KNOWLEDGE CENTER
BUILDING YOUR POWER GRID.
Understand how main, intermediate and final distribution work together to deliver power from the source to the equipment.
This guide provides an overview of how to structure your power grid, select the right distribution units and consider the protection required throughout the system. It introduces practices that support safety, efficiency and compliance with applicable requirements, including standards such as EN 61439-1 and EN 61439-4 where applicable.
SYSTEM ENGINEERING
THE RIGHT SOLUTION STARTS WITH THE WHOLE GRID.
Before designing an individual unit, we understand how power needs to move through the complete application.
We review the available power source, connected loads, distribution points, cable distances, environmental conditions and operational requirements. Based on this, we recommend the distribution architecture and protection levels required across the grid.
MAIN DISTRIBUTION
Receives power from the source and provides the primary distribution and protection for downstream circuits.
INTERMEDIATE DISTRIBUTION
Redistributes power closer to individual production areas, departments or technical systems.
FINAL DISTRIBUTION
Provides the final power connections close to individual devices or groups of equipment.
CABLE INFRASTRUCTURE
Connects every distribution level through the appropriate cable assemblies, connectors and adapters.
MDU, IDU and FDU describe a unit’s role within the power grid. The same unit can serve different roles in different layouts, and some applications need fewer distribution stages. The ratings below are typical examples; the final selection follows the application.
01 · MAIN DISTRIBUTION
MAIN DISTRIBUTION UNIT (MDU)
The MDU receives power from the site supply or generator and distributes it to the main areas of the production. It is the starting point for organising outgoing supplies, protection and monitoring across the grid.
- CAPACITY AND CONNECTIONS
- Typical MDU applications use ratings from 125A to 400A. We select the incoming supply and outgoing circuits around the expected demand, available power and distribution layout.
- OVERCURRENT PROTECTION
- MCBs or MCCBs protect circuits against overloads and short circuits. Their ratings, breaking capacities and operating characteristics must suit the supply, cables and downstream equipment.
- COORDINATED PROTECTION
- We consider upstream and downstream protection together. The aim is for a fault to disconnect the affected circuit while allowing unaffected areas to continue operating. Selectivity must be verified for the selected devices and operating conditions.
- VOLTAGE MONITORING
- Voltage monitoring relays can detect supply abnormalities such as phase loss, overvoltage or undervoltage. Where automatic disconnection is required, the relay is integrated with an appropriate switching or tripping device.
- VISIBILITY AND CONTROL
- Metering, status indication and emergency switching can be specified to suit the application. These features help operators understand the supply conditions and manage the main distribution point.
ExampleAt a large event, an MDU can supply separate distribution areas for the stage, video systems and production facilities.
02 · INTERMEDIATE DISTRIBUTION
INTERMEDIATE DISTRIBUTION UNIT (IDU)
The IDU brings power distribution closer to a stage, department or production zone. It takes an upstream supply and divides it into circuits serving local equipment or final distribution units.
- LOCAL CAPACITY
- Typical IDU applications use ratings from 32A to 125A. The appropriate rating depends on the expected demand within the area and the available upstream supply.
- OUTGOING CIRCUITS
- The number, type and rating of the outlets follow the local distribution plan. Grouping connections around the working area makes deployment and fault identification more straightforward.
- PROTECTION AND MONITORING
- Protection is coordinated with the incoming supply, outgoing cables and downstream circuits. Voltage monitoring, metering and emergency switching can be included where the application requires them.
- LOOP-THROUGH CONNECTIONS
- Where fitted, a loop-through connection can supply another compatible unit. The connected units share the available upstream capacity, so their combined demand must be considered.
ExampleA 63A IDU can serve a production zone, supplying several final distribution points near the equipment.
03 · FINAL DISTRIBUTION
FINAL DISTRIBUTION UNIT (FDU)
The FDU provides power connections close to the equipment. It serves individual devices or small groups of loads, placing the required outlets where the production team needs them.
- EQUIPMENT CONNECTIONS
- Outlet types and quantities follow the connected equipment. Configurations may include Schuko, powerCON or CEE connections, with ratings and connector types selected for the application.
- TYPICAL SUPPLIES
- Typical FDU applications use 16A or 32A supplies. Selection depends on the combined demand of the connected equipment and the capacity of the upstream circuit.
- CIRCUIT PROTECTION
- Final circuits require protection appropriate to the connected loads, cables and installation. We consider this together with the upstream protection and the selected product configuration.
- PLACEMENT AND HANDLING
- A practical FDU fits the working area, keeps connectors accessible and supports straightforward deployment. Its enclosure and connections must suit the operating environment.
- OPERATIONAL FEATURES
- Working lights and status indicators, where fitted, can make connections easier to identify and support troubleshooting during setup and operation.
ExampleAn FDU can supply cameras, audio equipment, lighting fixtures or production workstations close to their operating position.
APPLICATION REQUIREMENTS
SELECT FOR THE COMPLETE APPLICATION.
Current rating is one part of the decision. The supply, connected loads and operating environment determine how the complete system should be configured.
SUPPLY AND EARTHING
Confirm the supply characteristics, earthing arrangement and available fault current before selecting protection. Generator and utility supplies can require different protection assessments.
LOADS AND PHASE BALANCE
Consider the expected demand on each phase, equipment start-up currents and the behaviour of electronic loads. Harmonic currents can increase neutral loading and must be considered when sizing the system.
ENCLOSURE AND ENVIRONMENT
Select the enclosure, connectors and cable protection for the actual exposure to water, dust, impact and handling. Use the product’s documented IP rating and operating conditions when assessing suitability.
CABLE INFRASTRUCTURE
CONNECTING EVERY LEVEL OF THE GRID.
Cable assemblies connect the source, distribution units and final equipment. Their selection forms part of the protection and distribution design.
We consider cable length, conductor size, current-carrying capacity and voltage drop together with the installation conditions. Connector ratings, cable routing and mechanical protection must also suit the application.
Clear identification and practical cable routes make deployment, inspection and fault finding more straightforward.
IMPORTANT DISCLAIMER
This section provides a general framework for building power grids and should be used as a reference. Always consult a certified professional for implementation.
This guide is for educational purposes only. The design and realisation of an electrical power grid should always be evaluated and implemented by a qualified professional, ensuring compliance with local laws and safety standards.
LET’S DEFINE THE RIGHT DISTRIBUTION FOR YOUR APPLICATION.
Tell us about your power source, connected equipment and operating environment. Our engineers can help identify suitable distribution units, cable assemblies and configuration requirements.