Omron G7SA-4A2B DC24 — Forcibly Guided Safety Relay Review

By Abdullah Zahid
15 min read
Omron G7SA-4A2B DC24 safety relay with forcibly guided contacts for machine e-stop and guard door circuits

Omron G7SA-4A2B DC24 – Forcibly Guided Safety Relay with 4 NO + 2 NC Contacts, 24 VDC Coil

Controls and safety engineers sourcing a compact, safety-certified relay for e-stop, guard door, or light curtain circuits consistently land on the Omron G7SA-4A2B DC24 — a discrete safety relay with 4 NO and 2 NC forcibly guided contacts, a 24 VDC coil, and a 6 A contact rating, certified to EN 61810-3 and EN 50205 Class A with VDE and CE support. If your safety architecture calls for multiple normally-open switching outputs alongside monitored normally-closed feedback contacts in a single slim package, this is the relay that belongs on your BOM — provided the contact mix and coil voltage match exactly what your schematic requires.

If you have already confirmed this is the right part, check current pricing and availability for the Omron G7SA-4A2B DC24 at LeadTime.ca — ships worldwide.

Who Should Buy the Omron G7SA-4A2B DC24 — and Who Shouldn't

This relay is the correct choice when all of the following are true for your application:

  • Your safety circuit requires exactly 4 NO and 2 NC forcibly guided (mechanically linked) contacts in a single body
  • Your control supply is 24 VDC — not 12 VDC, 48 VDC, or any AC voltage
  • You need EN 61810-3 / EN 50205 Class A compliance and VDE / CE certification support for machinery safety approvals
  • Your load current does not exceed the 6 A contact rating under resistive conditions, with appropriate derating for inductive loads
  • Your design uses PCB terminal mounting or a compatible P7SA / G7SA socket, and your board layout or enclosure matches this footprint
  • Ambient operating conditions fall within –40 °C to +85 °C with no icing or condensation

If you need a different contact mix — such as 2 NO + 2 NC, 3 NO + 1 NC, or 5 NO + 1 NC — other variants in the G7SA family are the correct choice. If your application requires integrated diagnostics, configurable logic, or fieldbus connectivity, a full safety controller is a better fit than any discrete relay in this series.

On this page:

What the Omron G7SA-4A2B DC24 Actually Does in a Safety Circuit

The Omron G7SA-4A2B DC24 is a discrete safety relay — not a safety controller — belonging to Omron's G7SA series of relays with forcibly guided contacts. The defining characteristic of this series is mechanical linkage between normally-open and normally-closed contact sets. When a contact welds shut due to fault conditions, the mechanical coupling prevents the opposite contact set from operating normally, making it physically impossible for both sets to be simultaneously in their energized state. This is the basis for contact position monitoring in safety architectures: the NC contacts can be used as a feedback loop to a safety controller or monitoring module, confirming that the NO contacts have actually released and the circuit is safe to re-enable.

The G7SA-4A2B DC24 provides 4 NO contacts for switching safety outputs — such as power to machine contactors or drives — and 2 NC contacts available for the feedback and monitoring path. The 24 VDC coil is energized by the safety control signal, and the 6 A contact rating handles the typical load requirements of machine safety switching at standard industrial voltages. Reinforced insulation is provided between input and output and between poles of different polarity, meeting the requirements of EN 61810-3 and EN 50205 Class A as verified by VDE certification.

This relay operates as one component within a safety function. It does not contain logic, diagnostics, timers, or any communications interface. The safety architecture around it — the safety controller, wiring methodology, monitoring logic, and validation procedures — determines the achievable safety category or performance level. The G7SA-4A2B DC24 contributes its certified contact behavior as a building block within that larger certified system.

