage to reset the RCD it has to be worth it.

Rgds

Noel

I trust that the 'ironing person' you refer to is your better half and you
don't employ any servants. Why bother with ironing anyway. I never do any.
Polyester/cotton shirts are just fine when tumble dried and why bother
ironing your undies/socks. I must admit however that I do like a nice
crisp, freshly ironed folded hankie :-)

Terry D.