i have installed a fuse box under my bonnet to run my custom wiring through as to not take powe from any existing circuits so i do not overload any circuis and it also makes t easier for me to add change or find faults in the future. right now i have cables from the battery to the fuse box and am then running constant power to my LED's (activated by triggers and internal switches so i can use them when car is on or off).
my question is when i add something that i only want on when in acc where is best to get the acc trigger from? i do not want to take power from another circuit i only want to use the ignition switch to control power passing through my circuit when in acc mode. the only place i can think to do this would be directly from behind the ignition switch (i assume this is the key barrel unit). i was hoping to find somewhere under bonnet. i am looking for a place that will not interupt any other circuit as i dont want to take power from another circuit. i hope people can follow what i am saying and help me out
i suppose i am looking for the main acc cable under the bonnet. i would then replace the cable runnning from my battery to my fuse with the cable from the igniton to my fuse. or would i be best off tapping it in so it acts as a switch fo my custom power wire?
would it work if i used the power cable for say the radio or wipers before it goes into the standard fuse box? or is it only acc controlled after passing through the fuse box ( i am reffering to the under bonnet fuse box not the one in the drivers footwell)
the reason to take it before the fuse is as to not overload the circuit as i will be running my own fuses. will the standard wiring have any problems producing enough current for many devices such as an inverter, gps locating cameraa recording system (like what is in taxis) and possibly other devices.
i would be after the thickest guage cable capable of supplying the most amount of power through it or something that will just switch my custom wire on and off.
http://i1166.photobucket.com/albums/q608/maat1985/MY%20Magna/20120923_114509_zpsf3606442.jpg
http://i1166.photobucket.com/albums/q608/maat1985/MY%20Magna/20120923_114441_zps24498abd.jpg

Was just thinking properly about this and realised i have probably over complicated my thinking.
4 pin relays would be the answer.
After my fuse box i install a 4 pin relay so that my custom power wire passes through pin 2 and 4. Pin 1 is input from an acc source (wher do i best take this from before the standard fuse box?) And then pin 3 is grounded out. Meaning power is supplied through my wire direct from battery however the circuit is only active when the acc supplys power through pin 1.
Cant believe i didnt think of this before. When i did my fog lights the internal switch is where the acc power is tapped into.

Yeah, relay would be fine. And you should be able to score it from anything requiring ACC to run. Scope out the diagrams. ACC wiring in these is usually solid blue. But check first.

Mike

Glad i seemed to have worked it out. Cant believe it had me stumped so badly. I have the service manual here and i have found the wiring diagrams to be so useful so far.