Views: 0 Author: ShangKun Publish Time: 2026-11-13 Origin: Site
In a distributed PV plant, the string combiner box and the inverter station are the two assemblies where DC cabling, surge protection and monitoring boards sit outside a controlled environment. They are bolted to tracker frames, flat rooftops, desert ground mounts and floating pontoons. Everything inside is rated for decades; the door is the part an operator touches with gloves on, in wind, at 45 °C or below zero.
We build enclosure hardware for these cabinets, and the failure patterns we see in the field are remarkably consistent. They are almost never about the lock body breaking. They are about the seal losing its load.
Between them, the fittings on a PV enclosure carry five jobs: hold the gasket under load, stay operable with a gloved hand after years of UV exposure, resist the local corrosion environment, keep the door at a safe angle during service, and control who opens it. Each job points to a different fitting, which is why a well-specified combiner box usually has three or four different models on it rather than one.
The selection below is drawn from our standard range and matches the door types common in PV cabinets. Every model is a production item, not a concept.
Strong closing flex with clear feedback, which is what a technician in gloves needs on a 1.5–2 m inverter door. The adjustable pawl absorbs the tolerance stack of a double-insulated door without shimming the latch body.
View SK1-071 The model we specify for coastal sites, floating PV and agri-PV, where a coated zinc body would eventually show a corrosion line at the pedestal. Left and right versions cover mirrored door layouts on the same cabinet.
View SK1-055 Short envelope, so it fits a string combiner where a swing handle would foul the cable tray or the mounting bracket. The spring structure keeps the seal loaded even when the door is slightly out of square after years of thermal cycling.
View SK3-31S-1 Holds the door at the angle the technician leaves it at, instead of snapping to fully open. Lift-off release lets the door be removed and set aside in a narrow inverter row, and the inside fixing keeps the painted outer face clean for a visible OEM brand.
View SK2-010 For the small accessory doors on the same cabinet: the monitoring and communication compartment, the SPD window, the fuse access panel. Small enough not to dominate a compact enclosure, and the lift-off action speeds up board replacement.
View SK2-009 Sits flush in the door so nothing protrudes into a walkway or a lifting path. The cylinder gives access control on recombiner and communication cabinets that carry live DC or telemetry, and the full stainless body suits wash-down and coastal atmospheres.
View SK1-844PV cabinets are usually built from four or five enclosure types. The table below is how we normally allocate hardware across a single plant.
| Enclosure | Door | Latch set | Hinge set |
|---|---|---|---|
| Central inverter station | 1.5–2 m single or double leaf, gasket seal | SK1-071 swing handle, one per leaf | SK2-010 torque hinge, 3 per leaf |
| String combiner box, 600 × 800 | Flat door, single leaf | SK3-31S-1 toggle latch × 2, or SK1-055 for coastal sites | SK2-009 pair |
| DC recombiner / distribution | Flush door, walkway side | SK1-844 embedded flat lock | SK2-010 × 2 |
| Monitoring and communication compartment | Small accessory door | SK1-844 keyed flat lock | SK2-009 pair |
| Skid-mounted MV station | Heavy double door | SK1-071 × 2 with keyed-alike cylinders | SK2-010, 3–4 per leaf |
The wider range behind these models — panel locks, draw latches, handles and hinges for power box doors and electrical equipment enclosures — is indexed by application, and the new energy industry page collects the fittings used across PV, storage and charging infrastructure.
This decision affects field life more than any other, and it is usually made once per project rather than per part.
| Property | SUS304 stainless | ZDC zinc alloy |
|---|---|---|
| Corrosion | Specified for coastal, floating and agri-PV with ammonia or fertiliser dust | Adequate inland once chrome plated or painted; watch the pedestal and screw threads |
| Surface damage | A scratch is less likely to start a corrosion cell | Coating damage exposes the alloy and corrosion spreads from the chip |
| Shape freedom | Machined forms, straighter geometry | Complex ergonomic handles and housings at lower cost |
| Finishes | Wiredrawing, polishing, vibration ground | Bright chrome, black paint, matt black, custom colour |
| Weight | Heavier at the same envelope | Lighter — matters on a door already carrying a bracket |
| Typical use in PV | Outdoor door latch, hinge pin, exposed screws | Internal panels, accessory doors, handle bodies |
Five lines in the hardware specification do most of the work. They are the ones we ask for when a cabinet builder sends a drawing, and they remove almost all of the back-and-forth before a sample is made.
Much of the hardware on a PV cabinet is not the catalogue version. Door thickness, pedestal height, handle angle, keying and the brand moulded into the housing all change with the enclosure design. KUNLONG designs and manufactures locks, latches, hinges and handles for enclosure builders, and the adjustable range is engineered for exactly this: standard bodies with configurable mounting, pawl travel, handing, cylinder and finish.
What we need to quote accurately: door drawing with thickness and opening direction, gasket specification and target IP rating, expected annual volume per model, and the corrosion environment. A selection and a sample plan come back within one working day.
Tell us the enclosure type, door thickness, gasket and target IP rating. You get a fitting list, a quotation and a sample plan — usually the next working day.
