Micro-Inverter & Solar AC Connectors: C20 vs C28 vs M25 vs Q28
Updated 2026-10-02 · Shenzhen Coptic Electronics Co., Ltd.
A micro-inverter system has two kinds of connection: DC from each PV module to the inverter, and AC from the inverters to the grid. Outdoors, both must stay sealed for decades. Here is how CPENT's waterproof connector families compare.
Comparison
| Series | Type | Rating | IP (mated) | Wire range | Best for |
|---|---|---|---|---|---|
| C20 | Pre-moulded, 2P+E | 12 A / 300 V | IP67 / IP68 | 0.75–1.5 mm² (18–14 AWG) | Micro-inverter output and trunk cables |
| C28 | Pre-moulded, 2P+E | 25 A / 300 V | IP65 | 0.75–2.5 mm² (18–12 AWG) | Higher-current AC links |
| M25 | Pre-moulded plug + panel socket | 25 A / 300 V | IP67 / IP68 | 0.75–2.5 mm² (18–12 AWG) | Inverter and battery enclosures |
| Q28 | Field-assembly, screw type | 25 A / 300 V | IP65 / IP68 | 0.75–2.5 mm² (18–12 AWG) | On-site extension and repair |
| M20T | T-branch junction | On request | Waterproof | On request | Branching a trunk cable |
| MC4-type | DC PV connector | On request | Waterproof | PV cable | Module-to-inverter DC links, Y-branches |
All AC series share a 4000 V AC withstand test, contact resistance of ≤ 0.5 mΩ, UL94 V-0 housings and a −40 °C to +85 °C operating range.
How to choose
- Current. Add up the output current of every inverter on the branch. Up to 12 A, a C20 is enough. Above that, use a 25 A series (C28, M25 or Q28).
- Where the connector sits. On a cable end, use C20, C28 or Q28. On an enclosure wall, use the M25 with its panel socket.
- Factory or field termination. Pre-moulded connectors (C20, C28, M25) are sealed at our factory and are the most consistent. Q28 lets an installer cut a cable to length on site.
- Ingress protection. For roof and ground installations exposed to standing water, choose an IP68-rated series.
- Servicing. The C20 locks with a latch that opens only with the dedicated release tool, so it cannot be pulled apart by accident.
Complete cords
For plug-in balcony systems, CPENT supplies finished AC output cords with a national mains plug at one end and a C20 or C28 at the other, in the cable type and length you specify.
Connector interfaces differ between inverter brands. Send us the mating connector drawing or a sample and we will confirm compatibility before quoting.