Overload

[Farmelectrics]

Question an under floor heating/ cooling box reading 17amp on my clamp meter but the supply is from a 13amp plug now I no a fuse or mcb can take 1 1/2 times its load for a certain time not sure for how long but my question is why hasn't this took the 13amp fuse out

 

[Leesparkykent]

I take it the underfloor heating is thermostatically controlled?

 

[Farmelectrics]

Yes lee it is

 

[Farmelectrics]

Set to 21 degree with a dead band of 2 degree

 

[Farmelectrics]

Strange it hasn't taken the 13amp fuse out

 

[Leesparkykent]

I think a 13amp bs1362 fuse is required to operate @ 1.9 x rated current (24.7 A) within 30 minutes, so all I can think is that the thermostat is cutting the load before this happens.

 

[Farmelectrics]

Yes I'm thinking along the same lines are you sure it's 1.9 times seems high that were did you get that value from

 

[Leesparkykent]

Yes I'm thinking along the same lines are you sure it's 1.9 times seems high that were did you get that value from

Not 100% but it's the figure I seem to recall.

 

[Farmelectrics]

Ok thanks lee sad this talking work Saturday night ha ha time to crack on with this crate of cobra lol

 

[Leesparkykent]

Ok thanks lee sad this talking work Saturday night ha ha time to crack on with this crate of cobra lol

I've been on it most of the afternoon, went for a pub lunch and carried on lol

 

[Farmelectrics]

Been the game you need a few beers watching my team

 

[HappyHippyDad]

Question an under floor heating/ cooling box reading 17amp on my clamp meter but the supply is from a 13amp plug now I no a fuse or mcb can take 1 1/2 times its load for a certain time not sure for how long but my question is why hasn't this took the 13amp fuse out

Have a look at the time/current characteristics (appendix 3 in BS7671). I cant find any tables for a BS1363 fuse that you are looking for but to put it in perspective a 15A BS3036 fuse will take 5 minutes to blow with 30A running through it and would take days of continuous use (probably weeks... if at all) to blow with 20A running through it, so I cant see 17A troubling a 13A fuse too much. At a guess I would say a week of continuous use at 17A might blow it, but a few hours a day probably wont touch it!

 

[Leesparkykent]

Have a look at the time/current characteristics (appendix 3 in BS7671). I cant find any tables for a BS1363 fuse that you are looking for but to put it in perspective a 15A BS3036 fuse will take 5 minutes to blow with 30A running through it and would take days of continuous use (probably weeks... if at all) to blow with 20A running through it, so I cant see 17A troubling a 13A fuse too much. At a guess I would say a week of continuous use at 17A might blow it, but a few hours a day probably wont touch it!

BS1362 fuse.

 

[Richard Burns]

Bussman data sheet for 1362 fuses

View attachment BS1362 bussman.pdf

at 1.6In-1.9In it will last 30mins+ so at 1.3In it will last forever.

 

[HappyHippyDad]

BS1362 fuse.

Sorry.. my mistake!