Phoenix Contact ST 4-MT Knife-Disconnect Terminal Block

Technical Overview

400V, 20A knife-disconnect terminal block with spring-cage connection for 0.08-6mm² conductors. DIN rail mountable, -60°C to 110°C operating temp.

Key Features

Spring-cage connection enables one-handed, tool-free wiring.
Knife disconnection allows for convenient circuit isolation.
Accommodates a wide range of conductor cross-sections from 0.08 mm² to 6 mm².
Spring-loaded contact elements ensure reliable vibration resistance, verified by DIN EN 50155 testing.
Compatible with the CLIPLINE complete system for standardized bridging, marking, and testing accessories.
Designed for use in railway applications, machine building, and plant engineering.

Technical Specification Matrix

Parameter	Value
Nominal Voltage	400 V
Nominal Current	20 A
Rated Surge Voltage	6 kV
Connection Method	Spring-cage connection
Rated Cross Section	4 mm²
Conductor Cross-section (rigid)	0.08 mm² - 6 mm²
Conductor Cross-section (flexible)	0.08 mm² - 4 mm²
Conductor Cross-section (flexible, ultrasound-compressed)	0.34 mm² - 6 mm²
Stripping Length	8 mm - 10 mm
Number of Levels	1
Number of Connections	2
Mounting Type	DIN rail NS 35/7,5, NS 35/15
Color	Gray (RAL 7042)
Insulating Material	PA
Flammability Rating	UL 94 V0
Operating Temperature	-60°C to 110°C
Physical Weight (kg)	0.01
Dimensions L x W x H (cm)	6.15 x 0.62 x 3.65

Industrial Applications

1. Control Panel Wiring in Industrial Machinery

This terminal block is ideal for safely isolating individual circuits within industrial control panels in manufacturing or process machinery. The knife disconnect feature allows for easy and secure circuit separation for maintenance or troubleshooting without disrupting other connections.

Problem Solved

Provides a reliable and easily maintainable method for disconnecting power to specific components or sub-circuits within complex industrial machinery, improving safety during servicing and reducing downtime.

400V20ASpring-cageKnife disconnectDIN railIndustrial controlCircuit isolation

2. Railway Signaling and Control Systems

The ST 4-MT is well-suited for use in railway applications where robust and vibration-resistant connections are critical for signaling, trackside equipment, and onboard control systems. Its wide operating temperature range of -60°C to 110°C and DIN EN 50155 vibration resistance ensure reliable operation in harsh railway environments.

Problem Solved

Ensures secure and stable electrical connections in environments subject to constant vibration and extreme temperature fluctuations, which is crucial for the safety and operational integrity of railway infrastructure.

400V20ADIN EN 50155Vibration resistanceRailway applications-60°C to 110°CSpring-cage

3. Power Distribution in HVAC Systems

This terminal block is suitable for power and control circuit distribution within large commercial or industrial HVAC (Heating, Ventilation, and Air Conditioning) systems. The spring-cage connection provides fast, tool-free wiring, and the disconnect function simplifies system commissioning and fault isolation.

Problem Solved

Facilitates efficient and reliable power distribution with easy circuit isolation for maintenance or component replacement in demanding HVAC installations, offering quick installation and robust connections.

400V20ASpring-cageKnife disconnectPower distributionHVACQuick wiring