Standard Solution: Temporary Construction Site Power Supply Cabinet

Published: 11.06.2026 · Author: engineering department of LK Energy Group

Standard solution for a temporary construction site power supply cabinet: 400 A incoming supply, a separate 250 A power circuit through a contactor with local and remote control, and six 16 A branch circuits. The package includes 2 PDF sheets: the schematic diagram of the main circuits and the control circuit diagram. The drawings were produced by LK Energy Group engineers for an actual production order (2022). The PDF is freely available below; the DWG model is available free of charge after a short registration.

How the temporary power supply cabinet is built

During construction, the site is powered under a temporary scheme — until the facility's permanent network is put into operation. The unit that handles this task is the incoming/distribution cabinet: an incoming circuit breaker, a power circuit for the main consumer, and branch circuits for the site's smaller consumers.

This solution has a 400 A incoming supply with the PEN conductor split into PE and N inside the cabinet, and a grounding busbar (galvanized steel strip, 40x4). The main 250 A power circuit is switched by a contactor: it can be switched off with a button on the cabinet or remotely — an "I-0-II" selector switch chooses local or remote control, and the external signal is brought in on terminals X1. The contactor status is shown by "Ready" and "Running" indicator lamps. Six 16 A branch circuits are assembled on a separate busbar and protected by miniature circuit breakers.

Technical parameters of the solution

• Incoming supply: VA88-series incoming circuit breaker, 400 A; fed by a PEN conductor, split into PE and N at the incoming point
• Main consumer power circuit: VA51-39 250 A + KTI-series contactor, 330 A (type per the diagram; 220 V coil, AC3 category), AD31 3x25 busbars
• Contactor control: "Start"/"Stop" buttons (LAY5-BA31/BA41), LAY5-BD33 "I-0-II" selector switch (local/remote), X1:1–X1:2 terminals for the external remote-control circuit
• Signaling: AD-22DS 230 V lamps — green "KM Ready," red "KM Running"; control circuit protection — VA47-29 1P 6 A
• Branch circuits: 6 × VA47-29 3P 16 A on a FORK 3P 63 A busbar
• Busbars: AD31 4x40; PE busbar — galvanized steel strip 40x4, PV3 25 mm² conductor
• Documentation: 2 sheets (A1 + A2), 2022, diagrams in Ukrainian — individual labels of the original in Russian; the ratings for a specific implementation are agreed upon ordering

Package contents and downloads

Preview

DWG package after registration

You get the DWG model of the temporary power supply cabinet (main circuits + control circuits in a single AutoCAD file) free of charge after registration. Registration takes your name, phone and e-mail.

Frequently asked questions

The diagrams are provided as a reference standard solution. Adaptation to the specific facility, verification of protective device selectivity, and compliance with applicable norms (PUE, DSTU, DBN — state building codes) are provided by the design engineer. LK Energy Group is not liable for use of the solution without adaptation to the conditions of a specific facility.