Best Two Hand Control Safety Relay Systems for Industrial Use

Two-hand safety relays are essential for ensuring operator safety in machine guarding and automation. These devices require simultaneous button presses to start a machine, preventing accidental operation and reducing the risk of injury. This guide reviews top-rated two-hand safety relay options, highlighting voltage compatibility, contact configurations, and system integration to help you choose reliable equipment for American industrial setups.

Product	Brand	Voltage	Enabling Contacts	Link
Siemens 3TK28 34-2AB20	SIEMENS	24 VAC	2 NO	Amazon
Siemens 3TK28 34-1AJ20	SIEMENS	115 VAC	2 NO	Amazon
Siemens 3TK28 34-1AB20	SIEMENS	24 VAC	2 NO	Amazon
SICK RLY3-HAND100	Sick	24 VDC	2 Enabling Paths	Amazon
PILZ 750126 (s6.1)	PILZ	24 VDC	3 NO / 1 NC / 1 SC	Amazon

Selecting the right two-hand safety relay involves considering voltage compatibility, contact configuration, diagnostics, and mounting options. below is a concise overview of key capabilities across the top picks to help you compare at a glance.

Siemens 3TK28 Series Two-Hand Safety Relays

The Siemens 3TK28 family is designed for press safety and two-hand control, with solid durability and straightforward wiring. The 34-2AB20 model operates at 24 VAC and provides two normally open enabling contacts, making it suitable for standard control circuits in small to mid-size automation lines. Its press control unit format emphasizes quick integration with guard interlocks and safety doors, ensuring both hands must be engaged to operate the machine. This variant is well-suited for low-voltage control schemes common in discrete manufacturing environments.

Key strengths include compatibility with common 24 VAC control systems, clear two-hand logic, and robust mechanical design. When installing, ensure proper terminal connections and secure mounting to minimize strain on wiring. For facilities already standardized on Siemens components, these relays offer straightforward replacement and system coherence.

Siemens 3TK28 34-1AJ20 Two-Hand Safety Relay

This variant operates at 115 VAC and features two NO enabling contacts. The higher voltage option makes it a strong candidate for machinery that requires line-level control signals or where relays are integrated with higher-powered actuators. The 45 mm width keeps it compact for control cabinets with limited space, while keeping the Siemens reliability and diagnostic clarity that industrial users expect. It is particularly suitable for equipment designed around standard 115 VAC safety circuits.

Considerations include ensuring compatibility with existing 115 VAC control rails and confirming that wiring meets local electrical codes. The product’s two-hand operation principle aligns with common safety standards, providing a predictable and verifiable safety mechanism in production lines that demand higher voltage operation without sacrificing operator protection.

Siemens 3TK28 34-1AB20 Two-Hand Safety Relay

The 34-1AB20 version brings 24 VAC operation with two normally open contacts and the familiar Siemens build quality. It is a solid choice for new installations or upgrades to an existing 24 VAC control network. The compact 45 mm width allows for flexible panel layouts, especially in multi-station presses or packaging lines that require reliable two-hand control without sprawling hardware.Installation considerations include ensuring proper enclosure protection and routing of control wiring to minimize interference from nearby motors or drives.

For end-users, this model balances accessibility, safety compliance, and ease of maintenance. The two-hand design supports standard safety PLC integration and diagnostic checks, helping maintenance teams quickly verify that both hands must be engaged to activate the process.

SICK RLY3-HAND100 Two-Hand Safety Relay

The SICK RLY3-HAND100 provides a robust two-hand safety solution with a dedicated application diagnostic output and an external device monitoring input. This configuration supports more complex safety circuits where additional monitoring or remote signaling is required. With 24 VDC operation and two enabling current paths, it offers clear visibility into fault states, enabling rapid troubleshooting and reduced downtime. It is well-suited for automated lines that require integrated safety monitoring and precise fault reporting.

Users should plan for DC control environments and ensure compatible power supply rails. The diagnostic outputs can be leveraged by safety PLCs or maintenance panels to provide actionable fault data during operation and testing.

PILZ 750126 (s6.1) Safety Relay, 2 Channel

The PILZ 750126 offers a two-hand control solution with a feature set suitable for more demanding safety requirements. It presents 2 channels with 3 NO/1 NC/1 SC outputs, delivering a versatile configuration for multi-point guarding, reset circuits, and interlocked operations. The module’s DIN rail mounting and compact footprint simplify installation in standard control panels. As with other rigid safety relays, ensure that wiring practices comply with electrical codes and that the device is integrated into a properly validated safety system with appropriate monitoring.

For facilities using PILZ components, this model provides a cohesive option with strong downloadable documentation and compatibility with existing safety-programmable logic controllers. Its varied output configuration supports nuanced interlock strategies and selectable safety pathways to suit complex manufacturing cells.

Buying Guide: Key Purchase Considerations

• Voltage compatibility: Choose a relay that matches your control system voltage (24 VAC/DC or 115 VAC) and any power supply constraints in your panel.
• Contact configuration: Ensure the number and type of enabling contacts align with your safety logic. Two NO contacts are common, but some installations may benefit from additional NC or SC paths.
• Diagnostics and monitoring: Some models offer fault diagnostics, diagnostic outputs, or external monitoring inputs. This can reduce downtime and simplify maintenance.
• Mounting and footprint: Check enclosure space and mounting method (DIN rail, screw terminals, etc.). A compact width (around 45 mm) helps in crowded panels.
• System compatibility: If your plant already uses Siemens, PILZ, or SICK components, sticking to the same family can simplify wiring diagrams and spare parts management.
• Safety standards and approvals: Verify compliance with relevant standards for your region and application, such as ISO 13849-1 or IEC 62061, particularly in high-risk environments.
• Maintenance and serviceability: Consider availability of replacement parts, ease of testing the two-hand control, and whether the device supports straightforward PLC integration.
• Reliability under continuous operation: Look for devices with proven long-term reliability in industrial settings, especially in environments with dust, moisture, or temperature variation.

In conclusion, selecting the right two-hand safety relay involves matching voltage, contact configuration, and diagnostic capabilities to your specific control architecture. The Siemens, SICK, and PILZ options highlighted here cover a spectrum from compact 24 VAC solutions to higher-voltage variants and more feature-rich configurations, enabling robust safety control across diverse American manufacturing environments.