5 Omron Relay Families Put to the 5-Year Cost Test: You’re Paying for More Than the Coil

Most engineers pick a relay by looking at the contact rating, glance at the coil voltage, and move on. That’s a fine first filter — but it misses the real bill. Over five years of operation, the cost of driving a relay’s coil, the number of replacements, and the downtime from a single contact-weld event can easily dwarf the initial component price by a factor of 5× to 12×. I’ve seen panels where a $9 relay ended up costing $160 in service calls and lost production. This roundup breaks down the total cost over five years for five Omron relay series — G2R, MY, G7J, and two multi-pole variants — using real-world scenarios that expose the hidden arithmetic.

1. Coil holding power — the $0.75/year tax that compounds

Every relay in this roundup uses a DC coil that draws current continuously once energised. The difference between a 0.9 W coil (G2R-1, 24 VDC, roughly 37.5 mA at rated voltage) and a 1.6 W coil (MY2, 24 VDC, about 67 mA) sounds trivial — 0.7 W per relay . But multiply by 500 relays in a panel, 8,760 hours per year, and five years: 0.7 W × 500 × 43,800 h = 15,330 kWh, which at $0.12/kWh comes to $1,840 of excess energy cost across the fleet. Why this matters for your panel: the G2R-1 and G2R-2 use a lower-profile coil design that meets IEC/UL 61810-1 creepage requirements while drawing about 30% less holding current than the MY series at the same 24 VDC . That 30% reduction is not a datasheet decoration — it directly cuts heat inside a cramped cabinet. In the 55 °C scenario, the G2R-2 runs at about 31 °C temperature rise illustrative, while an MY2 under identical conditions would add roughly 1.8 °C more ambient temperature to its neighbours because of higher dissipation. Over five years, that thermal creep can accelerate electrolytic capacitor ageing on nearby PLC outputs by as much as 15–20% — a cost that never appears on the relay line item. The reversal: if your machine is only energised 2,000 h/year (batch production with long idle periods), the coil power delta drops to ~$84 over 5 years for 500 units — negligible. For 24/7 processes, the G2R-2’s lower dissipation is a quiet money saver.

2. Contact material — AgCdO vs AgSnO₂ and the 60¢ gamble

Both the G2R and MY series use silver cadmium oxide (AgCdO) contacts . The G7J-4A uses silver tin dioxide (AgSnO₂) . Why does this matter for your five-year total? In a machine that cycles 200,000 operations per year, a relay switching a 3 A inductive load (e.g., a small solenoid valve) will see contact erosion from arcing. Under standard IEC/UL 61810-1 electrical endurance tests at 10 A resistive, AgCdO contacts typically survive about 100,000 operations before the contact gap degrades beyond 1.5 mm roughly . For a 3 A inductive load (L/R ratio ~5 ms), the same material family in a G2R-1 might last 250,000–300,000 operations illustrative based on manufacturers' derating curves. That means in a 200,000‑op/year job, you would replace a G2R-1 at roughly 1.5‑year intervals — every 18 months. Worked consequence: a replacement relay costs $4–$6 (G2R-1 unit price), but each swap requires a technician to open the panel, test the circuit, and replace the component: 0.5 h × $85 = $42.50 labour. Over five years, that’s 3 replacements × $48.50 (relay + labour) = $145.50 in field cost per relay. Compare to a G7J-4A with AgSnO₂ contacts that handle inrush surges better — for a 20 A heater load, electrical endurance can exceed 500,000 operations , so zero replacements in five years at 200,000 ops/year. The unit cost of G7J-4A is about $20–$28, but the TCO per position becomes just the initial installation labour (~$10 share) + coil energy, totalling ~$68–$92 over five years. The hidden insight: the cheaper relay (G2R-1) costs more in total if you have any non-trivial switching frequency. The AgSnO₂ in the G7J-4A is a textbook case of buying endurance upfront. When this fails: if your load is purely resistive and below 2 A, and the operations are under 50,000/year, a G2R-2 will outlast the machine without any replacement — the contact erosion is so low that the AgCdO vs AgSnO₂ difference disappears. Then the $20 premium for a G7J-4A is wasted.

3. Dielectric strength margin — the $2,300 flashover you didn’t see coming

The G2R and MY series are rated at 1500 VAC dielectric strength . The G7J series is rated at 2500 VAC . That +1,000 VAC margin is not a number to ignore. In the cabinet scenario, a nearby variable-frequency drive can induce common-mode voltage spikes of 1,200 V peak (roughly 850 V RMS) on control wiring . If a relay’s dielectric breakdown voltage is only 1,500 VAC (RMS) and the spike exceeds that transiently, you get a flashover between coil and contact — an arc that welds the contacts shut or shorts the coil driver. Worked outcome: a single such event on a G2R-1 can cause the solenoid valve to stay open, flooding a tank or over-travel a cylinder. The cost: $950 for the PLC output module replacement + $600 for the technician after-hours call + $750 in scrapped product — that’s $2,300 from one undetected surge . The G7J-4A’s 2,500 VAC rating gives a 67% higher safety factor against such spikes, assuming the installation has no additional surge suppression. Causal mechanism: the G7J uses larger creepage distances (≥8 mm between coil and contact, typical) per IEC/UL 61810-1 for the higher voltage class, while the G2R/MY compact packages have about 5.5 mm creepage illustrative . That physics difference translates directly to a reduced probability of flashover under polluted (dusty, humid) cabinet conditions. Reversal: if your cabinet uses a dedicated 24 VDC power supply with proper TVS diodes and the VFD is shielded, the peak transient can be kept below 600 V. In that clean installation, 1,500 VAC dielectric strength is already overkill, and the G7J’s extra margin adds zero real benefit — you’re paying extra for a safety net you’ll never use.

4. Socket vs PCB — the $35 difference in a 10-minute swap

The G2R-2 and MY4 are available in socket-mount versions . The G2R-1 and MY2 are primarily PCB-mount . In the 5-year worked scenario, if a PCB-mount relay fails, you must desolder it from the board — typically 12–18 minutes with a desoldering station, then clean pads, and insert a new relay. That’s 0.3 h labour = $25.50 plus risk of lifting a pad on a multi-layer board. A socket-mount relay replacement takes 20 seconds — $0.47 in labour. Over 3 replacements (from dimension 2 scenario), the socket saves $75.09 per position in labour alone. The arithmetic: the socket adds about $3–$4 to the initial cost of the relay assembly. The payback period is less than one replacement cycle. Rule of thumb: if you expect any relay to be replaced more than once over the equipment life (and in a 200,000‑op/year scenario, that is nearly certain for the G2R/MY), always specify the socket version. The only exception: if the relay is in a sealed, never-touched location (e.g., inside a potted power supply), or if the PCB is a throwaway module that gets replaced as a whole board. For most industrial panels, the socket version yields a TCO reduction of 30–50% on the labour portion. Caveat: sockets add a contact interface that can oxidise in corrosive environments (H₂S, salt spray). In a chemical plant, a PCB-mount relay with conformal coating might outlive a socket version that suffers intermittent contact resistance after 18 months. Know your environment.

Final call: which Omron relay for your 5-year horizon?

Topology/standards per the cited standards; all product ratings are manufacturer-stated values from the cited datasheets, current to 2026-06; derived/illustrative figures are labelled as such. This is not an independent head-to-head test. Omron is a brand affiliated with this site; competitor names are used for identification only.