Electrical Relay Question

[Curt C.]

I want to use a relay on my fuel pump. The fuel pump requires a 7.5 amp fuse. Do I need a 7.5 amp relay or can I use the standard automotive relays which are rated at 30 amp. I am slowly getting a handle on this electrical stuff. Thanks for the replies.

[Edbo]

Use a relay at least double the fuse amps. Bigger is better.
30A would be excellent.
You should still use the recommended fuse, to protect the pump motor.

HTH, Ed

[Curt C.]

Thanks Ed.

[petek]

(going to sound like a real "duh" if you already know this, but I'll offer it up anyway...)

Don't forget, the fuse goes on the contact side of the relay, not the coil side of the relay.

[vettestr]

Curt,
Another consideration should be wire size for the LOAD. The load or side of relay that supplies the current to fuel pump should be a minimum of 14 AWA gauge wire. The length of wire needed should not be long enough to demand a larger wire gauge.
Since we are talking about an electric fuel pump = concern with impact or turnover is a thought. Painless sells a relay setup for this concern.

[Bruce Edwards]

You may wish to install a fuel pump shut off tied in to your engine oil pressure as a safety. When the motor is not running no pump. When the engine is cranked and oil pressure goes up the pump comes on. Can cut down on those nasty fuel feed fires if you have a problem.

Bruce Edwards
Gemini Motorcars Inc.

[Curt C.]

Thanks guys. I just recently learned the power of the relay. Petek, no, I never really thought about that. So fuse goes between the relay and the pump in this instance? I already have the ground wired to a oil pressure switch so I think I am safe there. I will make sure to use the appropriate sized wire.

Curt