The various types and classes of connectors are intended for use as follows:

a. Class C connectors are intended for external interconnection use on vans, shelters, trailers, buildings and heavy duty (rough service) applications. They are not for primary power distribution.

b. Class J connectors are intended for use only where class C connectors can be used but where a wire support grommet is necessary.

c. Class L connectors are intended for power connections in the current range from 40 to 200 amperes where heavy duty, waterproof and arc quenching ability are required and are to be used only with heavy-duty jacketed cables specified on the applicable insert standard. Connectors with conductive finishes are for AC circuits /grounding assemblies. Connectors with a non-conductive finish are for DC circuits / non-grounding assemblies.

d. Class R connectors are intended for use as general purpose heavy-duty connectors where pressurization and arc quenching ability are not required. The connectors can be made weatherproof when the accessory sealing adapter is attached. They are not for primary power distribution. 

Use of alternate insert positions. When connectors of the same size and arrangement are installed sufficiently adjacent to one another to provide a danger of mating plug with the wrong receptacle, it is intended that alternate insert positions should be employed. Alternate insert positions are also used in the class L connectors to differentiate between the various power frequencies being used. 

Wire sizes to be used with contacts. It is intended that the wire attached to each connector contact should be of the AWG size (or smaller diameter), corresponding to the contact size number. For example, it is intended that an AWG size 12 wire be soldered to at least a size 12 contact; and an AWG size 6 wire should be soldered or crimped if applicable to a size 4 or size 6 contact. SAE-AS39029/112 contact bushings should be used with class L contacts if the wire AWG is smaller than the wire barrel size. 

Packaging and storage, cadmium plated connectors: See SAE-AMS-QQ-P-416 for packaging limitations for cadmium plated products. Users are advised that cadmium plated parts should not be packed in non-ventilated containers or in direct contact with wood or cardboard, especially under conditions of high humidity or moisture, due to a corrosive reaction that can occur between the cadmium plating and organic acids that form under these conditions.