Specifications

SVI Trucks

Freightliner 4-Door Demo

SVI #917 01/05/15

LOW VOLTAGE ELECTRICAL SYSTEM- 12 VDC

General

Any low voltage electrical systems or warning devices installed on the fire apparatus shall be appropriate for the

mounting location and intended electrical load.

Where wire passes through sheet metal, grommets shall be used to protect wire and wire looms. Electrical

connections shall be with double crimp water-tight heat shrink connectors.

All 12 VDC wiring running from front to back of vehicle body shall be run in full length electrical wiring raceway

down each side of body.

Wiring

All electrical circuit feeder wiring supplied and installed by the fire apparatus manufacturer shall meet the

requirements of NFPA Chapter 13.

The circuit feeder wire shall be stranded copper or copper alloy conductors of a gauge rated to carry 125 % of the

maximum current for which the circuit is protected. Voltage drops in all wiring from the power source to the using

device shall not exceed 10 %. The use of star washers for circuit ground connections shall not be permitted.

All circuits shall otherwise be wired in conformance with SAE J1292, Automobile, Truck, Truck-Tractor, Trailer,

and Motor Coach Wiring.

Wiring and Wire Harness Construction

All insulated wire and cable shall conform to SAE J1127, Low Voltage Battery Cable, or SAE J1128, Low Voltage

Primary Cable, type SXL, GXL, or TXL.

All conductors shall be constructed in accordance with SAE J1127 or SAE J1128, except where good engineering

practice dictates special strand construction. Conductor materials and stranding, other than copper, shall be

permitted if all applicable requirements for physical, electrical, and environmental conditions are met as dictated

by the end application. Physical and dimensional values of conductor insulation shall be in conformance with the

requirements of SAE J1127 or SAE J1128, except where good engineering practice dictates special conductor

insulation. The overall covering of conductors shall be moisture-resistant loom or braid that has a minimum

continuous rating of 194°F (90°C) except where good engineering practice dictates special consideration for loom

installations exposed to higher temperatures. The overall covering of jacketed cables shall be moisture resistant

and have a minimum continuous temperature rating of 194°F (90°C), except where good engineering practice

dictates special consideration for cable installations exposed to higher temperatures.

All wiring connections and terminations shall use a method that provides a positive mechanical and electrical

connection. The wiring connections and terminations shall be installed in accordance with the device

manufacturer’s instructions. All ungrounded electrical terminals shall have protective covers or be in enclosures.

Wire nut, insulation displacement, and insulation piercing connections shall not be used.

Wiring shall be restrained to prevent damage caused by chafing or ice buildup and protected against heat, liquid

contaminants, or other environmental factors.

Wiring shall be uniquely identified at least every 2 ft (0.6 m) by color coding or permanent marking with a circuit

function code. The identification shall reference a wiring diagram.

Circuits shall be provided with properly rated low voltage overcurrent protective devices. Such devices shall be

readily accessible and protected against heat in excess of the overcurrent device’s design range, mechanical

damage, and water spray. Circuit protection shall be accomplished by utilizing fuses, circuit breakers, fusible

links, or solid state equivalent devices.