our cooker main oven stopped working about 3 weeks ago and we have been using the top oven until last night. every time we switch the cooker oven or ring on it trips the fuse circuits protected by RCD fuse. which also trips when we press the test button. if we reset the fuse the power light comes on, on the cooker but as soon as you try to use it it goes. any ideas, is it a faulty appliance or is the fuse the problem. any thoughts appreciated.