Typical System Architecture for the G7SA-4A2B DC24

The G7SA-4A2B DC24 sits at the output switching layer of a safety circuit, positioned between the safety control logic and the load-side machine contactors or other safety-rated devices. Here is how it typically fits in the signal chain:

  • Safety input device (e-stop button, guard door switch, light curtain OSSD output, or two-hand control) feeds a signal to the upstream safety controller or monitoring module
  • Safety controller or monitoring module evaluates the input and controls the 24 VDC coil of the G7SA-4A2B DC24
  • The 4 NO contacts of the G7SA-4A2B DC24 switch power to machine contactors, motor drives, or other hazardous energy sources
  • The 2 NC contacts of the G7SA-4A2B DC24 feed back to the safety controller's monitoring input, confirming correct relay de-energization before a restart is permitted
  • Downstream machine contactors or drives control the hazardous motion, with their own auxiliary contacts optionally feeding back further into the safety loop

Applications and Industries Where the G7SA-4A2B DC24 Belongs

Machine builders and safety engineers specify the G7SA-4A2B DC24 most often in press and metal forming machinery, where e-stop and two-hand control circuits require multiple NO switching contacts plus NC feedback monitoring in a compact body. The 4 NO + 2 NC configuration is well suited to dual-channel e-stop architectures where each channel uses two NO contacts in series for the contactor loop, and the 2 NC contacts provide the restart interlock feedback signal.

Packaging line integrators and assembly automation engineers use this relay in guard door and safety gate interlock circuits, where it interfaces between a safety controller and the machine's power contactors. The reinforced insulation between input and output supports the electrical separation requirements of these circuits, and the VDE-certified EN 50205 Class A compliance simplifies CE marking documentation for machinery exported to the EU and other markets.

OEM machine tool builders frequently include the G7SA-4A2B DC24 in standard panel layouts for safety light curtain and laser scanner output interfacing. The relay's slim form factor allows multiple units to be mounted in dense panels where space is a genuine constraint. Safety retrofit projects on older machines — where a certified safety relay needs to be introduced into an existing circuit — also benefit from this relay's straightforward integration into standard PCB or socket-mounted panel architectures.

Process equipment skid builders and intralogistics/conveyor system integrators round out the typical user base, particularly where modular safety relay modules would introduce unnecessary complexity or cost for a fixed, well-understood safety function that simply needs a reliable switching component with certified contact behavior.

Application Typical Deployment
E-stop circuits on press and metal forming machinery 4 NO contacts in dual-channel contactor loop; 2 NC contacts to safety controller feedback input
Guard door and safety gate interlocking Safety controller drives 24 VDC coil; NO contacts switch machine power; NC contacts provide restart interlock
Safety light curtain and laser scanner interfacing OSSD outputs of light curtain control relay coil; NO contacts drive drive inhibit or contactor; NC contacts to monitoring loop
Two-hand control on cutting and stamping machines Two-hand module drives coil; multi-pole NO contacts provide redundant switching to press contactor
Safety relay feedback in modular safety controller architectures G7SA-4A2B DC24 acts as output expansion relay; NC contacts return to controller feedback monitoring channel
OEM panel builder standard safety module PCB-mounted or socket-mounted in standardized panel layout across multiple machine variants

Key Specifications and Variant Comparison for the G7SA-4A2B DC24

Parameter Value
Brand Omron
Model / Catalog Number G7SA-4A2B DC24
Product Type Safety relay with forcibly guided (mechanically linked) contacts
Contact Configuration 4 NO + 2 NC forcibly guided contacts
Coil Voltage 24 VDC
Contact Rating 6 A (resistive loads)
Insulation Type Reinforced insulation between input and output and between poles of different polarity
Safety Standards EN 61810-3, EN 50205 Class A
Certifications VDE, CE
Operating Temperature –40 °C to +85 °C (no icing or condensation)

Full technical specifications are available on the product page at LeadTime.ca.

