Connectors and fittings requiring high mechanical properties are cast from aluminum alloy 356. Sand cast 356 is heat treated to the T6 temper, and permanent mold castings are heat treated to the T61 temper. The 356 alloy is a 7 per cent silicon-0.3 per cent magnesium-aluminum alloy. The alloy is not susceptible to stress corrosion or season cracking. Its volume conductivity is approximately 39 per cent, I.A.C.S.

Cast compression connectors requiring a soft high conductivity aluminum are supplied from 99 plus per cent pure aluminum. Other aluminum compression connectors are made from commercially pure high conductivity wrought aluminum.

Select type of connector from those listed below and follow the indicated procedure.

1. For aluminum to aluminum connections and aluminum to copper connections without a copper lined contact.
   • Vigorously clean all contact surfaces of the connector and conductor with a stiff stainless steel wire brush to remove oxides. A typically bright aluminum surface should be obtained. Do Not Wire Brush Plated Contact Surfaces.
   • Immediately coat these contact areas with a liberal amount of contact sealant.
   • Install fitting with bolts finger tight. If a generous bead of compound does not appear, remove the conductor and add more sealant.
   • Alternately (criss-cross) and evenly tighten bolts with a torque wrench to the values shown on catalog page 6.
   • Excess sealant squeezed out of joint can be left as is or can be lightly smoothed along contact line.
   • All excess sealant must be removed from EHV Connectors and entirely from cable insulation.
2. For Aluminum connectors with a copper liner to copper connection.
   • For maximum corrosion protection of the joint, the steps given in A-1 to A-5 should be followed.

1. For cable connections:
   • Remove all oil, grease and water in vicinity of surfaces to be welded. Vigorously clean the conductor and connector welding areas with a stainless steel brush.
   • Slide the conductor into the weldment cavity until it is within 1/8" to 3/16" of the rear of the welding barrel.
   • Prior to welding the connection, a test bead should be made upon an aluminum casting to test the weld settings. (See our catalog Section G - Substation Connectors for detailed welding procedure).
   • Begin welding by "burning into" the inner wall of the casting and proceeding toward the conductor center. Wire brush the original weld if more than one weld pass is required.
2. For tubular connections:
   • Remove all oil, grease and water in vicinity of surfaces to be welded. Vigorously clean the conductor and connector welding areas with a stainless steel brush.
   • Align the tubular bus and connector groove. Begin welding by "burning into" the inner wall of the casting and proceeding toward the conductor center. Wire brush the original weld if more than one weld pass is required.
   • Prior to welding the connection, a test bead should be made upon an aluminum casting to test the weld settings. (See our catalog Section G - Substation Connectors for detailed welding procedure).
   • Due to the manufacturing tolerances on aluminum tubular bus, it is recommended that the tube be positioned in the weldment cavity and tack welded before starting final weld.
3. For welded connectors with a copper lined contact:
   • Firmly bolt the copper lined contact section of connector to the mating contact surface or to a suitable heat sink prior to welding. This prevents damage to the bonded liner.
   • Weld the aluminum connection in accordance with steps A or B above. If a heat sink is used, allow connector to cool before removing. The connector may be cooled by quenching in water.

• Vigorously clean the conductor contact area with a stainless steel brush. Do not attempt to clean connector barrel. It is not necessary to apply sealant to the conductor. All connectors will have sealant applied at the factory.
• Fully insert the conductor into the barrel and crimp. Crimping should begin nearest the center of sleeve type connectors. For closed barrel type connectors crimping should begin at the end and work toward the open end. Excess sealant squeezed out of the joint may be smoothed out around the mouth of the barrel. All excess sealant must be removed from EHV Connectors or any cable insulation.

Connectors with contact sealant - Aluminum connectors can be used for making aluminum to copper connections if the proper installation care is observed. This includes the use of a sealant in accordance with practices outlined above. Use of a sealant protects the connection from oxide formation and electrolytic corrosion for as long as it remains present in the connection completely coating the surfaces and sealing out moisture.

Added protection in addition to sealants is available. Aluminum distribution connectors can be supplied with plating or with copper lined contacts.

Bi-Metallic Transition Plates - Aluminum to copper connections between flat NEMA drilled tongues and bars can be made using transition plates (Type TP). These plates are formed from sheets of 80% aluminum 20% copper which are molecularly bonded together. Best results are obtained by using contact sealant. Always position the aluminum conductor above the copper conductor.

Tin Plating - Tin plating can be furnished on certain connectors by adding suffix "-GP" to the catalog number, aluminum distribution.

Hardware - Anodized Aluminum Clamping Bolts are standard with most Aluminum Power Connectors and may be supplied at extra cost with other connectors. The bolts are fabricated 2024-T4 aluminum and are anodized. After anodizing, the coating is sealed with a dichromate solution which imparts a yellow-green finish.

Standard nuts furnished on aluminum bolts are 6061 T6 dry waxed coated.

Insulator attachment hardware for bus supports is galvanized steel.