Installing the inverter Growatt WIT 4-15K-HU - Anchors, AC Breakers, PV and Battery Cables

Installing the inverter Growatt It looks like two short chapters in the manual—and then you're drilling into the wall from memory anyway. This article organizes chapters 5 and 6 of the manual. WIT 4-15K-HU (rev. 2025-11, pp. 17-39 of the print; editorial translation from the English edition) in the order of actual work: location, support, suspension, grounding, AC side, PV side, and battery. All numbers—diameters, depths, moments, cross-sections, and circuit breaker currents—are taken from the tables and drawings in the manual, with the page address next to each. We discussed the requirements for the location itself (600/1000 mm spacing, no direct sunlight, tilt up to 15°) in more detail in the article on maintenance—we'll briefly recap them here, as everything else depends on them.

Before You Drill Your First Hole - Handling and Location

The inverter must be removed from the box by two people – the instructions explicitly require this, with a note about maintaining balance. The packaging includes front and bottom markings, and one CAUTION warning is worth mentioning, as breaking it will result in damage even before installation: do not place the device with the connection terminals on the ground, as the terminals are not designed to support the inverter's weight. Installation location: load-bearing wall that meets load-bearing requirements, non-flammable flooring, vertical operation or with a maximum rearward tilt of 15°, service clearances of 0,6 m around and 1 m at the front; do not place the device in an enclosed, tight space.

Installing the inverter Growatt on the support - anchors and moments

The sequence in Fig. 5.9 has four steps: tracing the mounting plate as if using a template, drilling, inserting expansion anchors, and screwing the bracket in place. The numbers you need on the drill are: a hole with a diameter of φ12 mm and a depth of 70 mm, and an anchor tightening torque of 396 kgf·cm (approximately 39 N·m—editor's calculation). Wall for anchors: solid concrete or brick, at least 100 mm thick. Suspension itself: the device is lifted with both hands, suspended on the bracket, and tightened with the securing screws to a torque of 50 kgf·cm, after which it is checked for proper seating and all screws are tightened. The dimensions of the mounting plate (including 475 × 298 mm in the main axes) are given in the instructions in Fig. 5.8—when prefabricating the brackets or mounting them on a supporting structure instead of a wall, it is worth transferring them to the design before the device arrives at the construction site. And a piece of advice that comes straight from the numbers: since the anchors require solid concrete or solid brick, plan the walls made of hollow bricks or sandwich panels with a through-mount fastening or frame from the very beginning - inverter installation Growatt on pins in a hollow brick is the shortest way to break the bracket with the 40-kilogram device.

Installation parameter	Value from the manual
Anchor hole	φ12 mm, depth 70 mm
Bracket anchor moment	396 kgf cm
Torque of the inverter mounting screws	50 kgf cm
Wall	solid concrete or brick, thickness ≥100 mm
Transfer	2 people, front/bottom markings on the box
Working position	vertical or backward tilt ≤15°

Grounding - First Cable, Not Last

Electrically mounting the inverter Growatt It starts with PE. The order from chapter 6.1 is mandatory: the grounding cable is connected to the inverter before any other cable—to protect people and equipment. All non-conducting metal parts of the system are grounded: frames, combiner box enclosures, switchboards, inverter, and batteries. For multiple inverters running in parallel, the manual requires equipotential bonding—enclosures, module frames, and batteries connected to the same grounding area. Two practical tips straight from the document: route the lightning protection ground as far from the protective ground as possible, and protect the ends of the grounding cables from rain. The torque on the PE terminal is 50 kgf·cm. This is the same torque as the mounting screws—in practice, one wrench with a single setting operates both the bracket and the grounding, simplifying work on a ladder.

