Here's the thing about ordering relays for an industrial communication setup: you can stare at datasheets for hours, and still get it wrong. I know because I've done it. Twice.
In September 2022, I spec'd a Corp 8110 for a critical Omron PLC output module. Looked fine on paper. Cost me $890 in rework and a 1-week delay when the relay chattered under load. The Omron G2RL I swapped in? Worked flawlessly.
But here's the catch—that same G2RL would have been wrong for the next project. And that's what this comparison is about. Not which relay is 'better,' but which one fits your specific Omron comms application.
We're going to look at three dimensions: power handling, switching noise immunity (critical for data lines), and physical fit in a control cabinet. By the end, you'll know exactly when to grab a G2RL off the shelf versus when only the Corp 8110 (or its equivalent) will do.
I'll keep the theory to a minimum. What I'm sharing is what I learned the hard way—on a $3,200 order where every single relay had the issue.
Dimension 1: Power Handling & Contact Rating
This is where my first mistake happened. I assumed 'industrial relay' meant 'tough enough for anything.' It doesn't.
Omron G2RL: The Medium-Duty Specialist
The G2RL is Omron's general-purpose power relay. It's small, reliable, and handles moderate loads.
- Contact rating: Typically 8A to 16A at 250VAC (depending on the specific variant—verify current specs at omron.com).
- Coil power: Around 250mW to 400mW. Low enough for most PLC outputs.
- Life expectancy: ~100,000 electrical operations at rated load (source: Omron G2RL datasheet).
My experience: I've used the G2RL in over a dozen Omron PLC cabinets for applications like motor starter interlocking, signal lamp control, and small valve actuation. On a 1,200-piece production run in Q1 2024, we had zero field failures. Solid performer.
Corp 8110: The Heavy Lifter
The Corp 8110 (and its equivalents from other manufacturers) is a different beast. It's a 'high inrush' relay designed for loads that draw a big current spike on startup.
- Contact rating: Typically 20A to 30A at 250VAC—significantly higher than the G2RL.
- Coil power: Can be double or triple the G2RL (think 900mW+). This matters for your Omron output module's drive capability.
- Life expectancy: Often lower than the G2RL at full load (not an issue if you're switching infrequently).
My $890 mistake: The 8110 I ordered was for a bank of three 1.5kW servo drives. On paper, the total inrush current was under the 30A rating. But the 8110's coil drew 1.1W per relay. My Omron output module couldn't drive all three simultaneously. The relay partially engaged, the contacts arced, and I had to replace the entire output board. Lesson learned: Match the coil consumption to your driver, not just the contacts.
The verdict on this dimension:
- Use the G2RL when your load is under 10A, and your PLC output is a standard 0.5A or less. It's the safer, more efficient choice for 90% of signal-level comms gear.
- Use the Corp 8110 when you have a high-inrush load (transformers, motor starters, large contactors) and a PLC output (or separate interposing relay) that can handle the coil draw. Don't guess—verify your Omron output module's datasheet.
Dimension 2: Noise Immunity (The Killer for Data Comms)
This was the dimension that surprised me. I'd never considered relay 'noise' until it crashed a serial communication link.
Omron G2RL: Quieter than Expected
The G2RL uses a polarized magnetic circuit. This design inherently produces less electrical noise when the coil energizes and de-energizes. It also has a narrower 'bounce time'—meaning less chatter on the contacts.
Practical impact: In a cabinet with Omron PLCs, HMI screens, and serial (RS-232/485) or Ethernet/IP cabling, the G2RL is less likely to induce false signals. I've used them in panels where the relay wiring runs parallel to comms lines for 2-3 feet. No issues. According to Omron's application notes, keeping relay wiring at least 4 inches from data cables is still recommended—but the G2RL gives you more margin.
Corp 8110: The Noise Maker
Because the 8110 handles higher currents, it also generates a larger magnetic field when switching. Its bounce time is often longer, too.
Where it bit me: In September 2022, I had an 8110 switching a 12A heater element. The relay was about 8 inches from an Omron serial module's cable. Every time the contactor switched, it injected a spike that caused a comms timeout on the HMI. Took me two days to isolate the problem.
Solution: I swapped in a G2RL with a suitable snubber (RC circuit). The heater didn't care about the reduced rating (8A vs 12A? The heater was over-spec'd anyway). The comms issue vanished.
The verdict on this dimension:
- Use the G2RL near any data communication lines (EtherNet/IP, serial, discrete I/O compair). The lower noise profile is worth the trade-off in contact rating.
- Use the Corp 8110 in electrically 'quiet' parts of the panel, or when you can physically separate it from comms gear by 12+ inches. If that's impossible, budget for shielded cables and ferrite cores.
Dimension 3: Physical Fit & Wiring Effort
This sounds trivial until you're on your third cup of coffee and a relay won't fit under the duct cover.
Omron G2RL: Compact & PCB-Friendly
The G2RL is a standard 'low profile' relay package, often with a footprint of 29mm × 12.7mm. It fits Omron's industrial sockets (e.g., PYF-series) neatly.
- Socket option: Yes, standard 8-pin or 14-pin depending on variant.
- Wiring: Easy—socket terminals handle standard 16-14 AWG wire.
My preference: For new builds, I default to the G2RL and its socket. It's predictable, and every electrician I've worked with knows the layout. No surprises.
Corp 8110: Bigger, Tougher, More Annoying
The Corp 8110 is physically larger (about 35mm × 28mm) and often uses a different socket arrangement. Its terminals can handle thicker wire (12-10 AWG), which you'll need for the higher current.
- Socket option: Available, but less standardized across brands.
- Wiring: More effort—you're pulling heavier gauge wire, and the terminals are sometimes less accessible in a crowded panel.
Where it matters: If you're retrofitting an existing Omron panel that was laid out for G2RL-size relays, the 8110 might not fit in the same footprint. Check the physical dimensions before ordering. I've had to drill new mounting holes—once. Now I keep a physical sample in my desk for reference.
The verdict on this dimension:
- Use the G2RL for dense cabinets, new builds with Omron sockets, or any application where space is at a premium.
- Use the Corp 8110 only if you need the high current rating and have the physical space. Don't force it.
My Final Take: Which One to Buy?
I can't give you a one-size-fits-all answer. That would be dishonest. But I can tell you what I do.
Scenario 1: You're building a standard Omron PLC cabinet for general industrial control. Reach for the Omron G2RL. It covers almost everything—signal switching, small motors, valve control—and it plays nicely with your comms without extra hassle. I use it for 4 out of 5 jobs now.
Scenario 2: You need to switch a high-inrush load (like a motor starter or big transformer) and you have a dedicated interposing relay or a high-drive output module. The Corp 8110 is the right tool. Just keep it away from your data cables, and verify the coil current against your driver. That's the step I skipped.
Scenario 3: You're not sure. Go with the G2RL first. It's cheaper, quieter, and easier to work with. If it fails under load (which is unlikely if you've selected the right variant), then move up to the 8110. Better to learn on a $5 relay than a $200 repair.
Bottom line: Specialization wins. The vendor who tries to sell you a 'one relay fits all' solution probably hasn't burned an $890 hole in their budget. I have. Stick with the G2RL for your general Omron comms and control tasks, and save the 8110 for the specific jobs it was built for.
Prices are as of late-2024/early-2025; always verify current specs at omron.com and your vendor's site. I keep a separate coil budget for high-power relays now. Learn from my mistake.
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