Nibco B031250 Cast Copper Adapter 3/4x3/8 C X M

Product Description

The NIBCO B031250 is a cast copper pressure fitting adapter designed to transition between a 3/4-inch copper sweat connection and a 3/8-inch male NPT threaded connection. The C x M end configuration makes it suitable for connecting copper tubing to threaded pipe or equipment fittings in a single step. Cast from copper alloy conforming to ASTM B584, this adapter is built for pressure service in potable water, hydronic heating, and general plumbing systems. Licensed plumbers and pipefitters are the primary installers. At 0.16 pounds, it is a compact, single-piece component with no separate parts to manage on the job.

This adapter is used in residential and light commercial plumbing applications where a copper tubing run must terminate at a threaded male connection. Common scenarios include connections to valves, supply stops, gauges, and equipment inlets that accept a female NPT port. The sweat end accepts standard 3/4-inch copper tubing, and the 3/8-inch MNPT end threads directly into a compatible female-threaded fitting or body. It is appropriate for new installation and retrofit work alike.

Key Features

• Cast copper construction per ASTM B584 for pressure service durability
• 3/4-inch sweat (C) inlet to 3/8-inch male NPT (MNPT) outlet in a single fitting
• Pressure fitting style rated for use in pressurized plumbing systems
• Meets ASTM B584 and ISO standards for material quality
• Compact and lightweight at 0.16 pounds for easy handling in tight spaces

Compatibility

Designed as an OEM-style replacement or new-installation pressure fitting for copper sweat-to-male-NPT adapter applications in residential and commercial plumbing systems.

Installation Notes

Installation is performed by a licensed plumber in accordance with applicable local plumbing codes and IPC guidelines. Shut off and depressurize the water supply before beginning work. The sweat end requires standard flux and solder preparation of clean, dry copper tubing before torch application. The MNPT threads should be wrapped with thread seal tape or pipe joint compound before hand-tightening and final torque to the receiving female-threaded fitting.