The GHM distribution box and GGD switchgear serve different levels in a building's power distribution hierarchy. The GGD is a large, floor-standing main distribution switchgear rated up to 4000A, typically installed at the main incoming point of a building where it receives power from the transformer and distributes it to sub-main circuits. The GHM is a smaller, modular enclosure rated up to 630A, used downstream of the GGD as a sub-main distribution board, lighting board, or small motor control panel. The GHM uses DIN-rail mounted components (MCBs, contactors) for flexibility and quick replacement, while the GGD uses larger fixed-mounted MCCBs and busbar systems for high-current distribution. In a typical installation, the GGD feeds multiple GHM boxes on each floor or zone, with each GHM distributing power to final circuits. The GHM is also available in wall-mounted form, making it suitable for space-constrained locations where a floor-standing GGD cannot be installed.

The choice of IP rating depends on the installation environment: (1) IP30 — recommended for clean, dry indoor electrical rooms and switch rooms with controlled access, where protection against solid objects larger than 2.5mm is sufficient and no water ingress is expected. This is the most common and cost-effective rating for indoor building distribution. (2) IP40 — suitable for indoor environments with higher dust levels or where additional protection against solid objects larger than 1mm is required, such as industrial production areas or warehouses with airborne dust. (3) IP54 — recommended for semi-outdoor locations, covered outdoor areas, car parks, humid basements, or any environment where water splash or dust ingress is possible. IP54 provides dust-protected (limited ingress) and splash-proof protection from all directions. For fully outdoor installations with direct rain exposure, we recommend the JP series outdoor distribution box or installing the GHM inside a weatherproof kiosk. Always match the IP rating to the actual environmental conditions of the installation site.

Yes, the GHM series is specifically designed for custom assembly. When you provide your single-line diagram (SLD) or panel layout drawing, our engineering team will select the appropriate enclosure size, arrange the DIN rails and busbars, and populate the box with the exact components you specify — including MCBs, MCCBs, RCCBs, RCBOs, contactors, thermal relays, timers, control transformers, and terminal blocks. We can accommodate components from Schneider, Siemens, ABB, CHINT, Delixi, or any other brand you prefer. We will return a detailed panel layout drawing and BOM for your approval before manufacturing. Typical customization includes the number of outgoing circuits, current ratings, tripping characteristics (B, C, D curves), auxiliary contacts, indicator lights, and metering. Lead time for custom-assembled GHM boxes is typically 15–25 working days depending on component availability and order quantity.

The maximum number of outgoing circuits depends on the enclosure size and the current rating of each circuit. GHM enclosures are available in multiple standard sizes, each with a defined number of DIN-rail mounting positions (often expressed in "modules" or "units," where one module = 17.5mm width for a single-pole MCB). A typical mid-size GHM box can accommodate 12–24 single-pole MCBs, while larger floor-standing versions can hold 36–60+ circuits. For three-phase circuits, each circuit occupies 3 modules. The main busbar current rating (up to 630A) must also be considered — the sum of all outgoing circuit currents cannot exceed the main busbar rating after applying diversity factors per IEC 61439. For projects requiring more circuits than a single enclosure can provide, multiple GHM boxes can be installed in parallel, each fed from a common main busbar or from upstream sub-main distribution. Our engineers can calculate the optimal enclosure size and circuit count based on your load schedule.

Yes, the GHM box is well-suited for small to medium motor control applications. It can accommodate DIN-rail mounted contactors, thermal overload relays, control transformers, timers, and auxiliary relays to build direct-on-line (DOL) starters, star-delta starters, or forward-reverse motor control circuits. Each motor starter circuit typically consists of an MCB or MCCB for short-circuit protection, a contactor for switching, and a thermal overload relay for motor protection. For motor control applications, the enclosure must be sized to accommodate the additional components and provide adequate heat dissipation — contactors generate heat during operation, and multiple contactors in a confined space may require derating. For larger motors (above 55kW) or complex motor control centers (MCC), we recommend the GCS or MNS withdrawable switchgear instead. When specifying a GHM box for motor control, please provide the motor power ratings, starting method, and duty cycle so we can verify the thermal rating of the enclosure.

The choice between wall-mounted and floor-standing depends on the enclosure size, weight, and available installation space: (1) Wall-mounted — recommended for smaller enclosures (typically up to 600mm width and 800mm height) with total installed weight under 80kg. Wall-mounted boxes save floor space and are ideal for corridors, stairwells, and small electrical closets. Ensure the mounting wall can support the load; use appropriate wall anchors for concrete or masonry walls. (2) Floor-standing — required for larger enclosures (above 600×800mm) or when the total weight exceeds 80kg, especially for boxes rated above 250A on the main busbar. Floor-standing boxes are bolted to the floor and may require a concrete plinth or cable trench for bottom cable entry. For high-current applications (400A–630A), floor-standing is always recommended due to the larger busbar cross-section and cable bending space required. As a general rule, if the main busbar rating is 250A or below, wall-mounted is usually suitable; above 250A, floor-standing is recommended.