This NHRA-legal 4-terminal switch features an alternator interrupt circuit for cars with one-wire alternators. When the switch is turned off, the alternator exciter circuit is also cut off to prevent the alternator from feeding back into the ignition system. Wiring instructions are included. Accepts 3/8" ring terminals. Rated for 175 amps continuous current through the main terminals and 20 amps through the alternator circuit.
We also offer a Master Battery Cutoff Switch with Alternator Protection (Part No. 4430) which re-routes the alternator output to ground, preventing damage to the alternator circuitry.