Section 9 - Purchasing Guidelines

Material choices and construction complexity are the basic considerations in purchasing high-temperature insulated wire. But, other factors can increase costs unnecessarily due to "over-specification." The following guidelines should be part of any wire selection checklist:

Voltage Specification: Circuit designers sometimes specify a 600 V wire construction for a 300 V application. This error can drive up wire costs 30% or more.

Conductor: Standard conductor options should be considered first. Unnecessary specifications can raise costs, without significant gain in performance. However, special performance conductors are considered when the added cost can be justified based on improved assembly, solderability, etc.

Standards Interpretation: Agency approval requirements are important considerations. Specification of both UL and CSA Listings can lead to added costs, for example. For products marketed throughout North America, the CSA standards typically are used because they encompass the UL requirements.

Colors: Color specification can affect wire price. For greatest economy, specification should be made from 10 standard opaque colors, available as solids, tracers, hash marks or stripes. The following marking guidelines apply:

• Fluorocarbon FEP and PFA constructions - solid colors or hash marks
• Braidless silicone - hash marks or stripes
• PVC - solid colors, hash marks or stripes
• Braided wire - solid colors or tracers

Packaging: Radix has standardized its bulk wire packaging on universal 12-in. wide reels, with three flange and barrel diameter options (22-in. flange with 8-in. barrel, 15-in. flange with 6-in. barrel, and 11-in. flange with 6-in. barrel). To keep costs down, special handling and packaging requirements, such as smaller spools, should be avoided, if possible.

Order quantity: Set-ups of equipment are a major part of the costs of insulated wire products. To achieve savings, wire orders should take into account long-term needs. This means carefully projecting requirements as far into the future as is reasonable. As a rule of thumb, four to six weeks are required to schedule and set-up equipment, to assemble materials and to package the wire for shipping.

Standard products: To maximize cost-effectiveness in purchasing high-temperature lead wires, standard products should be specified unless none are suitable for a particular application. When a custom wire design is needed, working closely with the wire supplier will ensure that design specifications are met without adding excess cost.

Purchasing consolidations: The advantages of wire standardization and consolidated purchasing are more likely to be realized when purchasing agents work closely with their product designers and production managers, particularly during early stages of product design and production planning.