TNB Substation for a Factory: When You Need One, Compact vs Indoor, Land, Cost and Timeline

Key Takeaways

• Under TNB's Electricity Supply Application Handbook (ESAH 3.1), a factory with maximum demand above 350 kVA (about 505A at 400V) must be fed from a new substation. From 1,000 kVA (about 1,440A), supply moves to 11kV and you own the transformers.
• Between 100 kVA and 350 kVA (about 145A to 505A), TNB decides after a system study. Any load above 100A must be applied for by a BEM-registered Electrical Consultant Engineer.
• A TNB compact substation for industry goes up to 1,000 kVA on a plot of about 7.0m x 4.0m. An indoor substation building is 7.6m x 5.7m (single chamber) or 10.6m x 5.7m (double).
• The substation land goes to TNB for a nominal RM10, and TNB may use it to supply neighbours. Connection charges run from RM4,050 to RM38,250 for low-voltage loads of 61kW to 850kW, and RM45 per kW of declared demand at medium voltage.
• TNB's typical lead time is 3 to 12 months for 400V with a new substation, 6 to 12 months at 11kV and 18 months to 2 years at 33kV.

A factory needs its own TNB substation when its declared maximum demand is more than the nearby low-voltage network can carry. TNB's handbook draws the line above 350 kVA (about 505 amps at 400V), where supply must come by direct cable from a new substation; from 100 kVA to 350 kVA, TNB decides case by case after a system study. Above 1,000 kVA (about 1,440 amps), the factory takes 11kV supply and owns its own transformers.

Where the rules come from

Two TNB documents govern this in Peninsular Malaysia: the Electricity Supply Application Handbook, Version 3.1 (ESAH, the current edition on TNB's website), which sets supply schemes, substation types, land sizes and lead times; and the Connection Charge Book (2025 edition, terms approved by the Energy Commission from 15 January 2021), which sets what you pay. Where they say "subject to system capability study by TNB", the final answer for your site comes from TNB through your consultant.

When does a factory need a TNB substation?

TNB plans supply around maximum demand (MD), the highest load your factory draws, declared in kVA or kW. Buyers and tenants talk in amps, so the table converts each ESAH band to amps at 400V three-phase (amps = kVA x 1,000 / (1.732 x 400)).

Maximum demand (ESAH Table 3-1)	Approx. amps at 400V	Supply voltage	Minimum supply scheme
Up to 100 kVA (non-domestic)	Up to about 144A	400V	Cable from the existing low-voltage network, subject to TNB study
Above 100 kVA to 350 kVA	About 145A to 505A	400V	Underground cable from a feeder pillar or a new or existing substation, subject to TNB study
Above 350 kVA to 1,000 kVA	About 505A to 1,440A	400V	Direct underground cable from a new substation
1,000 kVA to below 5,000 kVA	Above about 1,440A	11kV	Fed through a TNB 11kV switching station; land for a main distribution substation (PPU) may be needed
5,000 kVA to 25,000 kVA	n/a	33kV	Fed through a TNB 33kV switching station; land for a main intake (PMU) may be needed
25,000 kVA to below 100,000 kVA	n/a	132kV or 275kV	Fed from a TNB 132kV or 275kV substation

(A 22kV scheme also exists but is being phased out for 33kV.) Three practical points follow:

1. About 500A is the real dividing line. Below 350 kVA, TNB may supply you from what is already in the street. Above it, you need a new substation, so land and a building become part of your project.
2. About 1,440A ends low-voltage supply. The charge book says loads above 1,000 kVA (850 kW) must take medium voltage, so you buy and maintain your own 11kV switchgear and transformers.
3. 100A changes who applies. Up to 100A, a registered electrical contractor applies on the myTNB portal. Above 100A, an Electrical Consultant Engineer registered with the Board of Engineers Malaysia (BEM) must apply.

TNB requires a power factor of at least 0.85 below 132kV, so 1,000 kVA carries about 850 kW of real load. To turn a machine list into amps and kVA, use the factory power calculator. For typical amperage by industry and how to read an existing supply, see our TNB amperage guide for factories.

Compact substation vs indoor substation vs pole-mounted

The ESAH splits distribution substations (Pencawang Elektrik, PE) into conventional and compact designs. Typical TNB distribution ratings are 300, 500, 750 and 1,000 kVA.

Type	What it is	Limit or note (ESAH 3.1)	Land or building (Table 3-3)
Compact substation, 11/0.4kV	Factory-built kiosk on a plinth, often called a CSU or package substation	Up to 1,000 kVA for commercial and industrial use (500 kVA for housing), subject to a matching metering kiosk	Land about 7.0m x 4.0m
Indoor, single chamber	TNB equipment in a permanent standalone building	Per TNB's Substation Design Booklet	Building 7.6m x 5.7m
Indoor, double chamber	Two transformer chambers in one building	Conventional design	Building 10.6m x 5.7m
Attached substation	Substation room in or against your factory	Needs TNB-certified fire suppression and thermostat exhaust fans	Room to TNB layout
Outdoor pole-mounted	Transformer on poles on an overhead network	Listed as an outdoor conventional type; no land size given, check with TNB	n/a
11kV main switching station (SSU)	TNB switch room that feeds a large consumer's own substation	For 11kV supply customers	Building 7.6m x 5.7m

Compact units are TNB's standard for new developments, but the ESAH rules them out, in favour of an indoor substation, at sites marked for circuit breakers, places with more than two 11kV feeders, MSC status areas and inside attached substation buildings. They must sit near the load centre, away from a development's corners and from sewerage plants.

