Electrical

CEIG Approval for a DG Set: When It Applies, Drawings and the Inspection

Name: Secured Engineers Private Limited — Noida (Delhi NCR)
Address: Supertech, Astralis Supernova, Sector 94, Noida, Uttar Pradesh, 201301, IN
Telephone: +91 70099 85817

22 October 2026 · 5 min read · by Secured Engineers Editorial Team

Title card reading CEIG Approval for a DG Set: When It Applies, Drawings and the Inspection. — Title card. Not a photograph of a Secured Engineers site.

A DG set needs the Electrical Inspector's inspection before it is commissioned when its capacity is above the limit your state has notified, or when the installation it feeds is above the voltage your state has notified. Below those limits the owner inspects, tests and self-certifies. Both thresholds are set by the state, not by one national figure, so confirm them before you plan the schedule.

When does a DG set need CEIG approval?

The Central Electricity Authority (Measures relating to Safety and Electric Supply) Regulations, 2023 split the question into capacity and voltage, and leave the numbers to the appropriate government, in practice the state. The Chief Electrical Inspector to Government (CEIG) and the Electrical Inspector are the officers who carry out the inspection.

Question	What the 2023 regulations say	Who sets the number
Which generating units are inspected before commissioning?	Regulation 34: units above the capacity notified by the appropriate government, including units using renewable sources.	The state
Which installations are inspected by the inspector?	Regulation 45(2) and (3): installations above the notified voltage, and all apparatus of generating units above the capacity under regulation 34, before supply starts or restarts after a shutdown of six months or more.	The state
What about installations at or below the notified voltage?	Regulation 45(1)(a): inspected, tested and self-certified by the owner, with the report sent to the inspector in the Schedule II forms; the owner may instead choose inspection by the inspector.	Owner, on the state's notified voltage
Later changes	Regulation 45(6): an addition or alteration is not to be connected until approved in writing by the inspector or self-certified, as the case may be.	The state's thresholds
Periodic inspection	Regulation 32: by the inspector above the notified voltage, self-certified below it; periodicity as directed by the state, not exceeding five years.	The state, within the five-year cap

States describe this differently on their portals. Our Haryana page records the department's procedure note that for installations above 500 kVA the single-line diagram, with a building plan showing transformer, generator, HT and LT protection and earth pits, is approved before work starts. Our Himachal Pradesh page records that a standby DG set needs the utility's NOC, applied for within the online Form A. For Punjab, Uttar Pradesh and Delhi, the departments list DG sets among their online inspection services, and thresholds should be confirmed there; see the multi-state CEIG guide.

What must the installation itself satisfy?

The regulations impose design duties that the drawings must show. These are the ones most relevant to a DG set.

Earthing. Regulation 43 asks that the neutral point of every generator and transformer be earthed through not less than two separate and distinct connections. For apparatus above 250 V and up to 650 V, the frame of every generator is to be earthed by two separate connections, and earthing systems must be tested before energising. Earth fault loop impedance must allow the protective device to operate in time. See earthing and lightning protection compliance.
Residual current device. Regulation 44 requires use of electricity in an installation to be controlled by a residual current device, subject to its provisos.
Interlocks and back-feed. For installations above 650 V, regulation 47 requires that supplies not meant to run in parallel have their breakers interlocked against inadvertent paralleling or back-feed, and that parallel generators using neutral switching are interlocked so the generator breaker cannot close unless a neutral is connected to earth. Apply the same discipline to a low-voltage changeover.
Generator protection. At voltages above 650 V, regulation 47 requires earth fault or leakage protection on all generators of 100 kVA and above, and winding-fault protection (restricted earth fault or differential) on generators of 1,000 kVA and above.
Exhaust. Section 14 of the Factories Act requires the exhaust of a stationary internal combustion engine in a factory to go to the open air.
Fuel and emissions. Diesel storage may fall under the petroleum rules, see PESO licence for diesel storage and tank distances, and emissions are covered in CPCB IV+ norms for DG sets.

Which drawings and documents go in the file?

The inspector assesses how the set is integrated, because the generator itself arrives with its own test certificates. Regulation 48 allows the inspector to ask for the manufacturer's type, acceptance and routine test certificates if required, and the file should be ready with them. Our guide to what the inspector checks on DG sets covers the pattern in detail.

