Identification of All System Components
This domain tests component identification: can you find every major part, read its nameplate, confirm listing and ratings, and match it to the approved plans? You are looking for modules, inverters, combiners, DC/AC disconnects, overcurrent devices, rapid shutdown equipment, conductors, connectors, racking, grounding and bonding, batteries, and monitoring.
What to verify
- Modules: manufacturer, model, serial numbers, Voc, Isc, power, temperature coefficients, and listed connectors.
- Inverter: continuous output, maximum DC input voltage, MPPT range, utility-interactive listing, and rapid shutdown compatibility.
- Racking: UL 2703 listing for bonding and mechanical integration; module clamps and torque.
- DC/AC overcurrent devices and disconnect ratings; conductor insulation, ampacity, and temperature rating.
- Batteries and charge controllers: UL 9540 listing, voltage, chemistry, ventilation, and clearances.
- Labels and markings that identify the equipment and its source.
Worked example
A string has 12 modules with nameplate Voc = 41.2 V and a Voc temperature coefficient of −0.29%/°C. At a record low of −10°C, the correction is 1 + (−0.0029 × (−10 − 25)) = 1.1015, so string Voc ≈ 12 × 41.2 × 1.1015 = 545 V. The inverter maximum DC input is 550 V, so the string is acceptable but close; if the design used 13 modules (about 590 V), it would fail. The inspector records the module model, count, coefficient, and inverter rating, not just a pass/fail opinion.
Traps
- Using STC Voc without cold-temperature correction.
- Mixing connector brands or models within a string.
- Accepting unlisted racking as a bonding path.
- Missing a rapid shutdown device or its label.
- Reading an inverter AC rating as its DC input limit.