Electrolux oven trips RCD fuse after heating for 1 minute?

Electrolux double oven trips RCD fuse after heating for 1 minute. The element was changed last year and still looks like new (and it didn't blow the RCD when the element had gone, it just didn't heat up at all). Grill element went a long time ago but I don't use it so never changed it. Element connector wires in the back panel look fine, no burnt out wires. Run out of idea's and would welcome help.