hi . connected cooker which had been unused for 4 years. keeps tripping fuse after about 30 to 40 seconds as its heating up. hob works fine only trips when oven and grill elements are on.
ah that’s ok then. you will find its an earth fault on the elements
try this
take the elements out ( don’t forget to make a note where the wires go. take them round to a friends house. put the elements in their oven at about 200 degrees for 30 mins to an hour
put them back and see what happens
if elements are not used they soak up moisture from the air. Heating them dries them out