Southwire P-18 Mast Clamp Wire Holder 1-1/4 to 3 in

Product Description

The SOUTHWIRE P-18 is a mast clamp wire holder designed to support insulated service entrance conductors on residential and light commercial electrical installations. It secures conduit masts ranging from 1-1/4 to 3 inches in diameter, providing a stable, code-appropriate anchor point for overhead service drops. Licensed electricians and electrical contractors install this type of fitting during new service installations or service upgrades. The clamp is manufactured in the United States and carries a one-year limited warranty.

The P-18 is used in exterior service entrance applications where an insulated support point is required between the utility drop and the meter base or service panel. It mounts to the building structure and holds the service mast securely in place, reducing mechanical stress on the conduit and conductors during wind load or ice loading conditions. This fitting is appropriate for residential services as well as small commercial structures where overhead utility connections are used.

Key Features

• Accommodates mast diameters from 1-1/4 to 3 inches for broad conduit compatibility
• Insulated support design protects conductors at the clamp contact point
• Manufactured in the United States
• One-year limited warranty
• Also referenced as Topaz 999 and Madison P-18

Compatibility

Designed as an OEM-style replacement and cross-compatible fitting referenced under Topaz 999 and Madison P-18 part numbers. Fits conduit masts from 1-1/4 to 3 inches in diameter for standard service entrance installations.

Installation Notes

Installation should be performed by a licensed electrician in accordance with NEC requirements for service entrance equipment. Coordinate with the local utility and authority having jurisdiction before working on or near the service drop. De-energize all circuits within the scope of work before handling service entrance conductors. Verify that the mounting surface is structurally sound and capable of supporting the mast and any anticipated mechanical loading.

Technical Specifications

• Mast Diameter Range: 1-1/4 to 3 inches
• Length: 19.8 inches
• Height: 6.2 inches
• Width: 11.8 inches
• Weight: 29.05 pounds
• Warranty: One Year Limited
• Country of Origin: United States

Standard Information

• Brand: SOUTHWIRE
• Manufacturer Part Number: P-18