QIT6L
Single-phase AC electrical panel 6 kWp for photovoltaic systems — SECSUN QIT6L. Includes residual current circuit breaker 1P+N 300mA class A — 6kA and surge arrester class II 20kA. Protection rating IP65 class II. Dimensions 164x200x116 mm. Light version without CEI 0-21 interface relay: pure AC protection for 1 single-phase inverter.
The QIT6L is the single-phase AC electrical panel for photovoltaic systems up to 6 kWp from the SECSUN line, made in Italy by Contact Italia. Composed of a residual current circuit breaker and a surge protector mounted on IP65 class II enclosure, it guarantees complete protection of the AC side of a single-phase inverter against overcurrents, earth leakage, and lightning surges.
What is the QIT6L AC panel for?
In a photovoltaic system, the AC panel is responsible for protecting the inverter from electrical events that may come from the grid (overvoltages, short circuits, earth fault currents). The QIT6L is intended for single-phase systems up to 6 kWp with a single inverter: it integrates a residual current circuit breaker with a 300 mA class A tripping threshold — ideal for inverters with EMI filters that generate high-frequency leakage currents — and a class II surge protector with a nominal current of 20 kA for protection against indirect lightning. The Light version does not include the CEI 0-21 interface relay: for systems requiring the interface panel approved according to CEI 0-21, see the QIT line with integrated interface.
QIT6L Technical Specifications
| Code | QIT6L |
| Nominal power | 6 kWp |
| System type | Single-phase, 1 inverter |
| Residual current circuit breaker | 1P+N — 20A/25A/32A — 6kA — 300mA class A |
| Surge protector | Class II, Imax 20kA single-phase |
| Degree of protection | IP65 class II |
| Panel dimensions | 164 x 200 x 116 mm (WxHxD) |
| Type | AC panel without CEI 0-21 interface |
| Manufacturer | SECSUN / Contact Italia — made in Italy |
| Supply | Pre-wired panel, ready to use |
When is the QIT6L used?
The QIT6L is suitable for single-phase photovoltaic systems up to 6 kW that already have a separate interface panel or where the local distributor does not require the interface relay (island systems, plug-and-play systems, replacement systems). It is particularly suitable for installers who want a compact, economical solution that complies with electrical protection standards (CEI EN 61439), to be paired with single-phase inverters such as Solax, Huawei SUN2000, Solis, Fronius, or similar.
Difference between AC panel and interface panel
The AC panel (like the QIT6L) protects the electrical circuit between inverter and grid with protections against overcurrents and earth leakage. The interface panel also includes the interface relay required by CEI 0-21 for the automatic disconnection of the inverter in case of frequency or voltage anomalies, as required by the grid operator. For systems connected to the public grid in Italy, the CEI 0-21 interface panel is mandatory according to the connection standard. For systems that already have the interface function integrated in the inverter (e.g. certain SUN2000 models with certified interface), the QIT6L as an AC protection panel may be sufficient: always check with your local grid distributor.
What is included in the supply
- Pre-wired QIT6L AC panel
- 1P+N residual current circuit breaker (selectable rating: 20A/25A/32A)
- Single-phase class II surge protector 20kA
- IP65 class II insulating enclosure
Frequently Asked Questions
Does the QIT6L include the CEI 0-21 interface relay?
No. The QIT6L is the Light version, that is, the AC protection panel only, without the CEI 0-21 interface relay. For photovoltaic systems connected to the Italian public grid that require the approved interface panel, it is necessary to purchase the version with integrated interface (QIT line with interface) or check if the inverter has an internal interface function certified by the local distributor.
Why is the QIT6L residual current device class A and not AC?
Modern photovoltaic inverters with EMI filters generate leakage currents with a residual DC component (unidirectional pulsed currents). A standard class AC RCD does not detect these currents and may not trip. The class A RCD in the QIT6L, on the other hand, can detect both sinusoidal alternating currents and pulsed currents with a DC component, ensuring adequate protection for modern photovoltaic inverters as required by CEI 64-8.
Which circuit breaker rating should I choose for the QIT6L?
The rating depends on the inverter's nominal current. For a single-phase 6 kW inverter at 230V, the nominal current is about 26A: typically, the 32A rating is used. For inverters with lower power (3-4 kW, current 13-17A), the 20A or 25A rating is sufficient. Always check the nominal AC output current shown on the inverter's datasheet and apply a 25% safety factor as required by the standard.
Is the QIT6L compatible with all single-phase inverters?
Yes, the QIT6L is compatible with any single-phase photovoltaic inverter up to 6 kW: Solax X1, Huawei SUN2000-3/4/5/6KTL, Solis Mini, Fronius Primo, Goodwe ES, ABB UNO, and others. The panel is independent of the inverter brand as it only performs AC circuit protection functions. The important thing is that the inverter's nominal current is compatible with the chosen circuit breaker rating.
Can the QIT6L be installed outdoors?
Yes. The IP65 protection rating of the QIT6L makes it suitable for outdoor installation, resisting dust and direct water jets. The class II enclosure also ensures protection against indirect contact without the need for grounding the casing. However, it is advisable to install it in a location sheltered from direct sunlight and rainwater accumulation to prolong the life of the internal components.