The G7SA family covers several contact configurations in the same certified platform. The table below shows the key variants to cross-reference when the 4 NO + 2 NC mix is not the right fit for your circuit:

Model Contact Configuration Coil Voltage Options Contact Rating Best For
G7SA-2A2B 2 NO + 2 NC 12 VDC, 24 VDC, 48 VDC, 110 VDC 6 A Simpler circuits needing equal NO/NC split with fewer poles
G7SA-3A1B 3 NO + 1 NC 12 VDC, 24 VDC, 48 VDC, 110 VDC 6 A Circuits needing more switching outputs with a single feedback NC
G7SA-4A2B DC24 4 NO + 2 NC 24 VDC 6 A Multi-pole e-stop and dual-channel contactor switching with dual NC feedback
G7SA-3A3B 3 NO + 3 NC 12 VDC, 24 VDC, 48 VDC, 110 VDC 6 A Architectures needing equal numbers of switching and monitoring contacts
G7SA-5A1B 5 NO + 1 NC 12 VDC, 24 VDC, 48 VDC, 110 VDC 6 A High output count circuits where only one NC feedback contact is required

If the 4 NO + 2 NC configuration matches your design but the coil voltage is different from 24 VDC, confirm which coil voltage variants are available for the G7SA-4A2B before placing an order — check current availability and confirm the correct variant at LeadTime.ca.

Expert Verdict: Is the Omron G7SA-4A2B DC24 Right for Your Project?

The Omron G7SA-4A2B DC24 is the relay to specify when your safety circuit demands a 4 NO + 2 NC forcibly guided contact configuration on a 24 VDC coil in the smallest reasonable footprint, with certifications that hold up under regulatory scrutiny. Controls engineers designing e-stop and guard door circuits for CE-marked machinery will find this relay a direct fit: the EN 61810-3 and EN 50205 Class A compliance backed by VDE certification does the documentation heavy lifting, and the reinforced insulation between input, output, and poles of different polarity meets the electrical separation requirements that safety circuit design demands. OEM panel builders who standardize on Omron safety components will appreciate that the G7SA-4A2B DC24 integrates cleanly into the same socket and PCB ecosystem as other G7SA variants, making it straightforward to accommodate across multiple machine platforms.

Where this relay reaches its natural limits is in applications that need more than a discrete switching component. If your safety function requires configurable logic, automatic or manual monitored reset built into the safety device, timer functions, fieldbus diagnostics, or detailed fault reporting, a dedicated safety relay module or safety controller is the correct solution — the G7SA-4A2B DC24 will not provide those capabilities regardless of how it is wired. Similarly, if your circuit needs a different contact mix — 2 NO + 2 NC for a simpler interlock, or 5 NO + 1 NC for a high-output architecture — the G7SA-3A1B, G7SA-2A2B, G7SA-3A3B, or G7SA-5A1B are the parts to evaluate. The 6 A contact rating is appropriate for most machine safety switching at standard industrial voltages, but loads that push or exceed that limit under inductive conditions require careful derating analysis before this relay is finalized on the BOM.

From a procurement standpoint, the G7SA-4A2B DC24 is a well-established part in a current product family, and it is generally available through authorized distributors serving North America and global markets. That said, coil-voltage-specific variants of safety relays are not always held in equal stock quantities, and lead times when a specific variant is out of stock can stretch into multiple weeks — a real risk for machines on a tight build schedule. Ordering through a specialist distributor who can verify your exact part number against your schematic, flag close-but-wrong G7SA variants before they reach your receiving dock, and give you a realistic stock and lead-time picture before you commit is worth the call. View current pricing and stock status for the G7SA-4A2B DC24 at LeadTime.ca before finalizing your order quantity.

For volume pricing or to confirm lead time before committing to a build, contact the LeadTime.ca team directly — we ship worldwide.

What Engineers Need to Know Before Ordering the Omron G7SA-4A2B DC24

Community discussion specific to the G7SA-4A2B DC24 model is limited across forums including r/PLC, r/automation, PLCTalk, PLCS.net, MrPLC, and distributor Q&A sections — most conversation happens at the G7SA family level or the broader Omron safety relay level. What does surface consistently is worth paying attention to, because the mistakes that appear in these discussions are repeatable and avoidable with the right pre-order discipline.

