changing fuses on European to UK travel adaptors

[BS3036]

5A is also a preferred size, isn't it?

Not according to BS 1362:1973. Have you got a later copy?

 

[ericmark]

For the 13A plug fuses are available in following sizes.
1A = 230W
2A = 460W
3A = 690W preferred size
5A = 1150W
7A = 1610W
10A = 2300W
13A = 2760W preferred size

5A is also a preferred size, isn't it?

I have not up-dated my copy of Inspection and testing of in-service electrical equipment and it may have changed but in my old copy only 3 and 13 amp fuses where given as preferred sizes. Since 3A is max for 0.5mm² cable there does seems some sense in this. However looking at table 52.3 that 0.75mm² now seems to be minimum size so a change to 5A would seem likely. But of course there must be loads of appliances still with 0.5mm² cable so I would have expected some delay in changing preferred sizes.

However since 1, 2, 3, 5, 7, 10, and 13 amp fuses are still available I see no real problem in matching the fuse to load rather than to cable. With many plugs being moulded to the cable it is often hard to identify cable size used but wattage ratings are normally found so although it theory we are to select the fuse to protect cable with any fusing required to protect equipment being included in the equipment rather than plug to select according to equipment rating is unlikely to be a problem.

It also has added advantage of both being easier to change and likely to give better fire protection to the equipment. As far as I can see the move to protecting cable rather than equipment was only made so exported equipment used with the inferior continental fusing arrangement would still be protected.

I was trying to answer your request

The fuse is there to protect the cable, so compare yours to the various types on sale in one of the big DIY sheds ( icon_cry.gif ) to see what the sizes are, and use fuses no larger than the maximum rating for flex those sizes, details of which some kind soul will soon post here as I don't have that info with me right now and I can't remember the limits for the very small sizes...

 

[ban-all-sheds]

Not according to BS 1362:1973. Have you got a later copy?

No - got 1973 (Amd 1981).

And you're right:

5.3.2 Rated current of the fuse link. The rated
current may be any value not exceeding 13 A. For
use in plugs, the preferred rated currents are 3 A
and 13 A.

I did think that 5A was also preferred, probably on the basis that those blister packs of assorted fuses always contain 3, 5 & 13.

Oh well - live & learn - if that's the worst mistake I make today I'll be happy...

Anyway - talking of mistakes - time to get back to work..