hi everyone

its my first doing the wiring and i would like some tips. I have serchead but i couldnt find a table to size the wires, for example:
current(A) X section (mm² or AWG). Should i use the table or take in count the voltage drops and use a formula?

It really depends on the wire - it should come with some sort of datasheet about it. Remember than length is a large factor - if it's a very short length you can get away with thinner wire, but I wouldn't push it too much.

We use tefzel wire, and use mostly 22 gauge, with 20 gauge for higher current things such as our waterpump and radiator fan. I'd like to have run 24 gauge for the large number of sensor wires running to the datalogger, but we were unable to get a roll of it in time before the car running goal and resorted to 22 awg again.

Hey,

Just adding on to that, a quick search on google gives us a general chart of wire gauges to current capability. These charts, however are just a rule of thumb, and it is always prudent to consult the datasheet of the wire.

http://www.cablesandconnectors.com/wiregauge.html

http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity

Basically, you'd be interested in specifying wire that's about 1.5 to 2x your potential peak current flow. As analog sensor data doesnt go past an amp, we selected 24 gauge to work with. Only reason why we did not go above 26 gauge is that above AWG24, wire becomes really hard to work with and crimp, i.e. fiddly.

Hope that helped.

Richie Wong
Electron
University of Auckland FSAE

It would be wise to add shielding by means of twisted pair or shield wrap around any crank/cam position sensors and coil/injectors. We had a problem on our last car with interference from the starter causing us to drop camshaft position during cranking, which made starting a hassle.

Make sure you heatshrink your final loom. We use Raychem. Looks really neat too!

Raychem is awsome quality stuff. But it can be expensive if you don't have good hookups. If a team is really tight on money their is nothing wrong with using high quality electrical tape. Just take time wrapping it up and if you do a good job it will still look really neat.

There are some excellent wiring tips posted in this thread...

http://fsae.com/eve/forums/a/tpc/f/125607348/m/25010656541

quote:

Originally posted by Prohet][:
...their is nothing wrong with using high quality electrical tape. Just take time wrapping it up and if you do a good job it will still look really neat.

Agreed, but still use a heat gun or a soldering iron to melt the end of the electrical tape; electrical tape will start to peel and allow for no protection and not to mention you will get that black glue all over everything. By melting it to itself (CAREFULLY), you will prevent this from happening. This is a professionally accepted practice, I work for the electric company and see it done in relay wiring all the time wherever electric tape is used.

Steve