Kettle Lead Fuse Ampage - Make a different?

Hessian · 8 Feb 2011 at 17:13

Kettle Lead Fuse Amperage - Make a difference?****

I've just been spring cleaning my desk and computer, sorting out cables, etc. In moving my PC I realised I've somehow got 5 kettle leads, with the need for only 3. So I was looking at the cables trying to work out what goes with what and I noticed I've got 3 different fuse levels between the 5.

Leads I've got:
3 x 5A
1 x 10A
1 x 13A

The hardware is:
2 x LG E2240T
1 x Corsair HX 750W ATX Modular

In the past, I think I've just plugged in whatever cable was nearest, I didn't really think about a difference. Does it matter? It'll be going through a power strip extension as well. And the monitors both have transformer bricks too.

Baldbloke · 8 Feb 2011 at 17:30

P= v*I

P = Wattage,
V = voltage,
I = current,

or put another way,

I =p/v

This will give a "guide" as to which fuse to fit.

Often it is practical to fit a 5 amp fuse in a 750w appliance. This is because some equipment can have a brief power up surge in excess of its rated running current. Hence a 3a fuse, which the calculation suggest you should use, would pop.

Bet you wish you hadn't asked..

Hessian · 8 Feb 2011 at 17:32

So essentially all my plugs are fine to use? Is that what you're saying?

If 5A is fine for 750w? Will there be any harm in using the higher amperage plugs?

Baldbloke · 8 Feb 2011 at 17:38

I googled LG E2240T. It's a monitor, I see. Go with 3A ideally. But 5A should be fine.
Fuses offer less protection when an unneccesarily higher rated fuse is used.

As for the 750w psu, 5A should be good and be able to cope with power on surge.

Baldbloke · 8 Feb 2011 at 17:43

Just saw your response as I was typing 2nd post.

Safest thing to do is always use the smallest value fuse you can. This offers best protection. However, surge currents, usually when switching something on, can make render the calculation a guide as opposed to a rule. So often it is necessary to use the next value up.

PhilGQ · 8 Feb 2011 at 17:53

A fuse can survive a short spike of a much high voltage than rated. A 13A can survive a 35A current if its only very brief. A sustained current above 13A should make it pop though. Whether your pc bits can survive a 35A spike I don't know.