Some confusion with wiring my 30 amp relay and hobbs switch

[gnfanatic]

Help me out guys, I am installing a 30 amp relay and a hobbs switch for my secondary pump. This is what I am thinking.


#85 on relay is grd
#86 on relay is signal from hobbs?
#87 on relay is power to pump
#30 on relay is power from batt

I have noticed some people say #30 is power TO pump??
And How do i wire up the hobbs switch to the relay?? I was thinking of connecting it to 85 to complete the ground circuit? But then what do i do with 86??

Any help is appreciated!

thanks!

 

[garyk1970]

There are two parts to a relay....
1) coil (control of relay) 85 and 86
2)switch part... 30 and 87
87a isnt needed in this case so it wont be mentioned....

think of a relay thats a remote switch and in this case takes the load off the control (hobbs switch)

Start with the control ,terminals 85 and 86....
Doest matter which is ground or positive but it needs both to work.....so you can make the hobbs switch ground or positive.....

Heres how I wire up a relay in this configurcation,
Ignition power to hobbs.
Hobbs to 85
Ground to 86
Battery volts to 30
Second pump to 87

Hth

 

[David Husek]

Tie 30 and 86 together from battery. Run 87 to the pump. Run the ground thru the Hobb switch to 85.

or

Hook up 30 to the battery, Run 87 to the pump. Ground 85. Run battery thru Hobb Switch to 86.

You can run the power to the pump thru the Hobb switch and eliminate the relay,
make sure to install a fuse whichever way you decide....

 

[gnfanatic]

Dave, it doesnt matter what size ga wire from hobb switch to 86, correct?? its just a signal wire.

 

[turbo nasty]

Garys way has a switched control power vs davids have power present all the time.

 

[garyk1970]

That way if theres a sticking hobbs, it wont run key off....gage matters on the 30/87 wires....

 

[gnfanatic]

Thanks guys, I understand ga from batt and to pump is important. but what about signal wire from hobbs>>and the 85 grd wire>? I suppose 85 should have the same gauge as 87 and 30, no?

 

[garyk1970]

No ,a small gage wire on hobbs and relays control is fine...doesnt take alot of amps to trigger relay...

 

[gnfanatic]

Thanks gary but what about the ga wire fro the grd on the relay?? #85

 

[David Husek]

Dave, it doesnt matter what size ga wire from hobb switch to 86, correct?? its just a signal wire.

It doesn't matter what size wire, I would use 16 or 18 guage wire on 85 and 86. I would use the power from the fuel pump test wire behind the alternator to the Hobb switch to 86. This way there is only power when the car is running.