Single-line diagram. The set, the changeover, the main board and the loads, with protection ratings and settings, not just connectivity.
Layout drawing. The DG room or yard with clearances, access, exhaust route and fuel tank position.
Earthing design. The neutral and body earthing, electrode design and measured resistance values.
Cable sizing calculations. Current and voltage drop for the DG-to-panel run.
Changeover and interlock details. How back-feed to the utility is prevented.
Load schedule. What the set feeds and how it was sized; the DG sizing calculator gives a first check.
Manufacturer's certificates and site test records. Insulation resistance, earth resistance and protection tests.

Where the DG parallels with other sources, see DG synchronisation failures and solar with DG sets.

What happens at the inspection?

The inspector compares the file with the site. Regulation 48 says the inspector may require tests before or after the installation is charged, and that records of tests, trippings, maintenance and repairs be kept so they can be compared with earlier records. Insulation resistance is tested before reconnection under regulation 42. Expect to demonstrate the earthing values, the protection operating on injection or simulated fault, the changeover and interlock, the emergency stop, and a load run. Where the file and the site disagree, the site is what is inspected, and the deviation stalls energisation.

Which mistakes delay approval?

Buying and positioning the set before the single-line diagram, so the changeover and cable route are worked out around a fixed machine.
Showing earthing as a symbol or note on the diagram.
Leaving the file until the plant is otherwise ready, putting approval on the critical path of energisation.
Letting the site drift from the approved drawing and not updating it.

The CEIG readiness calculator runs a pre-filing checklist, and the glossary entry defines the term.

How Secured Engineers helps

Secured Engineers designs electrical systems in-house, and files Fire NOC, CEIG and DISCOM net-metering applications in-house. It prepares the single-line diagram with protection settings, the earthing design and the cable calculations the inspector reviews, files, answers queries and attends the inspection. MEPF and solar can sit under one contract. The company works from offices in Noida (Delhi NCR) and Ludhiana, with 535+ projects across 18+ states and 89.77% repeat clients.

If you already have a DG file, we can review it before it goes in. Start from our CEIG approval consultancy, send the diagram and layout on WhatsApp, call +91 70099 85817, or ask for a free proposal.

Frequently asked

Does every DG set need CEIG approval?

No. Regulation 34 of the CEA 2023 safety regulations leaves the capacity above which a generating unit must be inspected by the Electrical Inspector before commissioning to a notification by the appropriate government, which in practice is your state. Below that capacity, the installation it feeds may still need inspection if it is above the state's notified voltage. Look up both numbers for your state, or ask the inspectorate, before you decide.

What happens if my DG installation is below the thresholds?

Under regulation 45, an installation at or below the notified voltage is inspected, tested and self-certified by the owner or consumer before supply, and the self-certification report is submitted to the Electrical Inspector in the prescribed form. It counts as received if not acknowledged within three working days, and the owner may choose to have the Electrical Inspector inspect it instead. Self-certification is still a legal record, so the tests have to be real.

Which documents does the inspector expect for a DG set?

A single-line diagram showing protection ratings and settings, the earthing design with measured values, a layout with clearances and access, cable sizing calculations, details of the changeover and interlocks that prevent back-feed, the equipment's manufacturer test certificates where required, and a load schedule. Files stall most often when the diagram shows connectivity only, or when earthing appears as a note rather than a design.

Does the DG exhaust have to go outside the building?

Yes. Section 14 of the Factories Act says no stationary internal combustion engine may be operated in a factory unless the exhaust is conducted into the open air, and no other internal combustion engine may be operated in a room unless effective measures prevent accumulation of harmful fumes. Plan the exhaust route, silencer and stack height with the room layout, and separately check the emission norms that apply to the set.

Can a DG set feed power back to the grid?

Not unless it is designed and permitted to run in parallel. Regulation 47 requires that where supplies are not meant to run in parallel, their breakers or linked switches are interlocked to prevent inadvertent paralleling or back-feed, and it asks for an interlock where generators in parallel use neutral switching. A mechanical or electrical interlock on the changeover is the usual answer; paralleling with the DISCOM needs its separate permission.

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