In short. A campus is several facilities behind one name, and each zone deserves its own backup strategy. Laboratories, examination halls, data rooms and hostels have real interruption consequences; classrooms and sports facilities usually do not. Plan the generator arrangement by zone and distribution path, put UPS where tolerance is low, size on the retained loads and their motor starts, and align testing and maintenance with the academic calendar rather than the supplier’s convenience.
One institution, many power profiles
A school in Secunderabad, an engineering college on the outskirts of Hyderabad and a residential university campus in Andhra Pradesh do not have the same requirement, and even within one campus the requirement changes from building to building. Teaching blocks need lighting, fans and projectors for a few hours a day. Laboratories may hold samples in ultra-low freezers, run fume hoods that are a safety system, and operate instruments that take hours to restabilise. Examination halls running online tests cannot tolerate a flicker. The data room, library systems and campus network are the institution’s administrative backbone. Hostels are occupied overnight, with water pumping, lighting, security and sometimes kitchens. Auditoriums, kitchens, workshops, sports facilities and street lighting complete a list that no single generator can sensibly serve as one load.
The planning error is to treat the campus as one connected load with one interruption tolerance, usually followed by a single large set at the main substation that is either oversized or unable to reach the buildings that matter. The better approach starts with zones.
Zone the campus before you size anything
| Zone | Typical loads | Interruption consequence | Usual strategy |
|---|---|---|---|
| Laboratories and research | Freezers, incubators, fume hoods, instruments, clean rooms | Sample loss, safety, days of recalibration | UPS on instruments, generator within seconds |
| Examination and computer halls | Computers, network, lighting, cooling | Invalidated tests, rescheduling | UPS plus generator during exam windows |
| Data room and network | Servers, switches, telephony, CCTV recorders | Campus-wide loss of systems | UPS plus generator, cooling included |
| Hostels | Lighting, fans, water pumps, security, kitchen refrigeration | Student safety and welfare overnight | Generator with automatic transfer |
| Administration and library | Offices, records, reading rooms | Disruption | Generator, shared with another zone |
| Teaching blocks | Lighting, fans, projectors, some air conditioning | Lost lectures | Partial backup or none |
| Campus services | Water treatment and pumping, sewage, street lighting, gates | Safety and hygiene | Generator, early priority |
| Auditorium, sports, canteen | Event lighting, sound, air conditioning, kitchen | Event disruption | Generator during events or rental |
Zoning answers the architecture question. A compact campus with an HT ring main may best be served by a generator plant at the main substation feeding the essential buildings through dedicated LT feeders. A spread-out campus is often better served by medium sets at the buildings that matter, each with its own AMF panel, which avoids long LT cable runs and lets each zone be maintained independently. Hybrids are common, with a central plant for hostels and services and local sets at laboratories and the data room. The comparison is helped by the power system design guide and the classification method on critical-load classification.
Laboratories deserve special caution
Laboratory backup is not classroom lighting with a different label. Ultra-low freezers at minus 80 degrees Celsius hold years of samples and warm quickly once their compressors stop; they need generator supply within minutes and should be alarmed. Fume hoods and laboratory exhaust are safety systems where hazardous chemicals are handled and should be restored with the first loads. Instruments such as spectrometers, chromatographs and sequencers need a UPS to ride through the transfer and a generator with acceptable voltage and frequency quality behind it. Incubators and growth chambers need both power and the cooling that keeps the room within limits. The laboratory’s own safety officer should define the list, and the generator should be sized for the compressors and fans that start when supply returns. The UPS and generator interaction is covered on UPS and nonlinear loads on generators.
Sizing a zone and the air-conditioning question
Each zone is sized on its retained running load plus the largest motor start, measured where meters exist and estimated from the equipment schedule where they do not. Air conditioning is often the largest consumer in a modern campus building and can represent a large share of demand in the Telangana summer; whether it goes on the generator should be decided by zone, retained for data rooms, laboratories, examination halls and perhaps auditoriums during events, and excluded for general teaching spaces.
S_zone = (P_retained / PF) + S_largest-start
In this expression S_zone is the indicative generator kVA for the zone, P_retained is the running kW of its retained loads, PF is the power factor and S_largest-start is the transient kVA of the largest motor start once the base load is connected. For a hostel block with 90 kW of lighting, fans, kitchen refrigeration and security at 0.85 PF and a 22 kW water pump starting direct-on-line, S_zone is about 106 kVA plus about 170 kVA of transient, pointing to a 160 to 200 kVA set, or smaller if the pump is given a soft starter (illustrative). A central plant is the sum of the zones it serves with diversity applied, following the method on generator sizing.
Calendar, hostels and temporary power
The academic calendar drives both demand and access. Examinations, admissions, convocations and hostel occupancy peaks are the times the backup must not fail, so load tests and the annual service should be completed before them and never scheduled during them. Vacations are the window for major work on switchboards and generators. Hostels differ from the rest of the campus because students remain overnight; their sets must start automatically, their water pumps must be on backup, and their alarms must reach a warden or security post. Construction of new blocks, electrical upgrades and large events create short-term requirements that are usually better met by rental sets with temporary distribution than by oversizing the permanent plant; see rental and temporary power.
Record the arrangement as the campus grows. New buildings, a new data room or an expanded laboratory change both the load and the paths through which it is fed, and spare capacity in one zone’s generator cannot be assumed to be available in another unless the distribution connects them. A simple capacity and interface register, reviewed each year, prevents that assumption.
Common mistakes
- Installing one large set at the substation to cover “the campus”. It is oversized for the loads that matter and the LT cable runs to distant hostels and laboratories cannot carry the starting current.
- Treating laboratory supply as ordinary building load. Freezers thaw and fume hoods stop while the set is left to start manually in the morning.
- Scheduling the annual service in examination week. The set is in pieces when an online test depends on it.
- Omitting UPS from examination halls and the data room. Every transfer drops the systems the generator was bought to protect.
- Leaving hostel sets on manual start. Students spend the night without water or light because nobody was on duty to press the button.
What to send us
Send a campus plan with the substation, distribution routes and the buildings to be protected, a zone-wise load list with pump, compressor and air-conditioning ratings, the laboratory equipment that must be held and the UPS already installed, hostel occupancy and the academic calendar’s critical periods, and any existing generator details with nameplate photographs. Send your campus power requirement.
Questions engineers ask
Should a campus have one big generator or several smaller ones?
Usually several, placed at the zones that need them, or a central plant for compact campuses with an HT ring and short LT runs. The decision depends on distances, distribution paths and whether zones must be maintained independently.
What should be on backup in a school?
Water pumps, security and gate systems, the office and server, selected classroom and corridor lighting, the kitchen’s refrigeration and any examination or computer hall. Full air conditioning for all classrooms is rarely justified.
How do we protect laboratory freezers and instruments?
Put instruments on a UPS, put the freezers and fume hoods on a generator with automatic transfer, alarm freezer temperatures to a person, and size the set for the compressors starting together when supply returns.
When should campus generators be serviced and tested?
Service during vacations, load-test before examinations, admissions and convocations, and run a monthly transfer test at a published time. The calendar should drive the maintenance plan.
Is a rental generator sensible for a convocation or construction work?
Yes. Short-term event and construction loads are better met by rental sets with temporary distribution than by enlarging the permanent plant for a few days a year.
Technical content reviewed by Srinivas Reddy, Managing Partner, Reddy Generators. Last updated 19 October 2026.