GoodWe GMK330 - three-phase energy meter 230/400 V.

GoodWe GMK330 is a three-phase energy meter for 230/400 V networks, working within systems built around GoodWe hybrid and grid-tied inverters. The device occupies four DIN rail modules (72 mm wide), weighs 240 grams, has a polycarbonate housing and an operating range from −25 to +60 °C.

Why a three-phase system needs three-phase metering

It might seem you could fit a single-phase meter on one phase and multiply the result by three. In practice that does not work, and the reason is phase imbalance.

In a real house or business the load is almost never distributed evenly between phases. The kitchen runs on one, the pump and boiler room on another, lighting and sockets on the third. The difference can reach several kilowatts. A meter that sees only one phase will give the inverter a distorted picture, and the system will operate on false data.

What this changes for the inverter

Receiving data separately for each phase allows the inverter to perform two tasks correctly. The first is keeping generation within the site's actual consumption, avoiding export of surplus to the grid where that is unprofitable or prohibited by the connection terms.

The second is managing battery charging properly. Without three-phase metering the system may conclude that surplus exists when in reality two phases are overloaded and the spare capacity sits only on the third. Accurate per-phase data removes that error.

Four modules in the board: plan ahead

A width of 72 mm equals four standard DIN rail modules. In a private house's three-phase board, assembled before solar arrived, that much free space is far from always available.

Before ordering, therefore, open the board and count the free positions. If there are fewer than four, the design must allow from the outset for either extending the board or adding a separate enclosure for metering equipment. Discovering this during installation means stopping work and waiting for materials.

Operating conditions

An IP20 rating implies installation inside a distribution board. An operating temperature from −25 to +60 °C allows the board to sit in an unheated room or in an outdoor enclosure sheltered from direct precipitation.

The polycarbonate housing resists heat and mechanical stress — the standard material for modular equipment, which copes well with prolonged operation beside breakers that warm up under load.

What to ask before ordering

Meters in this series differ in how the measuring circuit is connected: direct wiring or operation through current transformers. For three-phase supplies with a high rating the second option is more common, and the transformers are selected for the specific supply current.

Clarify three things: your supply rating in amperes, the connection method of this particular model, and whether current transformers are included in the delivery. These questions look trivial right up until the equipment arrives on site.

Send us the inverter model and your supply diagram — we will verify compatibility against the documentation, calculate how much board space is required, and tell you whether additional components are needed.