AC Page - Breakers, Sections and Trap with Warranty

Before work: ensure the grid voltage and frequency are within acceptable limits, and that the DC disconnect switches and AC circuit breakers for the grid, generator, and battery are open. An AC circuit breaker on the grid side is mandatory: it ensures safe disconnection of the inverter from the main power supply in the event of a fault. The manual provides a complete set of recommended values ​​for four circuits:

Editorial note on missing value: in the AC cable table of the manual (p. 33 of the print) cell for WIT 4/5/6K-HU only contains the unit "mm²" without a number—this is a manufacturer's document composition error, not an oversight on our part. We don't guess at this value: select the cross-section based on calculations for the 32 A protection current, in accordance with industry standards and regulations, and confirm the catalog value with the technical department. The connection technique itself is precisely described: 11-13 mm insulation, crimp-sleeve terminals (a cold-pressed set is included, selection based on cross-section). And a warning you should be aware of before acceptance: damage resulting from failure to seal the output terminal gaps according to the instructions is outside the warranty scope—the full list of exclusions is provided in the article about warranty. WITNote that the four AC circuits are four separate devices in the switchboard—bypass and load have identical currents but different functions, and during commissioning, labeling them clearly on the schematic (grid/load/bypass/GEN, as on the inverter terminal labels) saves each subsequent crew guesswork.

PV Side - Three Limits That Inverter Installation Growatt cannot exceed

The section opens with a DANGER warning: modules in sunlight generate voltage, and string voltages connected in series can be lethal. Before connecting DC cables, cover the modules and ensure that DC disconnects are open. The three design limits from the manual are: string open-circuit voltage of a maximum of 1000 V DC, short-circuit current of each string not exceeding 50 A, and total panel power not exceeding twice the inverter input power. In addition, sound design principles include: modules in a string of the same model and recommended equal occupancy of both DC inputs, the sum of string currents within the maximum input current, and the current of a single path. MPPT up to 40 A

Implementation: PV cables with a cross-section of 4-6 mm², 8-10 mm insulation, crimping and pull-out testing – the connector should not be pulled out of the terminal. Use male and female connectors in pairs, with polarity checked before connecting the string. In parallel systems, the module frames enter a common equipotential bond, and the PV side is grounded before the PV cables. The power limit of twice the rated power is sometimes confused with a recommendation – it's a strict requirement: the instructions explicitly warn that breaking it can cause fire or damage to the inverter and exclude the manufacturer's liability. Therefore, plan PV generator oversizing consciously, with a plan in mind, not "by eye."

Battery side - OT, M8 and up to 10 meters

WIT The 4-15K-HU operates with a low-voltage battery with a recommended voltage of 51,2 V, so the currents are high and the connection rigor is the highest throughout the entire installation: the manual warns that a loose connection may cause overheating and damage to the device. Cable cross-sections from Table 6.3: 50 mm² for WIT 4/5/6K-HU and 50 or 120 mm² for WIT 8/10/12/15K-HU. Procedure from Fig. 6.14: stripping the insulation for the OT terminal (terminal included in the delivery accessories), crimping with a press, heat shrinking the connection and screwing to the input terminal with M8 screws - the drawing gives a torque of 198 kgf·cm (value from the graphic layer of Fig. 6.14). Two closing rules: grounding cable before the battery cable and the recommended battery cable length of no more than 10 m. Correct inverter installation Growatt on the DC side it ends right here - you can calculate the selection of the battery itself to the power of the inverter in the article about the battery for WIT 4-15K-HU; communication (8 RJ45 ports for BMS, counter, DRMS ​​and ShineMaster) we describe in articles about monitoring.

System Diagrams and Communication – What Else is in Chapter 6?

Chapter 6 opens with wiring diagrams for complete systems: a single inverter with a generator on the GEN port, an AC Couple variant with a grid inverter, Smart Load mode, and three units in parallel operation - before you start pulling cables, find the diagram that suits your architecture, because the R/S/T/N arrangement on the GRID, LOAD, and GEN terminals is described there. The communication layer is handled by eight RJ45 ports in the COM1/COM2 zones: communication with BMS battery, energy meter, DRMS, ShineBus/ShineMaster and EMS/VPP - pin descriptions can be found in Table 6.5 of the manual. The configuration of the monitoring itself (datalogger, application) is provided in the article about ShineWiFi-X i ShineWiLan-X2.

Installing the inverter Growatt The parallel variant adds two things beyond a single unit: common equipotential bonding of all enclosures and racks, and unique unit communication addresses. The latter are set during commissioning, according to the procedure in the article on operating modes. We discuss the physical spacing between adjacent inverters on a single wall (minimum 600 mm) in the article on maintenance. With three units, this makes the wall really wide, which is important to know at the proposal stage, not the installation stage.

