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Configure solarYour TNB Phase Determines Your Solar Size.
Do You Know Yours?
Most homeowners don't know if they're on single phase or three phase — until a solar installer tells them they can't get the system they wanted. This guide fixes that. Check your phase in 2 minutes and know exactly what solar system you can install.
Single phase (2 wires) = max 5kWac solar. Ideal for bills RM200–RM350/mo.
Three phase (4 wires) = max 15kWac solar. Ideal for bills RM300–RM1,000+/mo.
Bill >RM400 but single phase? You may need to upgrade first (TNB and your contractor quote this).
Single Phase vs Three Phase: The Simple Explanation
Malaysia's electricity grid distributes power through a three-phase system. Think of it as three separate streams of electricity, offset from each other. Your TNB connection taps into this grid — either drawing from one stream (single phase) or all three (three phase).
For solar, this matters enormously: TNB's Solar ATAP programme caps the system size based on your phase. A single phase home is limited to 5kWac. A three phase home can go up to 15kWac — 3x more power.
Single Phase
| Voltage | 230V |
| Wires | 2 wires |
| Max Current | 60A (13.8kW) |
| Max Solar | 5kWac |
Terrace houses, apartments, small semi-Ds
Three Phase
| Voltage | 400V (line-to-line) |
| Wires | 4 wires |
| Max Current | 60A per phase |
| Max Solar | 15kWac |
Large semi-Ds, bungalows, commercial
Why Most Terrace Houses Are Single Phase
When TNB wired Malaysian terrace houses in the 1970s–2000s, typical household loads were low (ceiling fans, small TVs, basic lighting). Single phase 230V at 60A was more than enough. Today, with 3+ ACs, water heaters, and EVs, many homeowners are hitting the limits — and solar makes this constraint more visible.
How to Check Your Phase: 4 Easy Methods
You don't need an electrician to figure this out. Pick the easiest method for you.
Method 1: Look at Your TNB Meter
Method 2: Count Wires at Your Main Distribution Board
Method 3: Check Your TNB Bill
Method 4: Call TNB Helpline
Quick Phase Check: Answer 3 Questions
Not sure? Answer these 3 quick questions:
How many ACs do you have?
What is your average monthly TNB bill?
What type of house?
Solar System Limits by Phase: What You Can Install
TNB's Solar ATAP programme sets limits based on your electrical phase. Going above them needs a TNB Connection Confirmation Check (CCC).
| System | System Size | Panel Capacity | Suitable Bill Range | Est. Monthly Savings |
|---|---|---|---|---|
Single Phase | 5kWac (7.44kWp) | 9–12 panels | RM200–RM350/mo | RM140–RM230/mo |
Three Phase | 15kWac (19.84kWp) | 13–32 panels | RM300–RM1,000+/mo | RM280–RM960/mo |
Important: The 5kW Cap Catches People Off Guard
Many homeowners see friends with 10kW+ solar systems and assume they can get the same. Then they discover they're on single phase and are limited to 5kW. The 5kW limit is a TNB grid stability requirement, not an installer limitation — it applies uniformly across all single phase connections in Malaysia.
When Should You Upgrade from Single to Three Phase?
Not everyone needs to upgrade. Use this decision guide to find out if it makes sense for you.
- Monthly bill consistently above RM400
- Planning to install an EV charger
- Have 3 or more air conditioners
- Want a solar system larger than 5kW
- Running a home office with heavy equipment
- Monthly bill below RM350
- No plans for EV charger
- Currently have 1–2 ACs
- Tight budget, want fastest payback
- A 5kW solar system will solve your energy needs
Upgrade Cost Items (2026)
Tip: If you're upgrading for solar, plan the upgrade together with the solar installation so the TNB application and the work are sequenced once. Get a written quote for the upgrade before you decide.
Inverter Options by Phase: What to Install
Single phase and three phase systems use different inverter models. These are not interchangeable. Here are options available in Malaysia for 2026.
