ASTM B787/B787M is the ASTM standard that covers 19 wire combination unilay-stranded copper conductors intended for subsequent insulation. It provides a technical basis for describing conductor construction before insulation is applied, helping buyers, manufacturers, and quality teams align on the expected product form. For wire and cable specifications, this standard matters because it supports consistent procurement, evaluation, and communication around conductor design and compliance.

Overview of ASTM B787/B787M

The official title, Standard Specification for 19 Wire Combination Unilay-Stranded Copper Conductors for Subsequent Insulation, indicates a focused specification for copper conductors with a defined stranded construction. ASTM B787/B787M is used as a reference point for product requirements that apply before insulation is added, which can help ensure the conductor is suitable for later cable or wire processing. As an ASTM standard, it supports uniform expectations for technical description, acceptance, and manufacturing control.

Common use cases of ASTM B787/B787M

This specification is commonly used when copper conductors are being selected or verified for insulated wire and cable products. It is relevant in manufacturing workflows where the stranded conductor must be identified, evaluated, and prepared for insulation processes. ASTM B787/B787M may also be used by purchasing teams, inspectors, and engineers who need a clear material and construction reference during product specification, comparison, or incoming quality review.

Benefits of using ASTM B787/B787M

Using ASTM B787/B787M helps create a shared technical standard for conductor construction, which can improve consistency across sourcing, production, and verification steps. It supports clearer compliance checks and reduces ambiguity when comparing products from different suppliers. For quality control and product evaluation, the specification can help streamline acceptance decisions and reduce the risk of ordering conductors that do not match the intended construction for later insulation.

• Defined copper conductor construction
• Supports insulated wire and cable preparation
• Useful for procurement and specification review
• Helps standardize quality control checks