Discrimination between BS1362 fuses

[kingeri]

Fused spur off ring with 13a fuse supplying 4x 3-gang fused socket outlets for a small computer area. Loads not going to be massive. Should the 4x 13a fuses in the 3-gang sockets be changed for a lower rating, e.g. 10a, to allow for discrimination between sockets outlets and the fuse in the FCU?

In theory I think yes, but then again how often are multiple fuses used, e.g. when we use a power tool plugged into an extension flex. But then again, I'm talking about fixed wiring, so it's a different situation.

 

[ian.settle1]

Only BS1362 fuses which are shown in the regs are 3A & 13A as I don't have my regs handy don't know if there is a curve table as the other type of circuit protection devices to compare.

 

[kingeri]

I have a big box of BS1362 fuses, obviously loads of 3,5 &13s, but also for some reason I've got loads of 1,2,7 & 10s as well, although never had cause to use them. Maybe I'm just looking for an excuse!

 

[Engineer54]

Only BS1362 fuses which are shown in the regs are 3A & 13A as I don't have my regs handy don't know if there is a curve table as the other type of circuit protection devices to compare.

Your correct, they are the only two ratings that's ever been officially recognised by the IEE/ITE as far as i know!!

Over the years i've seen all sorts of BS1362 fuse ratings, even 15A!! I brought a couple of these 15A with me over here and had them checked by the contractor on his MCCB injection test equipment, expecting the worst, ...and believe it or not, they performed fine. ...lol!!

 

[kingeri]

Your correct, they are the only two ratings that's ever been officially recognised by the IEE/ITE as far as i know!!

Over the years i've seen all sorts of BS1362 fuse ratings, even 15A!! I brought a couple of these 15A with me over here and had them checked by the contractor on his MCCB injection test equipment, expecting the worst, ...and believe it or not, they performed fine. ...lol!!

Eng, I'd be interested in your view on the original question......if you don't mind me troubling you

 

[Engineer54]

Eng, I'd be interested in your view on the original question......if you don't mind me troubling you

Any discrimination you will achieve is going to be on overload conditions and possibly on instantaneous between the 3A and 13A. On short circuit (instantaneous) i doubt very much you would achieve discrimination between a 10A and 13A fuses. Pot luck then, one or the other or both!! lol!!

EDIT...

Remember the BS1362 is primarily there to protect the flexible cables rather than the appliances the cords are connected too. No matter what others here have to say about it!!

 

[Guest55]

you wont get discrimination between 13a & 10a 1362 fuses , not a big enough difference in the pre-arc & let-through energy values
you'll need no bigger than 5a in the plug-tops to achieve it , but i wouldnt try and to get discrim. with plug in appliances anyway.

 

[HandySparks]

Why not just install 6 ordinary double sockets? (Or do you already have the fused 3-gang sockets?)

 

[markc123]

Why not just install 6 ordinary double sockets? (Or do you already have the fused 3-gang sockets?)

To be fair, that was my original thought....but as for some reason i read the thread as 'domination between BS1362 fuses' at first, then i thought id maybe missed something so neglected to comment.

 

[kingeri]

Why not just install 6 ordinary double sockets? (Or do you already have the fused 3-gang sockets?)

The sockets were already installed....looked like a DIY job. I was doing an EICR, just wondered if there needed to be discrimination here, as there are 2 cascading 13a fuses. No big deal, I know, but just got me thinking, that's all.

 

[telectrix]

sign the cert. get paid, next job.