At the family level, engineers describe Omron safety relays including the G7SA series as reliable and straightforward to integrate into standard safety circuits. The slim form factor draws recurring positive mention from panel builders working in space-constrained enclosures, and the availability of matching sockets and terminal options is cited as a genuine convenience advantage for wiring and future servicing. These are not dramatic endorsements, but the absence of persistent complaints about the relay's fundamental behavior is meaningful in a product category where a hidden flaw would surface quickly in safety-critical applications.

The problems that do appear in community discussions are almost entirely selection and ordering errors rather than product failures. Confusing the G7SA-4A2B DC24 with other G7SA contact mix variants — particularly the G7SA-2A2B — is the most frequently cited ordering mistake, often discovered only after the relay arrives and the NC feedback contacts do not match the schematic. Ordering the wrong coil voltage because the BOM did not clearly specify the voltage suffix is the second most common error. A third, less obvious trap is confusing the G7SA series with other Omron relay families such as the G7S when using automated cross-reference tools, which can result in a footprint or pinout mismatch that is not caught until panel assembly. When direct community feedback on a specific part is sparse, the practical guidance is to work with a distributor who can catch these errors at the order stage rather than at the machine. The checklist below is the fastest way to verify your selection before committing.

Wiring and Installation Overview for the Omron G7SA-4A2B DC24

  • Identify coil terminals and contact terminals using the Omron datasheet pinout or the compatible socket wiring diagram before any connections are made; verify polarity requirements for the 24 VDC coil supply
  • Mount the relay on the PCB or fully seat it in the compatible P7SA / G7SA socket, confirming correct orientation — a misaligned relay in a socket can damage both the relay and the socket body
  • Route the 4 NO contacts to the machine contactors, drives, or other safety-rated switching loads, and connect the 2 NC contacts to the feedback monitoring input of the upstream safety controller or monitoring module
  • Install external overcurrent and short-circuit protection (fuses or breakers sized to the circuit) upstream of the relay contacts — the G7SA-4A2B DC24 does not contain an integrated protective device
  • Before placing the circuit into service, perform continuity verification on all NO and NC contacts with the coil both de-energized and energized, then complete the full safety function validation test — e-stop actuation, feedback loop confirmation, and restart interlock — as required by your safety plan and the applicable machine standard

Wrong-Part Prevention Checklist Before You Order

The most expensive mistake with this relay is ordering the wrong variant. Work through this checklist before placing any order for the Omron G7SA-4A2B DC24:

  1. Confirm you need 4 NO and 2 NC forcibly guided contacts (not 2NO+2NC or 3NO+3NC).
  2. Verify control voltage is 24 VDC; do not mix it with 12 VDC or 48 VDC variants.
  3. Check that PCB terminal style and pinout match your board layout or selected socket type.
  4. Ensure 6 A contact rating and insulation level are sufficient for the load type and safety category.
  5. Confirm approvals (EN 61810-3 / EN 50205, VDE, CE) meet your machine's regulatory requirements.
  6. Validate ambient temperature range and environment (–40 to +85 °C, no icing/condensation) are within your application limits.

If any item on this checklist raises a doubt, do not guess — contact the LeadTime.ca team to confirm the correct part number before your order is placed. We ship worldwide and can validate your selection against your application details.

Frequently Asked Questions

Is the Omron G7SA-4A2B DC24 a safety relay on its own, or does it still require a safety controller?

The G7SA-4A2B DC24 is a certified safety relay component — it provides forcibly guided contacts compliant with EN 61810-3 and EN 50205 Class A — but it is not a complete safety control system. It functions as a switching and feedback element within a safety function that must be designed around a safety architecture, including appropriate safety controllers, monitoring logic, and validated wiring. The relay contributes its certified contact behavior to that architecture; it does not replace the controller or monitoring module.

