Master electrical cut-off

[VintageracerNYC]

I tried a search to no avail. Does anyone have any experience of where and how to locate and wire a master electrical cut-off switch for racing. I have experience with older model carbureted cars but not late model ones which should be wired to probably both the fuel and ignition system.
Thanks in advance.
Jerome in NYC

 

[Bob Kenney]

The main relay, located behind the passenger seat and to the drivers side of the ECU controls the fuel pump and I believe the ignition.

Bob

 

[john@johnhudakracing]

Ideally, with one turn a corner worker should be able to completely disable the electrical system in the vehicle, in the event of an incident (e.g. gasoline spilled everywhere)

As the battery is front mount and engine/fuel mid to rear, ideally one turn would kill all power off the battery within the vehicle. It should be externally accessible and clearly marked with an SCCA sticker.

For the NSX, an easy way is to locate it up near the windshield poking up through the hood, and tap right into the main leads. I opted to put mine on the B Pillar and did some custom wiring mid-way back. Switch location and preference will be the deciding factor on how best to wire it in.

Ideally, use the more expensive type with alternator protection.

 

[Andrie Hartanto]

You want to cut all electrical from the battery and altenator.

You will want to locate the switch to be driver accessible as well as corner worker accessible. SCCA pro requires it to be within 12" of window opening and driver accessible while buckled in.

 

[VintageracerNYC]

Thanks guys for all the help! your the greatest!

 

[RacerX-21]

Hi Jerome,

SCCA, FIA, NASA, etc. require total electrical cut-off to minimize problems like an electric fuel pump flowing into a flame. To build this electrical cut-off properly, you will need to add a substantial amount of positive battery cable. This cable will run through a main cut-off switch before it goes to everything or anything on the car. I build my cars with (2) external switches for the driver and passenger side (In case one is not accessible). The switches need to be 4-terminal so that you can also pass the alternator power through it. If you only cut-off the positive lead to the car, the alternator will still produce enough power to keep the car running. There are other ways to do this, but this is the only way that wont get you disqualified if checked.

I mounted my cut-off plates to my cage for internal and external access, you may not always be conscious after a wreck.