What NOT to do during assembly

Installing the inverter Growatt usually breaks down in the same four places - all prohibitions come straight from chapters 5-6:

• Do not place the inverter on the terminals. The terminals do not carry the weight of the device - a moment of "leaning against the wall" during a break in installation can cost the replacement of the connections.
• Do not connect anything before grounding. The PE cable goes first - before the AC, PV and battery; on the PV side the manual repeats this separately.
• Do not work on thongs without covering the modules. String tension in the sun can be fatal - a tarp is a health and safety item, not a whim.
• Do not leave terminal penetrations unsealed. Damage resulting from this is expressly excluded from the warranty.

From the installer's practice

• Installing the inverter Growatt start by drawing the four AC circuits (grid/load/bypass/GEN) on the switchboard diagram - the circuit breaker table from the manual then translates into a shopping list in five minutes.
• Set the torques of 396/198/50 kgf·cm on a torque wrench before climbing the ladder and take a photo of the setting - a photo in the acceptance documentation puts an end to discussions during inspections.
• Run the battery cable along the actual route, not in a straight line - the 10 m limit for batteries in another room ends with redesigning if you check it only on site.
• Battery packs for WIT 4-15K from our offer include cables and a base - one catalog number completes the topic of cross-sections and OT terminals on the battery side (commercial recommendation).

Frequently asked questions about inverter installation Growatt (FAQ)

What anchors and walls are required for installing the inverter? Growatt WIT 4-15K-HU?

Expansion anchors in φ12 mm holes, 70 mm deep, tightened to 396 kgf cm torque; solid concrete or brick wall at least 100 mm thick. The mounting plate serves as a marking template.

What circuit breaker before the inverter?

On the mains side: 32 A (400 V) for WIT 4/5/6K-HU and 63 A for WIT 8/10/12/15K-HU; load and bypass circuits 25/50 A, GEN — 32/63 A, respectively. In Smart Load mode, the GEN circuit breaker is selected according to the power of smart loads.

What size AC cable for WIT 4/5/6K-HU?

The manual doesn't specify this—the cell for these models in the AC cable table is empty (document layout error; 10 mm² is specified for 8-15K). Calculate the cross-section for 32 A protection, in accordance with regulations, and confirm with the technical department. PVGroup.pl.

Can the battery cable be 15 meters long?

The manual recommends a length of no more than 10 m. For longer distances, plan a different battery location - this is the manufacturer's recommendation for a 51,2 V low-voltage system, where every meter of cable matters when it comes to operating currents.

Is it possible to install an inverter Growatt WIT can I do it alone?

The manual describes removing it from the packaging and carrying it as a two-person job, and hanging it on the bracket requires lifting it with both hands and maintaining balance.ace Electrical work in Chapter 6 is reserved for qualified electricians. In short: plan to transport and hang the equipment with two people; the rest can be completed by one qualified person.

Step-by-step assembly checklist

1. Location: load-bearing wall ≥100 mm, spacing 600/1000 mm, no sun, slope ≤15°.
2. Bracket: board marking, holes φ12×70 mm, anchors 396 kgf·cm.
3. Two-piece suspension, 50 kgf·cm screws, seat control.
4. Grounding of all system components - first cable, 50 kgf cm.
5. AC: circuit breakers according to the table, strip 11-13 mm, crimp terminals, bushing seal.
6. PV: modules shaded, polarity checked, limits 1000 V / 50 A / 2× power.
7. Battery: OT + M8 (198 kgf cm), heat shrink tubing, cable ≤10 m.
8. Before take-off: inverter installation Growatt ends the start-up procedure from the article on operating modes WIT — communication address, time and mode selection.

Complete set of documents: user manual WIT 4-15K-HU, quick guide i catalog card in our database, originals in download center Growatt. Equipment: Growatt WIT 8KW-HU i battery pack 5 kWh with cables and base, other powers in the category 3-phase hybrid inverters; selection of a set of counts configurator.

Sources

1. Growatt WIT 4-15K - User Manual (HU) — instructions WIT 4-15K-HU (rev. 2025-11), chapter 5-6, PDF pp. 21-43 (print 17-39)
2. Growatt WIT 4-15K - Quick Reference Guide (HU) — quick guide WIT 4-15K-HU
3. Growatt WIT 4-15K - Catalog Card — catalog card WIT 4-15K