Do I need to change my hob/oven as it trips the fuse box?

Both issues are faults on the appliances themselves. The circuit breaker is tripping to clear the fault and make it safe. What you need to do is get an Appliance Electrician to look at the oven and hob and diagnose the faults and fit new replacement parts.

I would start at the beginning and first ascertain if the power feed to the appliance itself was actually adequate to deal with the demand of the said appliance. In addition and most importantly for your safety i would make sure you have fitted an RCD at the consumer unit if not already so that it switches off quickly should the fault occur again. I use a very low Milli amp Earth leakage tester for appliances and should also indicate very quickly there is a fault with appliance. Good luck and be Safe

Cofy86, Thank you for posting your "Q". In my view well experienced electrician would give indication as under rather than call for appliance engineer as they might not have insulation resistance and continuity tester!! There are few things can go wrong with your appliance. 1> If it’s too old internal wiring insulation resistance becoming poor (Deterioration) 2> If you recently cleaned this appliance and liquid may penetrate due to aging of the appliance and while you use it shorting at certain temp. 3> If short fault diagnostic carried out by your friendly, trust worthy electrician it will save you fortune before you invited big bill. 4> Check your appliance covers under supplier or manufactures warrantee or guarantee. You can always post your job on Mybuilder.com All the best.. Kind regards, OHM