In short. The right backup-power arrangement for a facility follows from what it does when the supply fails, not from its industry label. A hospital, a cold store and a construction site may all need a 500 kVA diesel generator, but they differ in which loads must stay on, how long an interruption is tolerable, the largest motor start and the hours the set runs each year. The sector pages ask those questions.
Why the sector matters, and why it is not enough
Two factories in the same industrial estate can have the same connected load and need entirely different backup systems. One runs a continuous process where an unplanned stop ruins a batch and restarting takes hours; the other runs discrete machining where an outage costs a shift. The first needs automatic transfer within seconds, controlled restart sequencing and probably a UPS for the control system. The second may be well served by a manually started set and a plan for which machines come back first. The sector tells us which questions to ask; the facility’s own operations give the answers.
We work through the same questions with every customer.
- Which loads must continue, which can pause, and which need a controlled shutdown rather than a sudden stop?
- How long can each group be without power: zero, seconds, minutes or hours?
- What is the largest single starting event, and what else is running when it happens?
- How many hours a year will the set run, which decides standby, prime or continuous rating and the fuel and service budget?
- What does the regulator, the licence or the insurer require, including CPCB IV+ emission norms for new sets and any sector-specific standards?
- What exists already on site: switchgear, earthing, space, fuel storage, UPS, and the DISCOM connection?
How the sectors differ in practice
The table gives the dominant backup-power concern for the main sectors served from Secunderabad, together with the typical consequence of getting it wrong. It is a starting point for the sector pages, not a specification.
| Sector | Dominant concern | Typical tolerable gap | Consequence of a poor design |
|---|---|---|---|
| Data centres and IT | UPS compatibility, N+1 capacity, tested transfer sequence | None at the IT load, seconds for cooling | UPS drops to battery on every transfer, cooling fails before the set is stable |
| Hospitals and healthcare | Life-safety loads, fast transfer, isolated supplies in clinical areas | Under 10 to 15 seconds for essential circuits | Theatres and ICUs lose power beyond the UPS bridge, regulatory failure |
| Pharma and laboratories | Cleanroom HVAC, cold chain, validated systems | Minutes for HVAC, none for monitoring | Lost batches, environmental excursions that must be reported |
| Manufacturing | Motor starting, process restart order, power factor | Seconds to minutes depending on process | Set stalls on the first compressor start, process restarts in the wrong order |
| Cold storage and food | Compressor starting, temperature hold time, long runs during load shedding | Minutes, set by product temperature | Product loss, set under-sized for simultaneous compressor restarts |
| Commercial buildings | Lifts, fire pumps, essential lighting, diversity of tenant load | Seconds for life safety, longer for comfort | Fire pump cannot start on the set, lifts trapped between floors |
| Construction and infrastructure | Prime-rated duty, mobility, harsh conditions, fuel logistics | Not applicable, the set is the supply | Set rated for standby runs prime and wears out in a year |
| Telecom and remote sites | Unattended reliability, fuel autonomy, remote monitoring | None, bridged by batteries | Site goes dark because no one knew the set had failed to start |
The detailed treatment for each sector begins with data centre power, healthcare and hospital power, manufacturing power, cold-storage power, commercial building power and construction and infrastructure power, with further pages for pharmaceuticals, telecom, mining, water and the other sectors listed in the menu.
Look beyond the visible load
The load that the customer names is rarely the whole load. A production line depends on compressed air from a compressor house in another building, cooling water from a pump house, and a control room with its own UPS. A server room depends on the chillers, the pumps and the air handlers. A cold store depends on the condenser fans as much as the compressors. If the generator energises the machine and not the service it relies on, the machine still stops. Tracing these dependencies is the most common gap we find in installations that have never performed as expected.
Classify, then size
Once loads are listed and their dependencies traced, they are sorted into classes: life-safety, process-critical, restart-critical, deferrable and non-essential. Sizing proceeds from the classes that will actually be on the set, not from the connected total. For a factory with 1,200 kW connected where only 450 kW is process-critical and essential, the set is sized around 450 kW plus the largest starting event and a growth allowance, and the rest is shed on transfer. That decision frequently halves the capital cost and improves reliability, because a lightly loaded oversized set has its own problems. The method, including the treatment of shed loads, is explained in generator sizing.
Duty rating follows hours
A facility that expects the DISCOM to fail for a few hours a month needs a standby-rated set. A construction site, a remote telecom tower or a plant facing scheduled load shedding of several hours a day needs a prime-rated set, which for the same engine means a lower nameplate and a higher service budget. The hours assumption should be written into the enquiry.
Integration is sector-specific too
The transfer arrangement, the earthing, the fuel system and the controls differ by sector as much as the set does. A hospital may need separate transfer switches for life-safety and equipment branches and a closed-transition return so that clinical loads are not disturbed twice. A data centre needs the set to be proven against the UPS input and the cooling restart, not against a resistive load bank alone. A factory with large motors may need a soft starter or a staggered restart scheme rather than a bigger set.
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Common mistakes
- Sizing the set from the connected load or the sanctioned demand. The result is a set two to three times larger than needed, running at 20 percent load, wet-stacking and costing more to service.
- Backing up the machine but not the service it depends on. The line is energised and still stops because the compressor house is dark.
- Choosing a standby rating for a site that will run several hours a day. The engine reaches overhaul in a fraction of its expected life and warranty claims are refused.
- Ignoring the largest starting event. A set that carries the running load comfortably stalls or trips when the first large compressor or pump starts.
What to send us
Send the facility type and location, a load list or at least the main equipment with motor ratings and starting methods, the hours of outage you experience or expect each month, the existing switchgear and DISCOM connection details, and a note on which operations must continue and which can stop. Photographs of the main panel and the proposed generator location help. Start with the application engineering enquiry and we will route it to sales, rental or service as the answers dictate.
Questions engineers ask
How do I know what size generator my facility needs?
List the loads that must run during an outage, trace their supporting services, add the largest motor start, allow for growth, and size the set on that total rather than on the connected load. A load study with clamp-meter measurements over a working week is the most reliable basis and usually shows a smaller requirement than the nameplates suggest.
Should a factory in Telangana buy a standby or prime rated set?
If outages are occasional and short, standby. If the set will run scheduled hours most days, as during load shedding or at a site with no grid, prime. The same engine carries a lower prime rating, so a prime duty needs a larger set and a bigger service budget. State the expected hours and let the rating follow.
Do I need a UPS as well as a generator?
Only for loads that cannot tolerate the 10 to 20 seconds a diesel set takes to start and accept load. Servers, control systems and medical equipment usually do; motors, lighting and HVAC usually do not. The UPS bridges the gap and the generator carries the duration.
Does the sector change which emission norms apply?
No. CPCB IV+ norms apply to new diesel generator sets up to 800 kW regardless of the industry, and state pollution control board consent conditions apply to the installation. Sector regulations add requirements on top, for example for hospitals and pharmaceutical plants, but they do not relax the emission norms.
Technical content reviewed by Srinivas Reddy, Managing Partner, Reddy Generators. Last updated 19 October 2026.