[Jesper H]

Ehh - You allready know that; what Amp fuse blows ?
I guess it's a 10 Amp - so You have 10 Amps x 12 Volts = 120 Watt.

But what is a "3-in-one" ?

 

[Jesper H]

Ah - OK - actually I have one somewhere - though it has a USB plug instead of the 3rd lighter plug.
But I suspect that it is the accessories that are the culprits; check how much power they draw each, add it all up and see if You pass the 120 Watts.
If not - then it could be a faulty 3-in-1.
If You are a DIY-guy - open it and check for faults - and fix them.
If not - send it back to where You bought it ;o)
Hmm - one more thought though; the cigarette lighter plug has one problem by design; I have experienced that when plugging something in, a spark can appear before the center pin has frim connection to the buttom of the plug. Perhaps You could try plugging your accessories into the 3-in-1 before plugging the 3-in-1 into the car socket.