Bigger loads need much more land: about 30m x 30m for a 33kV switching station, 46m x 46m for a 33/11kV PPU, and 60m x 80m to 160m x 150m for a 132kV PMU. These exclude setbacks: on federal and state roads JKR requires 20.1m from the road centre plus 15.0m for a service road, and local authorities typically require a 6.1m building line.

Land and building you must give TNB

• Above 60 kW, you provide the land. The charge book says a load above 60 kW (about 100A) must provide land for a distribution substation (PE) and, where needed, a PPU. At 60 kW or below, TNB may still ask if the nearest substation cannot carry the load.
• Transfer or lease for RM10. The land is transferred or leased to TNB at a nominal RM10. Without an issued title, you give TNB a 12-month bank guarantee, renewed until the transfer or lease is registered.
• You build it, TNB equips it. You build the substation to TNB's specification and hand over its Certificate of Completion and Compliance (CCC); TNB installs and commissions the equipment.
• TNB can use it for others. The ESAH states that TNB has the right to use the substation to supply other consumers.

If you are buying industrial land in Port Klang to build, put the substation in the layout from day one. A 7m x 4m compact plot is small; a road setback or a 33kV switching station is not.

Who pays what: connection charge and capital contribution

What many still call a "capital contribution" is now the connection charge: a load charge on your declared MD, plus cable charges if the nearest supply that can meet your load is over 6km away, plus the full cost of special requests.

Low-voltage CT-metered supply, where the substation land and building go to TNB at RM10 or no substation is needed:

Declared MD	Approx. amps (0.85 PF, 400V)	CT ratio	Connection charge
61 to 90 kW	104A to 153A	150/5	RM4,050
91 to 120 kW	155A to 204A	200/5	RM5,400
121 to 180 kW	205A to 306A	300/5	RM8,100
181 to 240 kW	307A to 408A	400/5	RM10,800
241 to 360 kW	409A to 611A	600/5	RM16,200
361 to 480 kW	613A to 815A	800/5	RM21,600
481 to 600 kW	817A to 1,019A	1000/5	RM27,000
601 to 720 kW	1,021A to 1,223A	1200/5	RM32,400
721 to 850 kW	1,224A to 1,443A	1500/5	RM38,250

Medium voltage (11kV, 22kV, 33kV) is RM45 per kW of declared MD, so declaring 2,000 kW means a load charge of RM90,000 before extras. High voltage (132kV and above) uses TNB's "first principle" method: you cover the gap between TNB's project cost and 15 years of electricity revenue. An upgrade pays the difference between the new and existing load charge.

On top of the connection charge, the applicant pays for:

• The substation land (transferred for RM10, but lost to you) and the building or compact plinth.
• Cable trenching to your main switchroom and the metering panel. TNB lays service cable up to 30m from its 11kV or 33kV substation; beyond that you pay (for example RM149 per metre for 240mm² 11kV underground cable).
• At 11kV and above, your own switchgear, transformers and protection.
• TNB-certified fire suppression for an attached substation.
• Special requests or local authority conditions beyond TNB's standard, such as horizontal directional drilling or a second dedicated feeder.
• Consultant and contractor fees, and a deposit of about two months' bill (bank guarantee encouraged above RM2,000).

Medium-voltage customers carry two post-supply risks. The Connected Load Charge (CLC) runs for 6 years after a new connection (5 after an upgrade): if recorded MD falls below the reference (85% of the declared yearly MD in years 1 to 4, 75% of the final MD in years 5 and 6), TNB charges RM8.50 per kW of shortfall each month. Declaring 2,000 kW and running 1,200 kW in year 5 is a 300 kW shortfall against 1,500 kW, or RM2,550 that month. Liquidated damages apply if you fail to take supply or terminate within 5 years. Do not over-declare.

How to apply: step by step

For loads above 100A, ESAH runs two parts. In Part A, your development plan goes to the local authority or One Stop Centre; TNB comments within up to 14 days per stage and agrees the substation number, size and location with your consultant. Part B is the TNB application:

1. Appoint one BEM-registered Electrical Consultant Engineer by letter.
2. The consultant applies via the myTNB portal and the local TNB office with the ESAH Appendix 4 checklist: total load in kW, site plan with the substation site, substation layout, single line diagram, switchroom layout, motor loads, power quality declaration, Borang A for the substation land and the title copy.
3. TNB checks the documents and runs a system study.
4. A joint meeting fixes the substation, cable route and metering.
5. TNB issues a Notice of Connection Charges and you pay.
6. Large projects may sign an Electricity Infrastructure Agreement.
7. You complete and hand over the substation; TNB installs and commissions the equipment.
8. Your Energy Commission-registered electrical contractor applies for the meter.
9. TNB energises supply.

