TNB Tariff Categories Explained (RP4 2025)

A 1,000 kW monthly peak now costs between RM89,270 and RM97,060 a month in demand charges alone, and the tariff letter your finance team has quoted for the last decade no longer exists. Since 1 July 2025, TNB tariff categories for non-domestic customers are defined by supply voltage, not by the old C and E letters. If your bill still gets filed as "we're on C1", that shorthand is now wrong, and it hides the part of the bill that has grown most: the per-kW charges.

This is the reference version. What changed, where each old letter maps, the five components on the new bill, and a worked Medium Voltage example using the published demand rates.

What changed on 1 July 2025?

TNB restructured all non-domestic tariffs under RP4, the fourth Regulatory Period, which runs from 1 July 2025 to 31 December 2027 in Peninsular Malaysia. Three things changed at once.

First, the letter categories (B, C1, C2, E1, E2, E3) were retired. Categories are now named by the voltage at which you take supply. Second, the bill was unbundled from a short list of line items into five distinct components, so you can see separately what you pay for energy, for capacity, for the network, for retail service, and for fuel. Third, the weight of the bill moved. Medium Voltage energy rates fell to roughly 29 to 31 sen/kWh, which sounds like good news until you notice that the capacity and network charges are now billed per kW of your peak demand. Consumption got cheaper. Peaks did not.

That last point is the whole story for most facilities. A plant that reduced its kWh but never touched its load profile will find less of its bill responds to the effort than it used to.

What are the new TNB tariff categories?

There are three non-domestic TNB tariff categories, split by supply voltage, and each one comes in a General or a Time-of-Use (ToU) version:

- Low Voltage: above 50 V up to 1 kV. Typical shoplots, small offices, light commercial premises.
- Medium Voltage: above 1 kV up to 50 kV. Most factories, malls, hospitals, hotels and office towers with their own substation.
- High Voltage: above 50 kV. Large industrial sites and heavy loads.

The structural difference that matters is between Low Voltage and everything above it. For Low Voltage non-domestic, capacity and network charges are levied per kWh, so there is no separate maximum demand charge to manage. At Medium and High Voltage, capacity and network are charged per kW of demand, which is where the numbers get large.

Rates for Low Voltage and High Voltage change with the schedule and are not worth quoting from memory. Pull them from the official myTNB tariff schedule or the TNB commercial and industrial pricing page before you build a business case on them.

Where does my old tariff letter map?

Use the table below as a starting point, then confirm against your actual bill. The mapping follows supply voltage and whether you were already on a time-differentiated tariff.

The mapping is a guide, not a guarantee. A site that took supply at 11 kV but was billed on a low voltage arrangement, or one that changed its connection agreement recently, can land somewhere the table does not predict.

The five components on your new bill

Every non-domestic bill under RP4 now carries five components, and they behave very differently.

Energy charge is sen per kWh, applied to everything you consume. This is the one most people still think of as "the tariff".

Capacity charge is per kW of your billed maximum demand at Medium and High Voltage, and per kWh at Low Voltage. It pays for the generation capacity held available for you.

Network charge works the same way, per kW or per kWh depending on category, and covers transmission and distribution.

Retail charge is a fixed amount per month for metering, billing and customer service. It does not move with your consumption.

AFA, the Automatic Fuel Adjustment, replaced ICPT. It is a monthly adjustment reflecting fuel and generation cost movements, and it can be a rebate or a surcharge.

Separately from the five components, the power factor surcharge survived the restructure. It applies when your power factor falls below 0.85 for supply below 132 kV, or below 0.90 at 132 kV and above. If you have never checked, it is worth doing: a capacitor bank that has quietly lost a stage will cost you every month until someone notices. Our walkthrough on how to read a TNB electricity bill shows where each of these lands on the printed page.

Worked example: Medium Voltage demand charges

At Medium Voltage, demand charges are billed on the single highest 30-minute interval of the month. Not the average, not the sustained load. One half hour sets the number.

The published rates are:

- Medium Voltage General: RM29.43 capacity + RM59.84 network = RM89.27 per kW per month
- Medium Voltage ToU: RM30.19 + RM66.87 = RM97.06 per kW per month

Take an illustrative factory on Medium Voltage that peaks at 850 kW at 11pm during a night shift startup, and separately hits 800 kW at 3pm on a weekday.

On General, all hours are equal, so the billed demand is the 850 kW night peak: 850 × RM89.27 = RM75,879.50 for the month.

On ToU, the peak window is 2:00pm to 10:00pm on weekdays. Demand recorded outside that window is not charged, so the 11pm spike is ignored and the billed demand is the 800 kW afternoon peak: 800 × RM97.06 = RM77,648.00.

In this case ToU is slightly worse on demand charges, because the higher ToU per-kW rate more than cancelled the 50 kW that the off-peak exemption removed. That is the trade-off in one paragraph, and it is why the decision has to be made on your own interval data rather than on a rule of thumb. ToU also applies different energy rates inside and outside the peak window, which pulls in the opposite direction if a meaningful share of your kWh runs at night or on weekends.

What is not ambiguous is the value of the kW itself. On General, every 50 kW you keep off the monthly peak is worth RM4,463.50 a month, or RM53,562 a year, and it recurs for as long as the peak stays down. You can run the arithmetic on your own numbers with our maximum demand calculator, and the mechanics of how that single interval gets set are covered in maximum demand charges under RP4.

How do I find my tariff category on my bill?

Look at the tariff or category field near the account details block at the top of the bill, then confirm it against the charge structure below.

The fastest check is the demand line. If you see a charge expressed in RM per kW, you are on Medium or High Voltage. If capacity and network appear in sen per kWh with no kW figure anywhere, you are on Low Voltage. To tell General from ToU, look for peak and off-peak kWh split into separate lines: General bills a single consumption figure, ToU splits it.

If the printed category still shows an old letter on a recent bill, treat it as a legacy label and ask TNB or your account manager to confirm the current one in writing before you model anything.

General or ToU: how should you decide?

Decide on interval data, not on the headline rate. The ToU window under RP4 is 2:00pm to 10:00pm on weekdays, with off-peak covering 10pm to 2pm on weekdays plus all weekends and selected public holidays.

ToU rewards two things: energy that genuinely runs outside the peak window, and a peak that occurs at night. It penalises a facility whose demand peak sits squarely in the afternoon, because you then pay the higher per-kW rate on the same kW you were already paying for. An office tower with a 3pm chiller peak and Monday-to-Friday occupancy is the classic case where switching looks attractive and is not. A cold store or a plant on a genuine night shift is the case where it usually is. We work through the decision in detail in should you switch to the TNB ToU tariff.

Whichever category you are on, the operational lever is the same under RP4: know which half hour is setting your demand, and know it while the month is still running rather than four weeks later on a PDF. That means interval visibility on the incomer, plus enough submetering to attribute the peak to a chiller, a compressor or a production line you can actually stagger.

CobiNeural gives that view as a live Max Demand KPI across energy, water, indoor air quality and chilled-water systems, either standalone or as an overlay on an existing BMS or SCADA, with alerts before the interval closes rather than after.

If you want a second pair of eyes on which category you are on and what your current load profile is really costing you, send us a recent bill and, if you have it, a month of interval data. We will map it to the RP4 structure and show you where the peak is being set. Request a demo and we can go through it together.