Steel Drain Stopper & Test Plug – Zinc Plated (Expandable)

Product Name

Steel Drain Stopper & Test Plug – Zinc Plated (Expandable)

Overview

This steel drain stopper and test plug is a robust, centre-locking mechanical pipe bung designed for both sealing drainage systems and carrying out air or water pressure tests. Manufactured from high-quality zinc-plated steel, it combines strength, durability, and corrosion resistance, proven to withstand a 90-hour salt spray test. The expandable rubber sealing ring is activated via a central locking nut and thrust washers, creating a secure, leak-proof seal against pipe walls. With a removable top cap, it is fully compatible with standard air testing kits, making it a cost-effective alternative to premium brands such as Horobin for professional drainage testing.

Key Features & Benefits

• Dual functionality supports both permanent pipe sealing and air or water pressure testing.
• Centre locking mechanism expands the rubber seal evenly for a tight, reliable fit.
• Manufactured from zinc-plated steel for superior strength and long service life.
• Corrosion resistant to 90 hours salt spray testing for demanding site environments.
• Removable top cap allows air test compatibility via 1/2" or 1" connections.
• Designed to withstand defined back pressures depending on pipe diameter.
• Cost-effective alternative to premium drain test plugs without compromising performance.

Installation & Applications

Insert the drain stopper into the pipe and tighten the central locking nut to expand the rubber sealing ring against the internal pipe wall. Suitable for blocking drains, carrying out air or water pressure tests, and isolating sections of drainage during maintenance. Commonly used in construction, groundworks, utilities, and plumbing applications. Always ensure the maximum allowable back pressure for the selected size is not exceeded.

Who Is This For?

• Drainage engineers carrying out air or water pressure testing.
• Groundworkers and contractors sealing pipes during construction phases.
• Utilities teams isolating pipework for maintenance or inspection.
• Procurement teams sourcing steel drain test plugs for site use.

Competitive Advantages

Combining the economy of price with the strength of steel, this mechanical drain plug offers reliable sealing and testing performance across a wide size range. Its air test compatibility, corrosion resistance, and clearly defined back pressure ratings make it a trusted, professional-grade alternative to higher-priced branded solutions.

Why CMT Group?

CMT Group supplies site-proven drainage and testing solutions with clear specifications to support confident trade purchasing.

• UK trade supplier for drainage, testing, and site safety products.
• Clear technical guidance to support correct product selection.
• Bulk-friendly availability for contractors and utilities teams.

Frequently Asked Questions

What is a drain test plug used for? It is used to block pipes and carry out air or water pressure tests on drainage systems during installation or maintenance.

Is this plug compatible with air testing kits? Yes. It is air test compatible via removable 1/2" or 1" top caps, depending on size.

How does the centre locking mechanism work? Tightening the central locking nut compresses the thrust washers, expanding the rubber seal to grip the pipe wall securely.

What back pressure can it withstand? Back pressure ratings vary by size, ranging from up to 30 p.s.i for smaller diameters down to 5 p.s.i for larger sizes. Always check the pressure table before use.

What pipe sizes are available? Available sizes range from 75mm (3") up to 450mm (18"), covering standard UK drainage pipe diameters.

Specifications Tables

Product Name	Steel Drain Stopper & Test Plug – Zinc Plated (Expandable)
Product Code	DS-1 / SE050001–SE050010 (size dependent)
Material	Zinc-plated steel with rubber expansion seal
Mechanism	Centre locking mechanical expansion
Corrosion Resistance	90 hours salt spray tested
Pipe Size Range	75mm to 450mm internal diameter
Air Test Compatibility	Yes – via removable 1/2" or 1" top caps

 

Product Code	Pipe Size	Fits Internal Diameter	Top Cap Size	Max Back Pressure
SE050003	75mm (3")	73–85mm	1/2"	20 p.s.i
SE050001	100mm (4")	94–108mm	1/2"	10 p.s.i
SE050004	125mm (5")	124–139mm	1/2"	10 p.s.i
SE050002	150mm (6")	150–160mm	1/2"	10 p.s.i
SE050005	200mm (8")	195–215mm	1"	7 p.s.i
SE050006	225mm (9")	210–230mm	1"	7 p.s.i
SE050007	250mm (10")	245–260mm	1"	7 p.s.i
SE050008	300mm (12")	296–320mm	1"	7 p.s.i
SE050010	450mm (18")	448–495mm	1"	5 p.s.i