kustomizer

does anyone out there have a wiring diagram to wire a race car with relays and all any help would be appreciated thanxs scott

mytmouz

http://forums.racingjunk.com/viewtopic.php?t=4262

jsims0540

jsims0540

Did anyone every answer your question? I now have the same issue using a Painless Installation. fuse block, a 8 switch panel.

john910

if im going to install 3 relays should they be close to fan, pump. or close to switch? also what gauge wire is safe to supply power from battery to all 3 relays ex.10 or 12 gauge. thanks

indcontrols

Always put the relay as close to the load (pump, fan, etc.) as practical - not just a myth... here's why...

The contact inside the relay must make (close) and break (open) the electrical load as it is turned on and off. The more current draw, the harder it is on the contacts to make and break. If the relay is 12 feet away, that 12 feet of wire has some electrical resistance... As the pump will draw the same amount of power (in watts), the relay must now also overcome the resistance of the wire length as well as the power to run the pump (ie; more current)... It must also break the larger current as well as dissipate the additional heat - shorter relay life...

As for the wire size, it is totally dependent on max operating (usually max occurs during starting) of the load / motor. If you're supplying more than one load, you must add them up - Below is a chart (credit* engineering toolbox) for 12v DC systems wire amperage ratings - This is based on PVC (crap wire) 75 and 90 degrees C rated wire common to automotive hook up wire.... I recommend going up a size once you figure it out !!! I use 150 or 200 degrees C rated wire (but that's cheating, I run a wire company...) You will notice that the wire run length must also be taken into consideration - for the reason I mentioned above. Be sure that the protection device (fuse, breaker, link) is sized according to what the wire can reliably hold...

American Wire Gauge (AWG)
Length
(feet) Current (amps)
5 10 15 20 25 30 40 50 60 70
15 16 12 10 10 8 8 6 6 4 4
20 14 12 10 8 8 6 6 4 4 4
25 14 10 8 8 6 6 4 4 2 2
30 12 10 8 6 6 4 4 2 2 2
40 12 8 6 6 4 4 2 2 1 1/0
50 10 8 6 4 4 2 2 1 1/0 1/0
60 10 6 6 4 2 2 1 1/0 2/0 2/0
70 10 6 4 2 2 2 1/0 2/0 2/0 3/0
80 8 6 4 2 2 1 1/0 2/0 3/0 3/0
90 8 4 4 2 1 1/0 2/0 3/0 3/0 4/0

Hope this helps !

indcontrols

Chart didn't turn out well !! Here it is in readable form... http://www.engineeringtoolbox.com/am...uge-d_730.html
John[ATTACH=CONFIG]91[/ATTACH]