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Relay / Contactor Options Comparison
Load Requirement
- External load: Spa Electric LV25-12 swimming pool LED light system
- Switched load: 240 VAC, 25 W
- Steady-state current estimate: 25 W / 240 VAC = 0.104 A RMS
- Requirement: switch active and neutral using 2-pole mains-rated contacts; do not switch PE.
Shortlist
Table
| Option | Type | Coil | Contact Form / Rating | Approx. Low-Qty Price | Procurement Notes | Design Impact |
|---|---|---|---|---|---|---|
| Finder 22.32.0.012.4320 | DIN modular contactor | 12 VAC/DC | 2 NO, 25 A, 440 VAC class | ~A$115 inc GST each from RS AU | Good Australian low-volume procurement, recognizable industrial part | Requires 12 V coil drive, not current 5 V rail |
| Finder 22.32.0.012.4520 | DIN modular contactor | 12 VDC | 1 NO + 1 NC, 25 A | ~A$105 inc GST each from RS AU | Easy RS AU procurement, but contact arrangement is not ideal for 2-pole switching because one pole is NC | Not recommended for active+neutral simultaneous NO switching |
| Phoenix Contact 2961299 | DIN rail relay module | 12 VDC | DPDT, 10 A | ~A$14 inc GST each from RS AU | Very low cost and easy AU procurement; check exact approvals/load category | Requires 12 V coil drive; relay module/socket style |
| Jaycar / Electus SY4065 | Plug-in relay | 12 VDC | DPDT, 10 A at 240 VAC | ~A$8.05 each at qty 10 from Jaycar | Cheapest local source; good for prototypes, weaker compliance/professional procurement story | Requires relay cradle/socket and 12 V coil drive |
| Omron G6B-2214P-US DC12 | PCB power relay | 12 VDC | DPST-NO, 5 A, AC-rated | ~US$9.81 from DigiKey | Reputable relay, good stock; PCB-mounted mains requires careful compliance/layout | Requires 12 V coil drive and brings mains onto PCB |
| Panasonic DSP2A-L2-DC5V | PCB latching relay | 5 V dual coil | DPST-NO, 5 A, 250 VAC | ~US$8.77 from Mouser | Matches existing dual-coil 5 V architecture; reputable brand | Brings mains contacts onto PCB; less preferred than external contactor stage |
| Same Sky PRL1-5V-DC-2A | PCB latching relay | 5 V dual coil | DPST-NO, 16 A, 277 VAC listed | ~US$4.90 from Mouser | Cheapest 5 V latching option; good stock in search result | Needs deeper approval/datasheet review before product use; PCB mains separation required |
| Omron G7L-2A-T DC12 | Power relay | 12 VDC | DPST-NO, 25 A, 277 VAC | element14/DigiKey class, ~US$20+ or AU supplier-dependent | Very robust contact margin | Requires 12 V coil drive; larger relay, may be overkill |
Recommendation
For product-oriented low-volume batches of ~10 units, prefer an external DIN-rail/contact-module approach over PCB-mounted mains contacts.
User Decision
Selected relay module: Phoenix Contact 2961299 DIN rail relay module, 12 VDC coil, DPDT / 10 A class, sourced via RS Australia class distribution. This is the project relay baseline unless later superseded by compliance review.
Recommended baseline
Finder 22.32.0.012.4320 or equivalent 2-pole, 2-NO modular contactor with 12 VAC/DC coil.
Rationale:
- Strongest compliance/procurement story among the researched options.
- True 2-pole normally-open contactor behavior for active + neutral switching.
- Large contact margin relative to 0.104 A steady-state load.
- Available from RS Australia in low quantities.
Tradeoff:
- It is expensive at roughly A$115 each and requires a 12 V coil supply/driver, so the current 5 V relay-driver section should be revised if this is selected.
Selected cost-optimized pilot / low-volume option
Phoenix Contact 2961299 DIN rail relay module, if its approvals and exact contact load category are acceptable after datasheet review.
Rationale:
- Much cheaper at roughly A$14 each.
- Easy low-volume AU procurement.
- Contact rating appears far above the 25 W load.
Tradeoff:
- Needs exact datasheet/compliance review before product release.
- Still requires 12 V coil drive.
Not recommended as final product default
Jaycar/Electus plug-in relays are attractive for quick prototypes, but are weaker for a compliance-reviewed commercial spa/pool-adjacent product. PCB latching relays are cheap and can match the existing 5 V architecture, but they put mains contacts on or near the control PCB and increase layout/compliance burden.
Required Schematic Update if Recommended Contactor is Chosen
If the Finder/Phoenix 12 V coil path is selected:
- Replace the current +5V relay coil output assumption with a 12 V coil supply or external 12 V coil input.
- Update relay driver MOSFET voltage/current ratings and flyback clamp.
- Update connectors and labels to RELAY_COIL_12V_SET/RESET or CONTACTOR_COIL_12V.
- Re-run power budget for coil current and sealed-enclosure thermal rise.
Decision Status
Phoenix Contact 2961299 selected. Remaining decision: provide the 12 V relay coil power either from an external 12 V SELV input or by revising the controller PSU architecture to add a 12 V rail.
Load Requirement
Shortlist
Recommendation
User Decision
Recommended baseline
Selected cost-optimized pilot / low-volume option
Not recommended as final product default
Required Schematic Update if Recommended Contactor is Chosen
Decision Status