Typical TNB lead times (ESAH 1.3.5), assuming no delay in local authority approval:

Voltage level	Typical supply project lead time
400V and below, no substation	Less than 3 months
400V and below, with substation	3 to 12 months
11kV	6 to 12 months
33kV	18 months to 2 years
132kV and above	3 to 5 years (fast track 12 to 24 months on conditions)

Checklist: buying or renting a factory with a substation

The question is not "is there a substation?" but "whose is it, how big is it, and how much of it is mine?"

• TNB or consumer substation? A TNB substation (PE) holds TNB's transformer on land handed to TNB, and you take low-voltage supply metered at your switchboard. A consumer substation belongs to an 11kV or 33kV customer, who owns and maintains the transformers and switchgear.
• Title and land area. Check the title for a transfer or lease to TNB, and whether the land area sold includes the substation plot.
• Approved capacity, not hardware. Get the TNB bill (tariff and 12 months of recorded MD), the meter CT ratio, the main breaker rating and, at 11kV, the transformer nameplates. A 1,000 kVA transformer next door does not mean 1,000 kVA is approved for your unit.
• Shared substation. A TNB substation on your lot may feed neighbours. Only a TNB system study, applied for through a consultant, confirms what more you can get.
• Remaining CLC. At 11kV, a change of tenancy continues the previous consumer's CLC period if it is still running. Ask for the connection date and declared MD.
• Operation. An 11kV consumer substation needs Energy Commission-certified competent persons, such as a high-voltage chargeman (categories B0 to B4). Check who holds the role and the maintenance records.
• Lease terms. Agree in writing who pays for any upgrade; a tenant who funds a substation cannot take it away.

If you need 1,000A or more, start from units that already have it: high-power factories for sale in Selangor, high-power factories for rent, or search factories by specs. Industry checklists, such as for a plastic injection moulding factory, are in our factory requirements by industry pages, and data centre loads are in how many amps a data centre needs. If nothing listed fits, we can find the factory for you.

Running cost matters as much as capacity: our TNB tariff 2026 guide for factories explains industrial rates, Time of Use, maximum demand and the AFA surcharge with worked examples.

FAQ

At how many amps does a factory need its own TNB substation?

Under ESAH 3.1, a factory with maximum demand above 350 kVA, about 505A at 400V, must be fed by direct cable from a new substation. Between 100 kVA and 350 kVA (about 145A to 505A), TNB decides after a system study. Above 1,000 kVA, about 1,440A, supply moves to 11kV with your own transformers.

What is a TNB compact substation and how large can it be?

It is a factory-built 11/0.4kV kiosk on a plinth, TNB's standard for new developments. For industrial use it goes up to 1,000 kVA, subject to a matching metering kiosk, on about 7.0m x 4.0m of land.

How much land must I give TNB for a substation?

About 7.0m x 4.0m for a compact substation, or a 7.6m x 5.7m (single chamber) or 10.6m x 5.7m (double chamber) building for an indoor one, plus setbacks. A 33kV switching station needs about 30m x 30m. The land is transferred or leased to TNB for a nominal RM10.

How much does a TNB substation cost a factory owner?

TNB's connection charge for low-voltage CT-metered supply runs from RM4,050 (61 to 90 kW) to RM38,250 (721 to 850 kW); medium voltage is RM45 per kW of declared maximum demand. You also pay for the substation land and building, cabling, special requests and, at 11kV, your own transformers and switchgear.

How long does TNB take to supply a new factory substation?

TNB's typical lead time is 3 to 12 months for 400V supply with a substation, 6 to 12 months at 11kV and 18 months to 2 years at 33kV. These assume no delay in local authority approvals.

What is the difference between a TNB substation and a consumer substation?

A TNB substation holds TNB's equipment on land handed to TNB, which TNB may also use to supply neighbours, and you take metered low-voltage supply. A consumer substation belongs to a medium-voltage customer, who owns, operates and maintains the transformers and switchgear with Energy Commission-certified competent persons.

Buying or renting, talk to us

FactoryHub is the industrial-only platform of Peter Tan (REN 12771) and Jason Low (PEA 1478), registered with BOVAEP under CID Realtors Sdn Bhd E(1) 1855. We handle both rent and sale, and we co-broke across the whole market, so if the right unit is another agent's listing we will still put it in front of you.

Send us the numbers that decide the shortlist: required amps, built-up area, floor loading, preferred area and target date. We reply with what actually exists, including units that are not advertised publicly. For 800A to 4,000A+ requirements, see high-power factories in Selangor.

Agent	Licence	Mobile / WhatsApp	WeChat
Peter Tan	REN 12771	+6016-666 6872	peterindustrial
Jason Low	PEA 1478	+6012-288 1834	massiveaction

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