12v socket fuse and wiring.

[Gingerbread Man]

I have a 12v socket in my car. I fancy adding another, now is this a seperate fuse in the fuse box job, or can I combine it into the current wiring and fuse? Either way is pretty easy to be honest, but I was wondering what is the done thing.

[Mroad]

The wiring depends on the load you are planning to put on the system as there's a big difference in current draw from a phone charger to a heater. It also depends on who's using the car, if only you and you know the limitations then fine, if someone else is going to use it who doesn't have a clue then it needs to be belt and braces.
A couple of phone chargers running, no problem in coming off at the existing output side of the fuse but remember the total current drawn between the two can't exceed the original maximum rating of one socket. A couple of 12V heaters or 240V inverters then it needs to be belt and braces, add in another separate fuse and separate supply but make sure the supply can cope (wiring size and fuse rating).
Copy the wiring size from the existing socket for new runs and you shouldn't go wrong.

[Gingerbread Man]

Brilliant reply, thanks.

I'll run to a separate fuse. It's only phone chargers, satnav of similar, but as you says, belts and braces.

I think the original one I wired straight to the battery via a fuse so it could be trickle charged through it if needs be. Maybe I'll put this one on the ignition live side of things.

[eltax91]

Gingerbread Man said:

Brilliant reply, thanks.

I'll run to a separate fuse. It's only phone chargers, satnav of similar, but as you says, belts and braces.

I think the original one I wired straight to the battery via a fuse so it could be trickle charged through it if needs be. Maybe I'll put this one on the ignition live side of things.

I used a piggyback fuse holder and wired it in on a new fuse. This was for a cig socket to plug in a dash cam

[Penelope Stopit]

Gingerbread Man said:

Brilliant reply, thanks.

I'll run to a separate fuse. It's only phone chargers, satnav of similar, but as you says, belts and braces.

I think the original one I wired straight to the battery via a fuse so it could be trickle charged through it if needs be. Maybe I'll put this one on the ignition live side of things.

If you are using it as an ignition supplied outlet you will need to wire it through a relay that is supplied from a suitable size battery positive and make sure you fuse that supply, operate the relay pull-in coil with any ignition supply

If you dont relay it you could overload the chosen ignition supply