2. Crimps and Terminals
Before starting any wiring work for Caltrans, it is highly recommended that prospective vendors refer to the most recent version of IPC-A-620 (Class 2). " Requirements and Acceptance for Cable and Wire Harness Assemblies ". This document will be used by Caltrans inspectors as part of quality assurance acceptance inspections. Crimping references from Molex and others are listed in the Reference section.
2.2 Crimps and Tools
- The connector manufacturer’s recommended application specification shall be followed for proper termination of crimp terminals.
- Acceptable crimp connections shall be gas tight. Gas tight connections are like a cold weld and will remain corrosion free. Gas tight crimps are only achieved with use of the proper tools. One type of tool for installing crimps and terminals in wire size 22 to 10 gauge is the crimp manufacturer’s recommended, ratcheting, compound lever type tool that must go through a full crimp cycle before releasing. If there are questions regarding crimps and proper tooling, please call Caltrans, Division of Equipment, Quality Assurance Branch at 916-227-9709.
- Installation of crimps and terminals in size range 8 gauge and larger shall use the crimp manufacturer’s recommended heavy duty compound lever or hydraulic style die type tool or soldered. Crimping is preferred over solder.
- Wires shall be stripped with the proper tool. Wire strip lengths shall conform to the crimp terminal manufacturer’s recommendations.
2.2.2 Parts and Materials
- Metals used for and with electrical connections (studs, nuts, screws, etc.) shall be corrosion resistant (e.g. Tin, Zinc Plate, etc.)
- A connector or lug of the set screw type must not be used with a stranded conductor smaller than 10 gauge unless there is a nonrotating follower that travels with the set screw and makes pressure contact with the conductor. If a follower is not available then a nylon insulated, tin plated, double crimp style, pin terminal (wire ferrule) shall be used to terminate the wire. Trailer connectors do not apply.
- Twist-on wire connectors or insulation displacement type wire connectors shall not be used. (e.g., wire nuts, scotchlock, etc.)
- If solder is used to connect wires or terminals then the connections shall be supported to prevent flexing of the connection. Adhesive lined heat shrink tubing is an acceptable means of support. (e.g. ES 1000 by Raychem, TES by 3M)
- When soldering wires use only rosin core solder. Acid core solder is not acceptable.
- All noninsulated crimp or solder heavy duty lugs shall be sealed with adhesive lined heat shrink tubing (e.g., ES 1000 by Raychem, TES by 3M).
- Plug and receptacle connectors shall have means to support wires and limit flexing (e.g., back shells with strain relief).
- For 22 to 10 gauge wires, solderless insulated crimp terminals shall be double crimp style tin plated copper, UL listed, nylon insulated, red, blue, yellow, rated to 220Âº F. (e.g. PIDG by Amp, Avikrimp by Molex)
- For 22 to 10 gauge wires, non-insulated barrel styles shall be tin plated copper, braised seam, UL listed, rated to 300Âº F. (e.g. Solistrand by Amp, Versakrimp by Molex)
- For wires 8 gauge and larger, non-insulated crimp terminals shall be heavy duty, seamless, copper, tin plated, no inspection hole. (e.g. Heavy Duty Drawn Electrical Lug [1526xxx-2] by Amp, Eyelet Style Copper Lug Terminal [19221-0xxx] by Molex)
2.2.3 Size and Fit
- Terminals shall be matched to wire gauge sizes.
- Ring or locking spade terminals shall be used and shall have the same size ring or locking spade as the stud or screw they attach to. Quick disconnect terminals shall have the same matching size.
2.3 Protective Measures
All unmated connectors shall be protected with metal or plastic caps or otherwise suitably protected during maintenance, storage and shipment. Protective caps specified and designed for mating with specific connectors shall be used. Unmated connectors which may contain electrically "hot" circuits that may be exposed to the outside environment shall be covered with weatherproof (IP65) caps. Spring loaded, self closing, sealing, snap type covers are acceptable. Connectors on enclosed cabinet mounted equipment need not be provided with protective caps unless exposure to the outside environment is possible. Each positive terminal or stud that is energized shall have a boot, cap, cover or shield that prevents accidental short-circuiting at the terminal or stud.
2.4 Battery Terminals
- Only heavy duty ring lugs, seamless, tin plated copper (no inspection hole), or cast copper lugs, tin plated, full height, zinc plated nut and bolt, and sized to fit positive and negative posts shall be used. (e.g. Cable Maker Battery Terminals by Amp, Precision Die Cast Copper battery Lugs #19221-0xxx, #19218-00xx by Molex, Precision Die Cast Copper Battery Terminals #19218-00xx By Molex, MagnaLug Battery terminals #19221-0xxx By Molex). (Universal size 2102T by AC Terminals)
- Attach terminals with manufacturer’s approved crimping tool or solder.
- Terminals shall be sealed and the wire supported with adhesive lined heat shrink tubing. (e.g. Es 1000 by Raychem, TES by 3M)
- Plugs and receptacle connectors exposed to the outside environment shall be weatherproof (IP65), or, if they can be submerged, water tight (IP67).
- Connectors used in multiple electric circuits shall be selected to preclude mismating. Where design considerations require plug and receptacles of similar configuration in close proximity, the mating plugs and receptacles shall be suitably coded or marked to clearly indicate the mating connectors. The design of the connector shall be such that the operator is not exposed to electrical shock or burns when normal disconnect methods are used. Exposed pin contacts shall not be energized (hot) after being disconnected from the socket contacts.
- Connectors shall lock together.
- Dielectric compounds shall not be used as the primary means to seal a connector. Such compounds are considered a backup to the main seal. If a dielectric compound is used (e.g., #4 electric insulating compound by Dow Corning) it shall not detrimentally effect electrical conduction between plug and receptacle. All connectors related to trailer and truck exterior running lights, stop, tail and turn lights, etc., shall be sealed with a dielectric compound.
- Cables and separable harnesses shall be of the two-connector type. The two connectors shall be of the same number of contacts and all contacts shall be wired point-to-point; (e.g., pin 1 to pin 1, pin A to pin A, or pin 1 to pin A and up in sequence).
- Not more than one wire shall be routed through any hole in the grommet of an environmentally sealed connector.
- Clearance between terminal strips, standoffs or similar connections shall be such that no accidental contact can occur between adjacent connections when subjected to service conditions.
- Each wire lead terminating at a connection point shall have allowance for enough slack (strain relief) to minimize tensile or shear stress.
- Ring and/or locking spade terminals that are exposed to the outside environment shall be covered and sealed with a corrosion resistant film (e.g., Liquid Tape Electrical by Plastic Dip, 3M Underbody Coating, etc.)
2.6 Number of Lugs per Terminal Board
- The maximum number of lugs to be connected to any one terminal on a terminal board should be two for screw-type terminal boards. For stud type terminal boards, not more than four lugs should be connected to any one terminal of a board. Accessories such as stud connectors, straddle plates, jumpers and terminal board lugs shall be counted as lugs for this purpose.
- In no case shall the total cross sectional area of the terminated wires exceed the cross sectional area capacity of the terminal or lug. If a greater number of wires are required than those specified herein, written approval of Caltrans, Division of Equipment, Quality Assurance shall be obtained.
- Lugs connected to terminals shall be sized to fit (i.e., cutting to fit is not acceptable).