How many safety channels can be implemented with a single G7SA-4A2B DC24?

With 4 NO and 2 NC contacts available, a single G7SA-4A2B DC24 can support dual-channel e-stop or guard door architectures where each channel uses two NO contacts in series for the contactor switching loop, leaving the 2 NC contacts for feedback monitoring. The exact number of channels and the safety category or performance level achievable depends on the overall circuit design and the safety controller used in conjunction with the relay — not the relay alone.

Can the G7SA-4A2B DC24 directly replace another manufacturer's forcibly guided relay without modifying the PCB or socket?

Not automatically. While the contact configuration and certifications may align with relays from other manufacturers, pinout assignments, body dimensions, and socket compatibility vary between brands and even between Omron relay families. Always compare the exact datasheet pinout and mechanical dimensions of both the existing relay and the G7SA-4A2B DC24 before assuming a drop-in replacement. If you are replacing a relay from a different Omron family such as the G7S, the same caution applies — family names are similar but footprints may differ.

What is the practical difference between the G7SA-4A2B and the G7SA-2A2B or G7SA-5A1B in a real safety circuit?

The difference is purely in how many NO and NC contacts are available for your circuit design. The G7SA-2A2B offers 2 NO and 2 NC contacts, which suits simpler single-channel or lower-output architectures. The G7SA-5A1B provides 5 NO and only 1 NC, which suits circuits needing maximum switching outputs with a single feedback path. The G7SA-4A2B DC24 sits between these options at 4 NO and 2 NC, making it the preferred choice for dual-channel contactor architectures with dual NC feedback monitoring. All variants share the same 6 A contact rating and EN 50205 Class A compliance.

What approvals does the Omron G7SA-4A2B DC24 carry for CE marking of machinery?

The G7SA-4A2B DC24 is certified by VDE and complies with EN 61810-3 and EN 50205 Class A, which covers the requirements for safety relays with forcibly guided contacts used in machine safety circuits. CE marking of the final machine remains the responsibility of the machine builder, who must demonstrate that the complete safety function — including this relay — meets the applicable machinery directive and safety standards requirements through proper design and validation documentation.

Why Order the Omron G7SA-4A2B DC24 from LeadTime.ca

  • LeadTime.ca ships worldwide — whether you are building machines in Canada, the US, or internationally, we fulfill orders globally
  • We specialize in industrial automation and safety components, which means we can cross-reference G7SA variants and catch coil voltage or contact mix errors before the wrong part ships
  • Current pricing and stock status are live on the product page — no guessing on availability before you commit to a build schedule
  • Volume pricing and lead-time confirmation are available on request for OEM and MRO buyers — contact us directly before placing large or time-critical orders
  • Hard-to-find or short-lead-time parts are a core part of what we do — if stock is tight, we will tell you and help you find the fastest path to the part you need

Omron G7SA-4A2B DC24 — At-a-Glance Summary

  • Safety relay with forcibly guided (mechanically linked) contacts — 4 NO + 2 NC configuration in a single compact body
  • 24 VDC coil voltage — confirm this matches your control supply before ordering
  • 6 A contact rating for resistive loads — apply appropriate derating for inductive loads
  • Certified to EN 61810-3 and EN 50205 Class A with VDE and CE certification support
  • Reinforced insulation between input and output and between poles of different polarity
  • Operating temperature range: –40 °C to +85 °C (no icing or condensation)
  • PCB terminal mounting; compatible with P7SA / G7SA socket types for panel wiring
  • Part of the Omron G7SA family — variants available in 2A2B, 3A1B, 3A3B, and 5A1B contact configurations with multiple coil voltage options
  • Discrete relay component — not a safety controller; must be used within a properly designed and validated safety architecture
  • Typical applications: e-stop circuits, guard door interlocking, light curtain interfacing, two-hand control on press machinery, OEM panel safety circuits

You may also be interested in: