My B and D D808 electric lawn mower -it's very old-cut out today as it has done many times before. Usually I can reset it by pressing a button and it's fine. Not today. Nothing would make it work. I changed the fuse in the plug on the extension cable which belongs to the mower, - a 3 amp fuse, three times and each time it cut out after a few seconds, so I assumed the problem was fuse related. Before giving up, I checked the plug and noticed the plug says 13 amps, but the appliance plate says 525 watts 240 volts 2-3 A -I assume the A means amps. I tried the 13 amp fuse in the plug anyway and it worked without cutting out. Then I read on the net that this is dangerous so why hasn't it blown? Why haven't I blown myself up-perish the thought.What do you think?
Monica

Monica, April 2010

The 13 A on a UK plug means that the plug is rated to carry a max of 13 amps. The largest fuse which can be used in this type of plug is 13 amp. A 13 amp fuse doesn't blow at 13 amp. This is the current it will carry without blowing. Once the current exceeds 13 amp, the fuse will eventually blow. The greater the current exceeds 13 amp, the quicker it will blow.
Lower powered appliances use lighter gauge flexes and the appliance itself may incorporate thinner wire. For this reason a lower rating fuse is used in the plug even though the plug has a 13a rating.
It is always dangerous to replace a fuse with a type which has a higher rating. The fuse is there to protect cable and appliance in the event of a fault and is the "weak link" in the chain, preventing a potential fire.
If a fuse keeps blowing, there is likely to be a fault in the mower. Possibly something is producing excess friction in the motor and this is causing a surge on startup which blows the fuse.

Euge, January 2013

Thanks Steve
I bought some new 3 amp fuses today , fitted one and the mower operates for two seconds then cuts out. I then tried a 5 amp-thinking safer than the 13 amp- and that worked for longer without cutting out -is that safe enough? ( I might add I am not actually mowing when I test , just pressing the handle!) If not I think I may just buy a new mower-this one is ancient so perhaps too old for any repairs and even if it could be , probably more expensive than new.
Monica.

Monica, April 2010

to work out the amps the device uses the basic calculation is watts divided by volts. Therefore your mower uses 2.1875 amps. A 3 amp fuse should be fine using that calculation. Sometimes motors use more just as they start up but i imagine the rating on the plate includes that as it will be the max wattage.

You should always use a fuse just over the appliance rating and a 13 amp one is well over so your're risking electrocution as the device has a fault.

I'd get it serviced.

Steve P, April 2010