Posted By AL John, You want ohms law, watts/volt = amps AL

Posted By Alec Wood Every appliance has a rating label, or should have, showing the power consumption in watts (W) or in kilowatts (kW). One kilowatt = 1000 watts. Simply divide this figure by 240 to get an approximation of the current consumption of the unit in amps (A). Your fuse should be the closest ABOVE this value. Fuses for standard mains plugs come in 3,5 and 13A. There are other values available but these are the common ones. The instructions supplied with the appliance should be heeded in all cases, but if they are not available then; Appliance 600W or less use a 3A fuse Appliance 600-1000W use a 5A fuse Appliance over 1000W use a 13A fuse Fuses and their ratings are a complex issue but the above guide should suffice for most purposes. Remember the purpose of a fuse is to protect the cable from overload and the resulting fire, not to protect the appliance from damage. Fuses MUST always be replaced with the correct value to ensure the integrity of this protection and user safety. *****For those who have mistaken this forum for an episode of University Challenge, I know the mains voltage changed to 230V some time ago, but that figure is nominal and 240V is common and remains a reasonable approximation in this instance and for this purpose. Those who have mistaken the forum for an episode of Countdown may still pick my spelling to bits though - I appreciate the educational service you offer :-)

Posted By john martin Thanks thats a great help. some of the appliances don't hanve a wattage rating on them so i can't always find the fuse required.