Vehicle electrics

[Ben]

I will soon be needing to install a couple of electrical items in my car. These will not be powered by the cigarete lighter socket - they will be hard wired in.

What i want to avoid is tapping in to existing wires - i want to do it properly.

I want to take a feed from the fuse panel at the right hand (drivers side) of the dashboard. The feed MUST be controlled from the ignition (no key = no power) thus no battery drain.

I have plenty of vacant fuse sockets. What is the best way to choose which one to use? Do i have to check each socket with a multimeter to find which ones are ignition based?

If i have just answerd my own question, my next is thus. What type of connector do i need to connect a wire to the rear of the chosen socket?

How thick should this wire be?

I know the brown wire on my car is negative / earth and am i correct in assuming that this is just connected to the chassis (chassis return)?

Currently i plan to install 2 items on this wire, both are 12v. What would the correct fuse rating need to be?

I wish to use this method of install as a protection against other electrical items on the car being damaged and providing an obvious and safe point for any other powered items.

Many thanks

[dansansome]

yes to the multimeter.

i cant answer the socket type required, sorry.

you are correct that the negative wire will eventually find its way be to the car's chassis.

the other bits both sort of tie in together.

the fuse needs to be about 10% bigger than the total current expected to be drawn by the two items when working flat out.

eg, if 1 item draws 1A (max), and the other draws 3A (max), then you will get away with a 5A fuse. if each item is individually fused (normally the fuses hide inside the cigarette lighter adaptor), then the fuse in the car's fusebox is only there to protect the wire from burning out.

however i would probably just use a 10A or 20A fuse and make sure that each item is still protected by a fuse rated the same as the original.

this leads on to the wire size. basically, when you have decided what rating you want to use in the main fuse box, just find another rated the same, and copy the wire size coming off it.

hope this helps

[Ben]

I've changed my mind on the wiring, will tap in to existing lives, earths and switchd lives.

I'll use the live to the radio, the earth to the radio and the switched live go pin 20 on the climatronic.

scotch locks

fitting 3 things, multimedia adapter for the MFD2, freeview, and nokia ck-7w bluetooth hands free.