# Electrical Works — HT/LT Panels, Distribution and Wiring

> Electrical works on a commercial or industrial building cover HT and LT panels, power distribution, cabling, wiring, earthing and small power, from the load schedule through testing. The load calculation comes first because it fixes the sanctioned load, transformer, cable sizes and panel ratings, all of which are expensive to change later.

## What we deliver

**HT and LT panels, power distribution, cabling, wiring, earthing and small
power** for commercial, industrial and institutional buildings — from the load
schedule through testing and handover.

Electrical is the service every other system depends on. HVAC, firefighting
pumps, lighting, lifts, IT and security all draw from the same distribution, so
the decisions made at load-calculation stage quietly shape the whole building.

## Scope of works

| Stage | What we deliver |
| --- | --- |
| Load assessment | Connected load, diversity, sanctioned load application support |
| Design | Single-line diagram, cable and panel sizing, discrimination |
| HT side | HT panel, transformer interface where in scope |
| LT side | Main LT panel, sub-distribution boards, busbar risers |
| Cabling | Cable laying, containment, glanding, termination |
| Final circuits | Wiring, small power, lighting circuits, floor boxes |
| Earthing | Earth pits, bonding, lightning protection interface |
| Testing | Insulation resistance, earth resistance, polarity, commissioning |

## What drives the cost

Connected load and diversity · HT supply versus LT-only · transformer and DG
interface · cable lengths and routes · containment type · panel make and form of
separation · number of final circuits and floor boxes · testing and documentation
requirements.

## Where projects go wrong

- **No realistic load schedule.** Everything downstream — sanction, transformer,
  cables, panels — is sized off it.
- **Cables sized for current but not for voltage drop.** Long runs in large
  buildings need upsizing that a simple current check misses.
- **Discrimination not checked.** A fault on one circuit trips the upstream
  breaker and takes out a whole floor.
- **Earthing done to a minimum and never tested.** It degrades, and it is the
  component that makes faults safe.
- **Containment sized exactly for day one.** The next change becomes a rebuild.

## Why Hagerstone

**15 electricians in-house**, with MEP delivered alongside interiors, facade,
civil and PEB — so the electrical design is coordinated with the layout, the
ceiling and the HVAC rather than retrofitted to them.

**Owned tooling** including measuring instruments, crimping tools and testing
equipment, under ISO 9001 / 14001 / 45001 and 79+ quality checkpoints.

For air conditioning, see our [HVAC services](/services/hvac).

## Standards referenced

Installation safety under the **CEA (Measures relating to Safety and Electric
Supply) Regulations, 2023**. Wiring practice to **IS 732**. Earthing to
**IS 3043**.

## Frequently asked questions

### What is the difference between HT and LT panels?

HT panels handle the high-tension supply coming in from the utility, typically at 11kV, and feed the transformer. LT panels take the stepped-down supply, normally 415V, and distribute it across the building to sub-distribution boards and final circuits. A small commercial floor may only ever see the LT side; a factory or a standalone building with its own transformer needs both.

### Why does load calculation matter before anything is installed?

Because it fixes the sanctioned load you apply for, the transformer and cable sizes, and the panel ratings — and all of those are expensive to change afterwards. Undersizing means an upgrade application and a rebuild; oversizing means paying demand charges and capital for capacity you never use. A realistic load schedule with diversity applied is the first electrical deliverable, not an afterthought.

### Is earthing really that important on a commercial fit-out?

Yes. Earthing is what makes a fault safe instead of lethal, and it protects sensitive IT and electronic equipment. It also degrades — soil dries, connections corrode — so earth resistance should be tested at installation and periodically after. It is inexpensive to do properly and one of the most common defects found in older installations.

## Sources

- [CEA (Measures relating to Safety and Electric Supply) Regulations, 2023](https://cea.nic.in/regulations/notified-regulations?lang=en) — Safety of electrical installations
- [IS 732](https://standards.bis.gov.in/website/published-standards/department-wise) — Code of practice for electrical wiring installations
- [IS 3043](https://standards.bis.gov.in/website/published-standards/department-wise) — Code of practice for earthing

---

Source: https://hagerstone.com/services/mep/electrical-works-ht-lt