1Single Phase Inverters (max 5kWac)
| Model | Capacity | Price (MYR) | Warranty | Efficiency | Best For |
|---|---|---|---|---|---|
| Sungrow SG3.0RS-ADA | 3kW | RM 1,800–2,200 | 10 yr | 98.4% | Sungrow premium option (catalogue upgrade) |
| Sungrow SG4.0RS | 4kW | RM 2,000–2,500 | 10 yr | 98.4% | Maximum single-phase output |
| Huawei SUN2000-4KTL-L1 | 4kW | RM 2,200–2,800 | 10 yr | 98.6% | FusionSolar app, smart optimizer |
| Solis S6-GR1P3K | 3kW | RM 1,600–2,000 | 10 yr | 97.7% | Same Solis S6 family as the catalogue base inverter (S6-GR1P5K) |
Trexon catalogue: Solis S6-GR1P5K is the single-phase base inverter in the Trexon catalogue; Huawei is +RM3,000 and Sungrow +RM5,000. Prices in this table are market estimates, and SKUs other than the catalogue models are not stocked by Trexon.
3Three Phase Inverters (up to 15kWac)
| Model | Capacity | Price (MYR) | Warranty | Efficiency | Best For |
|---|---|---|---|---|---|
| Huawei SUN2000-10KTL-M1 | 10kW | RM 5,500–7,000 | 10 yr | 98.6% | Best monitoring + smart optimizer |
| Sungrow SG10RT | 10kW | RM 4,800–6,000 | 10 yr | 98.4% | Best value 3-phase |
| Solis S5-GR3P10KTrexon catalogue | 10kW | RM 4,200–5,500 | 10 yr | 98.0% | Trexon catalogue base inverter |
| GoodWe GW10KT | 10kW | RM 4,500–5,800 | 10 yr | 98.3% | Not stocked by Trexon (market reference) |
Trexon catalogue: Solis S5-GR3P10K is the three-phase base inverter in the Trexon catalogue; Huawei is +RM3,000 and Sungrow +RM5,000. Huawei SUN2000 offers detailed FusionSolar monitoring for high-bill homes that want granular data. Prices are market estimates; SKUs other than the catalogue models are not stocked by Trexon.
The inverters we install comply with the applicable SIRIM/ST requirements for Malaysian residential use (2026).
Want a deep-dive on inverter types? Read our String Inverter vs Micro Inverter Malaysia 2026 guide.
Cost & ROI: Side-by-Side Comparison
Real 2026 pricing from Trexon installations in Klang Valley. Includes panels, inverter, mounting, wiring, permits, and monitoring app.
| System | Total Cost | Monthly Savings | Annual Savings | Payback Period | CO2 Saved/yr |
|---|---|---|---|---|---|
| 7.44kWp Single Phase | RM 17,999–22,999 | RM 230 | RM 2,760 | 6.5–8.3 years | 6.9 tonnes |
| 7.44kWp + Phase Upgrade | System price + upgrade quote | RM 230 | RM 2,760 | Depends on upgrade quote | 6.9 tonnes |
| 9.92kWp Three Phase | RM 23,999–28,999 | RM 370 | RM 4,440 | 5.4–6.5 years | 9.2 tonnes |
| 9.92kWp + Phase Upgrade | System price + upgrade quote | RM 370 | RM 4,440 | Depends on upgrade quote | 9.2 tonnes |
Estimate on the RP4 domestic tariff (from 1 Jul 2025), before AFA, the 1.6% RE Fund and service tax; Trexon catalogue prices (Solis to Sungrow; payback uses Solis); 3.5 sun-hours a day; about 40% of solar used at home and the rest exported and credited at the 27.03 sen Energy Charge (capped at what you import) for 10 years under Solar ATAP; no tariff increases. Single phase: 7.44 kWp on a RM350–RM600 bill. Three phase: 9.92 kWp on a RM500–RM600 bill. Phase-upgrade cost is quoted separately by TNB and your contractor and is not included in these figures. Your bill and roof will change the figures.
If you need to upgrade from single to three phase before installing a 9.92 kWp system, add the upgrade cost (quoted separately by TNB and your contractor) to the three phase system cost. Payback lengthens by that amount.
Frequently Asked Questions
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