250V 20x5mm glass fuse. 7630mA??

Question

I am trying to repair a venerable Coleman camping gaz 240V to 12V cigar lighter socket converter.

The fuse has blown, and after a lot of hassle (t Input 240V AC 50Hz 0.6A

Output 13V DC 5A 65W

As I type this I am wondering if I have read it correctly. Isn't 7630mA 7.63A? Which seems a factor of 10 higher than the 0.6A shown as the input power. I've just re-checked (magnifier App on Android is a good thing) and it definitely says 7630mA.

240V x 0.6A should be 144W which seems suitable for an output of 65W.

Given all of the above, what would be a reasonable fuse to use to replace the blown one?

8A if I can find it? I have had no luck searching for the value shown on the fuse.

Is this higher rating assuming a surge on start up or device connection?

Cheers

Dave R

Andy Burns · Accepted Answer

Sure it doesn't say T630mA?  Which would be a slow blow fuse ...

The Natural Philosopher · Answer

No such fuse has ever existed, its 750mA most likely or even more likely 630mA.No. You have simply misread the fuse.

David · Answer

Thanks.That could explain things.I had a great deal of difficulty reading the fuse due to the small size so could well have confused a T with a 7.Still slightly bemuse about the fine detail.Why 630mA instead of a nice round number?Will go and have yet another look in a while.CheersDave R

Andy Burns · Answer

For whatever reason, the series of miniature fuses goes32mA, 40mA, 50mA, 63mA, 80mA, 100mA, 125mA, 160mA, 200mA, 250mA, 315mA, 400mA, 500mA, 630mA, 800mA, 1A, 1.25A, 1.6A, 2A, 2.5A, 3.15A, 5A and 10A.

The Nomad · Answer

On Fri, 23 Jan 2026 17:19:18 +0000, Andy Burns    wrote:Because the value of each is approx 1.25 times larger than the previous valueAvpx

The Natural Philosopher · Answer

Its all to do with harmonisation of standards. 500mA is old hat - 630 mA is part of the E number scheme

Standard Current Ratings (Amperage) Standardized amperage values for 5x20mm fuses, commonly found in 250V AC, include:

Low Current: 32mA, 40mA, 50mA, 63mA, 80mA, 100mA, 125mA, 160mA,

200mA, 250mA, 315mA, 400mA, 500mA, 630mA, 800mA

Ampere Ranges: 1A, 1.25A, 1.6A, 2A, 2.5A, 3.15A, 4A, 5A, 6.3A, 8A,

10A, 12A, 12.5A, 16A

Note that L fuses are deprecated. The replacement is G for General usage

The Natural Philosopher · Answer

strictly approximately the tenth root of ten...Resistors and capacitors went E12/24 but fuses went E10...

alan_m · Answer

I find a mobile smart phone good for this type of thingUse the smart phone camera in its normal or macro photo mode to take a photoView the photo and zoom in to read the text

me9 · Answer

630mA is a standard fuse value.

Cursitor Doom · Answer

On Fri, 23 Jan 2026 17:19:18 +0000, Andy Burns    wrote:630mA slow blow. I'd put money on it.

Alan J. Wylie · Answer

250V 20x5mm glass fuse. 7630mA??

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