Are we allowed to use 5 amp fuses in 13 amp plugs? | on Free Electrical Advice - Electricians Forums (2024)

I work for a charity (Besom) that gets equipment that needs to be PATted. A lot of these come with 5 amp fuses. Please do the regulations
allow you to use 5 amp fuses, or are you supposed to change them to 3 amp? Most of these devices are low power & they will run perfectly
well on a 3 amp fuse.

But the latest device is different. It is a Morphy-Richards iron model 42680. This has a 5amp fuse & is rated 6amp. I would like to change this to a 13amp fuse, but how do I tell if the cable will carry this?

Thank you, Mark

mark641 said:

I work for a charity (Besom) that gets equipment that needs to be PATted. A lot of these come with 5 amp fuses. Please do the regulations
allow you to use 5 amp fuses, or are you supposed to change them to 3 amp? Most of these devices are low power & they will run perfectly
well on a 3 amp fuse.

But the latest device is different. It is a Morphy-Richards iron model 42680. This has a 5amp fuse & is rated 6amp. I would like to change this to a 13amp fuse, but how do I tell if the cable will carry this?

Thank you, Mark

Click to expand...

This page may be helpful: - Manufacturers have now standardised ratings to either 3A or 13A - I believe these have always been the only ones that were 'officially' in the standard, though other ratings were quite widely used, including the 5A.

From that site:

Manufacturers have now standardised plug fuse ratings to be either 3A or 13A. However, 5 Amp fuses are still used in some older equipment and are available to buy.​

Which isn't terribly helpful in your case.

Where does it state 6A as the iron rating? If it comes with the manual then the manufacturers instructions should be followed as they designed it. It is also sometimes moulded into the plug. Having said that, there is no 6A fuse, and 10A fuses are available but used rarely in my experience.

It may be difficult to determine the cable size if it is a moulded plug, though some flexes do say the conductor size on them (2 x 0.75, 3 x 1.5) etc. It would probably need to be 1.25mm2 in size or larger to safely be protected by a 13A fuse.

Having said that, a "6A" (In reality it will be rated in Watts) iron is unlikely to blow a 5A fuse in reality. The factor is about 1.6, so a 5A fuse would likely blow at 8A or so.

Remember, the fuse is there to protect the cable to the appliance.
If there are sensitive parts inside the appliance that can’t survive an over current protected by the plug, they should be protected by a fuse or similar within the appliance.

BS 1362 allows for any rating of fuse up to 13A
However, normally the ones available are
1,2,3,5,7,10 and 13A

So in the absence of manufacturers data, any fuse that is marked as compliant with BS 1362 AND
a low enough rating to protect the cable in event of a fault
A high enough rating to power the full load of the appliance continually
Take into account short duration surges and where possible not blow on something like a filament rupture of a lamp.

Would be acceptable in my opinion.

You say, lots of equipment comes to you with 5A fuses and you change them for 3A fuses.
I don’t see the reasoning behind this unless the cable is under 0.75mm sq.

If you are portable appliance testing, you at the very least need to understand the processes & criteria for acceptance and have to hand the code of practice which documents these.

Table 10.6 in the cop shows which fuses are generally used (including 5A) and where they are used.

Primarily if the appliance/manufacturer states 5A, or 3A and so on, that's what should be fitted.

However if the cable size is smaller than in table 10.6 for the fuse size then the cable needs replacing as the fuse is unsuitable for the cable.

So, an appliance states 13A fuse, but the cable is 0.5mm^2 then although a 13A fuse fitted would be appropriate for the appliance, it is too big to protect the cable (table 10.6).

Therefore it cannot pass pat unless it is repaired with the correct cable.

In your case, therefore it depends what size fuse is stated by m.r. for this iron charger and the cable size (although if the cable is original it's likely to be suitable)

telectrix said:

what's wrong with cutting the head off of a 1" roofing bolt. fits perrf*ck.

Click to expand...

The cut end would go rusty!

Julie. said:

The cut end would go rusty!

Click to expand...

dang gosh darnit. forgit to mention the IP 67 plug (top).

telectrix said:

what's wrong with cutting the head off of a 1" roofing bolt. fits perrf*ck.

Click to expand...

You could do that and then make a bolt for the door

Ziggie said:

You could do that and then make a bolt for the door

Click to expand...

Seen a live 0.22 cartridge as a link once at a RAF MQ

Pete999 said:

Seen a live 0.22 cartridge as a link once at a RAF MQ

Click to expand...

True though

Pete999 said:

Seen a live 0.22 cartridge as a link once at a RAF MQ

Click to expand...

And an even better instant.
An I.T. company selling recovery solutions sent a dummy bullet to potential customers stating " if you dont have proper recovery procedures in place , you might as well use the enclosed. They sent it to customers in Northern Ireland during the troubles.
This was not well received.