I'm the proud owner of a 2012 TD4 GS and I've been following recent topics to do with installing some sort of SAT NAV. So I got some piggy back fuses and had a go myself. Reading through these, there is talk of attaching the piggy back to F5 or F21 of the Passenger Fuse box. I have tried both of these, to no avail and the manual isn't clear either. I have attached a picture of my Fuse Box Contents could some one give me an idea of what I should do.

Thank you

Click image to enlarge

It depends what you need - in the past on my MY13 I have used F18 with a piggy back fuse connector - although It is permanently live so might not be ideal for you.
Paul

You need to purchase a circuit tester so you can then find a suitable ignition live feed.
I use one of these.
http://www.toolstation.com/shop/p84459

That's a good idea 'cause I'm not sure my piggy back connection is good