Fusing down fans to 3 amp

[vxwestie]

View attachment 16684struggling with3 amp fuses though

lol... 5 amp fusewire and scrape a bit off..

 

[ruston]

The rcd is going to save us all though , if it doesn't the regs are a waste of time (.Cos the supply cable still has the CPC attached doesn't it)

Vortex for one don't call for a 3 amp spur. Or they didn't before this.

Meant Vortice.

 

[Octopus]

And how many people also install dp isolation per instructions?

 

[Robert Turnbull]

Always fit a triple pole isolator, never though of fusing down till this

 

[Engineer54]

When will you all understand that BS fuses within Plug-tops and FCU's are there to protect the leads and cords supplying appliances/equipments, they are not for protection purposes of the appliances etc themselves!! Any protection afforded to to such items would be purely coincidental. BS 1362 fuses are not and never have been designed to protect appliances/equipment, in many cases the protection curve is far too coarse to afford any meaningful protection!!

So a bit like this Poll, Meaningless!! lol!!

 

[kingeri]

And how many people also install dp isolation per instructions?

I do..........always have. If not mentioned in instructions, I use a triple-pole isolator just for the fan.

 

[Octopus]

When will you all understand that BS fuses within Plug-tops and FCU's are there to protect the leads and cords supplying appliances/equipments, they are not for protection purposes of the appliances etc themselves!! Any protection afforded to to such items would be purely coincidental. BS 1362 fuses are not and never have been designed to protect appliances/equipment, in many cases the protection curve is far too coarse to afford any meaningful protection!!

So a bit like this Poll, Meaningless!! lol!!

Not taking an issue with you E but if the manufacturers instructions say fuse down to 3A how would you deal with it?

 

[Engineer54]

Not taking an issue with you E but if the manufacturers instructions say fuse down to 3A how would you deal with it?

They can state what they like, it would only apply to the connecting cord or lead, NOT the fan itself. If that required 3A protection, then it's down to the manufacturer to provide that protection themselves, not the circuit installer!!...

 

[Octopus]

They can state what they like, it would only apply to the connecting cord or lead, NOT the fan itself. If that required 3A protection, then it's down to the manufacturer to provide that protection themselves, not the circuit installer!!...

So the numpty Scheme assessor comes along and gives you a black mark as the manufacturers instructions haven't been followed....

 

[Engineer54]

So the numpty Scheme assessor comes along and gives you a black mark as the manufacturers instructions haven't been followed....

If you Allow him too, ...That's up to you isn't it!!

 

[Fin170]

So a bathroom fan is on average about 10-25w, for it to actually draw well over 3 amps something pretty spectacular will have had to go wrong, more along the lines of direct short than fan stuck on. In which event the 6 amp MCB will beat the fuse


Or maybe I'm looking at it the wrong way and the manufacture is assuming the circuit is protected by 5 amp fuse wire, in which case it's anybodys guess between the fuse wire, 3 amp or fire brigade

All crap anyway, fan manufacture should of made their cables safe for over .1A, same for those 9.5kw showers that are full of 4mm

In conclusion, 3 amp MCBs :lol:

 

[MarkieSparkie]

...I still maintain that in nearly every instance a 6mcb would blow first in the event of a fault....

Sorry mate but you are wrong in that assumption:
Comparing data for a 6A BS 60898 Type B MCBs or BS 61009 RCBOs from BS7671:2008+A1:2011 Fig 3A4 and a 3A BS1362 Fuse from the Bussman catalogue datasheet:
6A MCB requires a prospective overload current of 30A to trip in the conventional time.
3A Fuse requires a prospective overload current of between 12 and 18A in the conventional time.
[FONT=&amp]Therefore discrimination is likely to be achieved

Also, [/FONT]BS 1362 specifies breaking-time/current characteristics for fuses with a current rating of 3A, the required breaking-time ranges quoted are: 0.2–80s at 9 A, < 0.1s at 20 A and < 0.03s at 30 A.
BS 1362 fuse short circuit capacity is 6kA.