Panel space is one of those problems that never really goes away. Every new project seems to want more I/O, more monitoring, and more protection devices crammed into the same enclosure — or a smaller one, if the customer's trying to save on cabinet costs.
Solid state relays have always been a solid option for switching heating elements, motors, and resistive loads without the wear and noise of a mechanical contactor. The catch has traditionally been size — the classic "hockey puck" SSR takes up a fair chunk of DIN rail or panel real estate, especially once you've added a heatsink.
That's starting to change. A newer generation of miniature SSRs is now hitting the market that can handle the same kind of loads. Celduc Relais’ SF48340 is rated at 30A at 230VAC in a package that is only 30% of the footprint of a standard hockey puck unit. which starts to matter when you're trying to fit a relay bank into a slimline enclosure or retrofit extra circuits into an existing panel without a re-build.
This information is for general purposes only, please contact us on 03 9720 4522 or sales@practicalcontrol.com.au to discuss your specific requirements.
Panel space is one of those problems that never really goes away. Every new project seems to want more I/O, more monitoring, and more protection devices crammed into the same enclosure — or a smaller one, if the customer's trying to save on cabinet costs.
Solid state relays have always been a solid option for switching heating elements, motors, and resistive loads without the wear and noise of a mechanical contactor. The catch has traditionally been size — the classic "hockey puck" SSR takes up a fair chunk of DIN rail or panel real estate, especially once you've added a heatsink.
That's starting to change. A newer generation of miniature SSRs is now hitting the market that can handle the same kind of loads. Celduc Relais’ SF548340 is rated at 30A at 230VAC in a package that is only 30% of the footprint of a standard hockey puck unit. which starts to matter when you're trying to fit a relay bank into a slimline enclosure or retrofit extra circuits into an existing panel without a re-build.
If you're considering a miniature SSR for a panel design or upgrade, a few things are worth checking before you commit:
Switching capacity vs. your actual load
A 30A rating sounds generous, but derating applies once you factor in ambient temperature, panel ventilation, and whether the unit is mounted on a heatsink. Don't take the headline figure as the number you can run continuously in a sealed enclosure.
Control voltage range
Most miniature SSRs now accept a wide DC control range (commonly 3–32VDC), which makes them compatible with PLC outputs across most common platforms — handy if you're standardising on one relay type across different control systems.
Terminal type
FASTON (quick-connect) terminals are increasingly common on the smaller units and make for faster wiring and easier replacement during maintenance — worth considering if the panel will see regular servicing.
Thermal management
Smaller body, same current — that heat has to go somewhere. Check whether the unit needs a dedicated heatsink at your expected load, and factor that into your panel layout from the start rather than as an afterthought.
Certifications for your market
If equipment is heading export, confirm CE/UKCA, UL, and VDE coverage as relevant, plus RoHS compliance for environmental requirements.
Miniature SSRs are showing up most often in:
- Heating and temperature control circuits, where multiple zones each need their own relay
- Packaging and processing machinery with tight enclosure budgets
- Motor and resistive load control on retrofits where there's no room to expand the panel
- Distributed control setups, where smaller relays near the load reduce wiring runs
If you're specifying a new panel — or trying to squeeze extra capacity into an existing one — it's worth checking whether a miniature SSR can do the job a standard hockey puck unit used to. The performance numbers are largely catching up, and the space savings can be the difference between a re-design and a straightforward retrofit.
If you're not sure which option suits your application, get in touch — we're happy to talk through current ratings, control compatibility, and thermal considerations for your specific panel.