2 x 2Kw heaters on 13a spur

cornburn · Nov 8, 2011

I have 2 heaters on a 16a radial, but they are running through a 13a fused timer spur. Total measured current drawn is 16.5a, but the timer hasn't popped the fuse so far. Heaters are run for around an hour at a time, my thoughts are that the timer must have a tolerance for a couple of amps over it's official rating, so as all the cabling etc is well within spec might as well carry on using them. Does anyone know how long a 13a fuse should run with 16a going through it?

Cheers

telectrix · Nov 8, 2011

a fuse will generally withstand 1.45 x rated current for an hour.

GaryM · Nov 8, 2011

I've got an old Bussmann BS1362 spec sheet here and it lists 1.6In as 30 minutes minimum and 1.9In as 30 minutes maximum.

cornburn · Nov 9, 2011

Great, cheers - so for an hour at a time although not ideal it should be fine, as that's only 1.27xIn (plus they'll tick off and on it that time on thermostats so not on solidly). If they've fitted a 13a fuse to it they must have made sure the electronics inside can cope with extra current until the fuse pops, otherwise it wouldn't be much use would it!