| 1 | General-purpose electromechanical relays | Control panels, appliances, building systems, and industrial equipment. | IEC 61810-1 for basic safety and functional requirements of elementary relays. | Contact resistance, coil operation, dielectric withstand, temperature rise, and endurance. | Smaller packages, lower coil power, and improved automated production inspection. |
| 2 | PCB signal and power relays | Control boards, measurement equipment, telecom equipment, and power switching on printed circuit boards. | IEC 61810-1; IEC 60664-1 may be relevant to insulation coordination in equipment design. | Switching capacity, insulation spacing, solderability, coil-to-contact isolation, and operating life. | Higher-density layouts and designs tailored to specific board-level loads. |
| 3 | Automotive relays | Vehicle body electronics, lighting, HVAC, pumps, and auxiliary power circuits. | ISO 16750 series addresses environmental conditions and testing for electrical and electronic equipment in road vehicles; application requirements vary. | Vibration, temperature cycling, electrical endurance, terminal integrity, and resistance to vehicle electrical transients. | Higher-temperature capability and demand linked to vehicle electrification. |
| 4 | High-current and power relays | Battery systems, industrial power distribution, charging equipment, and high-load switching. | IEC 61810-1 where applicable; IEC 60947 series may apply to low-voltage switchgear and controlgear devices within its scope. | Contact temperature rise, arc behavior, current-carrying capability, terminal strength, and endurance under specified loads. | Greater attention to thermal management and switching performance in electrified systems. |
| 5 | Latching relays | Smart meters, energy-control systems, and equipment requiring state retention with reduced continuous coil power. | IEC 61810-1 for applicable elementary relay requirements; product-specific metering requirements may also apply. | Set/reset operation, mechanical retention, contact resistance, switching endurance, and pulse-coil performance. | Use in energy-aware control and remotely managed metering applications. |
| 6 | Solid-state relays (SSRs) | Heater control, process automation, lighting, and applications needing frequent switching without mechanical contacts. | IEC 62314 covers solid-state relays; other equipment-level standards may also apply. | On-state voltage or resistance, leakage current, isolation, thermal performance, and switching behavior. | Improved thermal design and integration with electronic control systems. |
| 7 | Reed relays | Test and measurement instruments, switching matrices, and low-level signal circuits. | IEC 61810-1 may apply to the relay; instrument-level requirements depend on the end equipment. | Contact resistance, insulation resistance, switching stability, coil operation, and mechanical endurance. | Continued demand for compact switching with low signal disturbance in instrumentation. |
| 8 | Safety relays and forcibly guided contact relays | Safety-related machine control, emergency-stop circuits, and monitoring circuits when used in a suitably designed system. | IEC 61810-3 specifies requirements for electromechanical elementary relays with forcibly guided (mechanically linked) contacts; machine-level safety standards also matter. | Contact linkage, fault detection behavior, dielectric strength, endurance, and documented production traceability. | More emphasis on verifiable safety functions and system-level documentation. |
| 9 | Thermal overload relays | Motor protection in industrial control panels, commonly alongside contactors and motor starters. | IEC 60947-4-1 addresses contactors and motor-starters, including relevant overload protection devices within its scope. | Trip characteristics, phase-loss response where specified, reset operation, temperature compensation, and calibration consistency. | Integration with electronic motor management and connected control panels. |
| 10 | Protection and monitoring relays | Power-system protection, feeder monitoring, and detection of electrical conditions such as overcurrent or voltage deviation. | IEC 60255 series covers measuring relays and protection equipment; the relevant part depends on the device function. | Measurement accuracy, pickup and timing behavior, insulation, electromagnetic compatibility, and functional verification. | Digital communications, event records, and coordination with increasingly automated grids. |