A photovoltaic connector is selected in the wrong order more often than it is selected wrongly. Most mismatches happen because the connector is chosen from the module's datasheet first and the system's electrical conditions second. Work in this order instead: system voltage, then string current, then straight or branch, and only then the mating standard.
Step 1 — Let the system voltage set the connector class
The connector's rated voltage must be at least the array's maximum system voltage. This range is built in three classes, so the class follows the architecture rather than the other way round:
| Voltage class |
Model families |
| DC 1000 V |
PV-SL01, PV-SL01-1, PV-SL02, PV-SL02-1, PV-SL03, PV-SL03-1, PV-SLD01, PV-SLF01, PV-SLT2, PV-SLT3, PV-SLT4, PV-SLT5, PV-SLT6, PV-SLTX2, PV-SLTX3, PV-SLY3, PV-SLY4, PV-SLY5, Y-2/4, Y-2/6, Y-2/8 |
| DC 1500 V |
PV-SL04, PV-SL04-1, PV-SL05, PV-SL05-1, PV-SL05-2, PV-SL05-3, PV-SLF02 |
| DC 2000 V |
PV-SL06 |
Choosing a 1500 V connector for a 1000 V array is not automatically safer: the higher class usually costs more and may change the enclosure or clearance requirements of the surrounding equipment. Choose the class the system is designed to.
Step 2 — Check current against the string, not the module
Rated current is stated on the PV-SL01 and PV-SL02 family as 30 A at DC 1000 V. Compare that against the maximum current the string can deliver — which is the module's short-circuit current multiplied by the number of parallel modules on that string, corrected for the site's expected irradiance and temperature. A connector rated exactly at the module's nameplate current has no headroom.
Step 3 — Decide between a straight connector and a Y-type branch connector
Use a straight connector everywhere the wiring is one cable to one cable. Use a Y-type branch connector where the array wiring branches instead of running one-to-one: the Y-2/4, Y-2/6 and Y-2/8 models are supplied as 2-in-4-out, 2-in-6-out and 2-in-8-out at DC 1000 V. Confirm the input and output counts against the string layout you are wiring, and check the current at the shared point against the connector's rating — that is the point where the current concentrates.
Step 4 — Confirm the mating standard
The range is MC4-compatible. If the installation must mate with connectors already on site, state the exact connector or module series you are mating with and confirm the match before ordering — compatibility claims should be confirmed against the physical interface you already have, not assumed from the category name.
What to verify before you order
- The array's maximum system voltage and the resulting connector class.
- The maximum string current and the headroom above it.
- How many strings are branched at each point, and the total current there.
- The exact mating connector already installed, if any.
- The certification and derating rules of the market the system is being installed in.
- The conductor cross-section and insulation diameter the connector must accept.
Common selection mistakes
- Choosing by module nameplate current. The string can deliver more than one module's rating, and connectors are sized against the string.
- Over-specifying the voltage class. A higher class is not free, and it can force changes to surrounding equipment.
- Ignoring the current at the shared point. Where conductors converge, the current adds, and that figure is what the connector has to be rated for.
- Assuming compatibility instead of confirming it. Two connectors can both be called MC4-compatible and still differ at the interface.
- Ignoring the local standard. Derating and certification requirements change by market, and they change the acceptable model.
