Pennsylvania Code
Title 67 - TRANSPORTATION
Part I - Department of Transportation
Subpart A - Vehicle Code Provisions
Article VII - Vehicle Characteristics
Chapter 173 - FLASHING OR REVOLVING LIGHTS ON EMERGENCY AND AUTHORIZED VEHICLES
Section 173.4 - Wiring

(1) Wiring must be primary SAE rated and be of proper gauge to handle applied load. Ground wiring must be of equal gauge.

(2) Wiring may not be loaded to more than 80% of its rated capacity.

(3) The wiring must be permanently installed and routed through the vehicle in a manner to avoid short circuits or interfering with the operation of the vehicle.

(4) Grommets shall be used when wires pass through bulkheads and other sharp metal surfaces.

(5) Each accessory will be protected with the proper circuit protection as recommended by the manufacturer (that is, fuses or circuit breakers). The main circuit protection will be as close to the power source as possible.

(6) Additional wiring installed for emergency equipment may not impede or compromise the original equipment manufacturer circuits or original equipment manufacturer equipment functions as intended by the vehicle manufacturer.

(7) Tapping power off of original equipment manufacture circuits, such as in fuse blocks, must be only as recommended by the vehicle manufacturer. Tapping power off air bag or ABS brake and brake light circuits is prohibited.

(8) These requirements do not apply to flashing or revolving lights that are attached to a vehicle with a magnetic base.