LT vs HT Distribution
LT vs HT distribution is the choice between taking supply at low tension (415 V, directly usable) and high tension (typically 11 kV, stepped down by your own transformer) — a threshold set by load size, DISCOM rules and tariff economics.
Why it matters on an MEPF project
Beyond a load threshold (DISCOM-specific), consumers move to HT supply: you own a transformer, an HT panel and the CEIG-approved substation that comes with them. In exchange, HT tariffs are generally kinder per unit, losses are billed differently, and your internal distribution gains headroom for growth. The crossover is an economics-plus-obligation decision, not a status upgrade.
The obligations are real: HT installations sit squarely inside the Electrical Inspectorate regime (CEA Safety Regulations 2023) — approval before energisation, periodic inspection, qualified operation. Facilities that grew past the LT boundary informally, on multiple LT connections, eventually face the consolidation conversation with both the DISCOM and the Inspectorate.
How it's specified in practice
| Parameter | Typical / working position | Governing reference |
|---|---|---|
| Voltage class | LT: 415 V three-phase · HT: 11 kV typical (higher for big loads) | DISCOM supply code |
| Who owns the transformer | LT: DISCOM's · HT: yours (with substation) | supply arrangement |
| Statutory interface | HT: CEIG approval + periodic inspection | CEA (Safety) Regulations 2023 |
| Tariff character | HT generally better ₹/unit with demand-based billing | state tariff order |
Common mistakes
- Stacking multiple LT connections to dodge HT — costlier and eventually unwindable.
- Taking HT without budgeting the substation, protection and compliance ownership.
- Sizing the transformer to today with zero growth headroom.
- Ignoring demand-based billing mechanics after conversion.
Related on this site
One of 68 working definitions in the MEPF & solar engineering glossary. The buying side of the same decisions is in the buyer's guides; the numbers are in the calculators.
Frequently asked
At what load do I need an HT connection?
The threshold is set by your DISCOM's supply code and varies by state. If your sanctioned load is approaching triple digits of kVA, the HT conversation is due — with the tariff order in hand.
What approvals does an HT connection need?
DISCOM sanction and works, plus Electrical Inspectorate (CEIG) approval of your substation before energisation under the CEA Safety Regulations 2023 — drawings, earthing, protection and inspection.
Standards referenced: CEA (Safety) Regulations 2023 · DISCOM supply codes