Key stages of an industrial electrical infrastructure project: load balance, selectivity, earthing arrangement and integration with existing processes.
Introduction
A custom electrical installation for an industrial site is never a catalogue exercise. Every plant has its own load mix, its own operating rhythm, its own constraints on availability and safety, and its own trajectory of future evolution. A well-designed installation reflects all of that from day one, instead of being adjusted later at higher cost.
This article walks through the engineering path we follow — from initial site analysis to commissioning and documentation — and highlights the design choices that most influence long-term reliability and maintainability.
Why this topic matters
An industrial electrical installation is a system, not a collection of components. Decisions taken at the architecture stage — the LV switchboard layout, selectivity strategy, earthing arrangement, segregation of critical circuits — dictate how the plant will behave for the next 20 to 30 years.
Weak upfront engineering typically shows up as recurrent nuisance trips, poor selectivity, difficulty extending the installation, painful maintenance windows and unnecessary energy losses. All of these can be avoided, but only if the right questions are asked at the right time.
Technical context
The starting point is a rigorous site analysis. We walk the site, review the existing single-line diagram if one exists, inventory the loads (nominal, starting, cyclic), and identify the environmental constraints: temperature, humidity, dust, vibration, hazardous zones.
This is followed by a formal load assessment: individual and aggregated demands, simultaneity factors, motor starting behaviour, power quality profile. On brownfield sites, we also review the existing infrastructure — transformer capacity, cable ways, switchboards, protection settings — to understand what can be retained, reinforced or replaced.
From there, the electrical architecture takes shape: main LV switchboard (TGBT), sub-distribution boards, motor control centres, dedicated boards for critical loads, and the routing strategy for cable trays and busways.
Key engineering considerations
Several design axes deserve particular attention on industrial projects:
- Selectivity between protection devices — time-based, current-based or logical — so that a downstream fault trips only the closest device.
- Earthing arrangement (TT, TN, IT) chosen for the site's continuity, safety and maintenance requirements rather than by habit.
- Segregation of critical circuits from general-purpose circuits, with dedicated feeders and, where relevant, an emergency bus.
- Short-circuit withstand of the switchgear, coordinated with the upstream transformer and cable characteristics.
- Cable sizing that accounts for load growth, harmonic content and installation conditions, not only steady-state current.
- Operational constraints: shift patterns, cleaning cycles, hazardous zones, and any process that cannot tolerate a shutdown.
Practical recommendations
Design the TGBT and sub-boards with spare ways from the outset. Adding capacity later is always more expensive than reserving it upfront.
Instrument the installation. Sub-metering at the main departures — and, where load matters, at machine level — turns the electrical system from a black box into a manageable asset. It is also the foundation for any future energy optimization work.
Separate power routing from data and control routing. Cable ways that respect segregation rules reduce interference, simplify troubleshooting and make future extensions cleaner.
Plan the commissioning phase seriously. Insulation tests, continuity tests, protection setting verification, selectivity checks and functional trials on the critical circuits are not paperwork — they are the moment the installation earns its operational credibility.
Deliver structured as-built documentation: single-line diagram, switchboard layouts, cable schedules, protection settings, test reports and a maintenance plan. This is what makes the installation supportable by any competent team over its lifetime.
Common mistakes to avoid
Sizing the installation to today's exact load leaves no headroom for evolution and forces expensive rework at the first extension.
Choosing an earthing arrangement by default, without discussing continuity of service and maintenance workflow, is a decision the operator will live with for decades.
Skipping selectivity coordination — or relying on generic factory settings — creates cascading trips whose root cause is hard to explain and easy to blame on the wrong equipment.
Neglecting documentation is not a saving. Every hour saved at handover is paid back with interest during the first serious incident.
How EOS approaches this topic
We treat each industrial installation as a bespoke engineering problem. Our teams combine site analysis, load engineering, architecture design, protection studies and commissioning under a single technical responsibility, which keeps the intent consistent from the single-line diagram to the last connection.
We also design for the people who will operate the installation: clear labelling, coherent switchboard layouts, accessible protection settings, and documentation that stays useful long after handover.
Related solutions
The following EOS solutions cover the topics discussed above and are frequently combined on the same project.
Discuss your project
If you are planning a new industrial site, reconfiguring an existing one, or preparing a major process change, our engineers can help structure the electrical design decisions at the right level of detail.