EU to UK plug adaptor fuse for laptop help pls

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mosy
Posts: 4111
Joined: 21 Sep 2007 20:28
Location: London

EU to UK plug adaptor fuse for laptop help pls

Post by mosy »

The adaptor I've bought to sit in the wall socket has UK 3-pins and takes the EU 2-pin plug the laptop came with. It is fitted with 13A fuse - should I swap to 3A please?

The laptop itself has its own AC/DC transformer adaptor, the sort that sits along the lead wire, which says:

Input 100-240V ~ 2.7A 50-60Hertz (the tild sign means alternating current)
Output 19.5V (Direct current symbol) 7.7A


The laptop starts charging OK with the 13A fuse in the wall socket adaptor, just worried if should be 3A. or maybe it doesn't matter?

Any help much appreciated.
Ta
JRobinson
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Joined: 5 Jan 2010 12:40
Location: De Frene Rd

Re: EU to UK plug adaptor fuse for laptop help pls

Post by JRobinson »

it sounds like it's only pulling 2.7A - so a 3A fuse would be fine, however if something goes wrong that the fuse needs to blow at 3A, it'll still blow when it gets above 13A, as these things tend not to stop at a certain amperage, so probably not really an issue.
It's probably more effort than it's worth to change it.
You might have a faulty box which is actually pulling 3.1A - then the fuse would be going all the time (very unlikely though)

personally I'd either buy the correct wire with the UK 3 pin plug on the end, or just cut the EU plug of, and re-wire with a new UK plug. It takes up to 240V, so no harm in this - if you know what you're doing. Either of these I'd just stick a 13A fuse in.

unless of course you travel in Europe a lot, and need the EU 2 pin socket more often. I take it the 2 pin socket isn't fused - they tend not to be.
mosy
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Joined: 21 Sep 2007 20:28
Location: London

Re: EU to UK plug adaptor fuse for laptop help pls

Post by mosy »

Thanks for the info. The laptop is short-stay in the UK so just a temporary need. As it's not mine, I'm treading carefully since it certainly wasn't cheap.

I decided to change the fuse to 3A (easy enough to flip out the fuse cover on the adaptor and I have several spares of both ratings) and it works with that. If it blows, then I'll assume a fault as the input 2.7A, is supposedly verified as a true measurement. I thought I'd read somewhere that BS fuses allowed a +20% tolerance but my brain turned to mush trying to work out what was relevant. As long as the laptop doesn't turn to mush, we'll be happy bunnies.
JRobinson
Posts: 1104
Joined: 5 Jan 2010 12:40
Location: De Frene Rd

Re: EU to UK plug adaptor fuse for laptop help pls

Post by JRobinson »

good point, newer plugs have an easy change fuse - older ones you need to unscrew.

sounds like you're ok though.
stuart
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Joined: 21 Sep 2004 10:13
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Re: EU to UK plug adaptor fuse for laptop help pls

Post by stuart »

Mosy,

I was waiting for a qualified electrician to give a certified answer. But in his absence here is a very uncertified one. There should be no need to worry. There is a reason why our plugs have fuses and continental ones don't. It is our 'ring' system where, without a fuse you can draw 35 amps before the relay in the fusebox trips. That's tasty and why we had the hoverboard warnings before Christmas where no-protection power supplies were included.

The fuse in a three pin plug is there to protect the plug and lead which won't take 35A and not the equipment. It also means that when there is a short only the plug fuse blows and does not effect every other device on the same ring circuit. A normal lead should take 13A. Thin old style thin lamp wire should be 3A (also there is the danger of exposed terminals to human touch if the bulb is missing).

Most reputable PC power supplies will have protection built into them - because that will be needed in other countries which will have the same PSU but with an unfused two pin plug (as you had). The fuse is further upline and will be greater than 3A or you wouldn't be able to plug heaters, hairdryers and stuff like that into the same socket.

HTH, and if anyone is electrically qualified please confirm or destroy my advice.

Stuart
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