Fuse Type

[NC68]

What fuse (3amp, 5amp, 10amp or 13amp) should go in a IEC lead? Does the length of the IEC lead take into effect or does any fuse matter to make it safe?

[ChuckFickens]

it's nothing to do with the lead type,

What are you powering with it?

If it's a kettle then you need a 13amp if it's a computer then 3 or 5amp

[NC68]

Cheers for that. Yeah some are for a computers and some for monitors. So what is the general rule for using the correct fuse in plugs/leads etc?? How can you be certain that the correct one is used?
Many thanks :D

[ChuckFickens]

I'd put a 5amp in for computers or monitors,

The general rule is

Up to 600 Watts 3 Amps

Between 600 Watts and 1000 Watts (1KW) 5 Amps

Between 1KW and 3KW (3000 Watts) 13 Amps

[NC68]

Cheers for this. Sorta making sense now. The general rule comes in handy! Simple question, but what about when electrical items don't have labels on to tell you what fuse to use or amount of amps it is using? Going on the rule W=AxV how would you find the fuse to use in a desk lamp, if all you know is W=Ax240? Hope this makes sense?

[ChuckFickens]

Amps = Watts/Volts

so a 100 watt bulb on 240v would be

A = 100/240

So A = 0.146

A 3amp fuse is the lowest you can get for a domestic plug so you'd use a 3amp for a 100watt bulb

[Hymie]

All electrical equipment with an IEC inlet will be fitted with internal fusing for protection in the event of a fault. Theoretically, no fault within the equipment should cause the plug fuse to operate. The plug fuse is only there to protect the lead in the event of damage. In most parts of the world there is no plug fuse within the IEC lead, and protection of the lead relies on the building installation.

It follows that you may safely put 13A fuses in all IEC leads, regardless of the equipment used with the lead. This has the advantage that you will never suffer nuisance fuse operation due to leads fitted with a low current rated plug fuse, being used on higher power equipment.

[Hymie]

In the following post, �knobby�� will explain how 0.75mm2 IEC leads are used safely throughout Europe (with no plug fuse), with overcurrent protection being provided by the 16A building supply � whereas in the UK they cannot be used with 13A fuse protection.

[north star]

I'm with Hymie, the fuse is there to protect the cable.

[NC68]

Cheers for all the answers. Understand and makes sense now. Many thanks

[Hymie]

There are a considerable number of differences in electrical regulations between the UK and mainland Europe. However, in most of Europe, standard outlet sockets are rated at 16A and are protected by fuses/breakers appropriately rated. As stated, their standard plugs have no provision for additional fusing.

In the UK, standard outlet sockets are connected to a �ring main� with either 30A or 32A fuses/breakers providing overcurrent protection. The practice of wiring a series of socket outlets in a �ring�, as in the UK is not used within mainland Europe. Although up to 32A is available at UK socket outlets, plugs will be fused at a maximum of 13A, resulting in a similar current available to equipment used throughout Europe.

Harmonisation of safety standards between member States means that electrical equipment can, by and large, be used throughout Europe without a problem. However there are National Differences to safety standards (which reflect local conditions), which means this does not hold true for all situations � but as you know, this is a subject I don�t understand.

[Disco Fever]

You were nearly right Chuck it's 0.416 amps for a 100 watt lamp....

Hymie, you'll find that 99% of IEC leads says on the socket part that it is rated to only 10 amps so a 13 amp fuse would be wrong as the lead could be overloaded and cause a fire....

The 17th Edition IEE regs says that 0.5mm flex is rated at 3 amps, 0.75mm is rated at 6 amps, 1mm is rated at 10 amps 1.25 mm is rated at 13 amps and 1.5mm is rated at 16 amps....

[Hymie]

The IEE regs are not applicable to the appliance IEC power cord � the requirements for this are specified within the relevant product safety standard. Even so, for PCs & monitors 0.75mm2 IEC leads are rated at 6A, however this is 10A - providing that the lead length does not exceed 2m.

So a more important consideration when using IEC leads, is not the plug fuse rating, but that the appliance rating does not exceed the lead rating. But if you have a PC or monitor rated at over 10A, you have got the mother of all PCs/monitors.

It is not a requirement that circuit fusing must not be greater than the rating of components within a circuit. It is perfectly acceptable to have a 10A rated lead, fused at 13A � but the lead cannot be rated at 13A (it is rated at 10A).

Around 10 years ago, Which? reported much as other have stated here, that UK mains plugs must be fitted with fuses compatible with the equipment rating (3A, 5A, 10A or 13A) � they received many letters pointing out that this is not so.

[Hymie]

Unfortunately, none of my last post was pasted from anywhere (otherwise I would supply the source) � not that copying guarantees accuracy/correctness of content.

But since you are so knowledgeable on the subject, I would be interested in precisely which section(s) of my last post is complete nonsense.

Perhaps others might recall the Which? item, and confirm the fact that they retracted their statement that UK mains plugs are required to be fitted with fuses rated at less than 13A.