Three-phase grid-tie solar
A shop or a small factory on a 3-phase 230/400 V service: a string inverter per phase (or a three-phase inverter, which the lab does not have yet), balanced across L1, L2, L3. A stub to grow.
Open it in the simulator ▸Size it from my electric bill
What is in it
6,750 W of panels, 7,500 W of inverter. 32 parts in all, wired and sized the way the lab's solar studio sizes them.
- Three strings of five 450 W, one per phase
Equal arrays per phase keep the service balanced; 253 V cold per string. - A grid-tie inverter per phase, 2.5 kW
Three single-phase units are the budget route; a three-phase inverter replaces all three (not in the lab yet). - A solar breaker per phase on its own pole
Each phase’s backfeed counts against that phase’s busbar (NEC 705.12). - DC and AC SPD per phase, ground rod
Each inverter protected on both sides. - What is missing
A three-phase meter, phase-balance monitoring, the busbar: grow it from here.
A clear day on this system
Open it in the simulator and press ⏱ Test run to watch a day on it.
Parts and prices
Philippine prices as estimates (about US$3,107 in all at ₱64 per US$). In the simulator, Buy all the parts gives the same list with shop links where we have them.
| Part | Qty | Est. |
|---|---|---|
| Grid-tie inverter String inverter 2500 W · MPPT 80–550 V | 3 | ₱67,500 |
| Solar panel 450 W · 144 half-cell mono | 15 | ₱121,500 |
| AC breaker 2-pole MCB · C16 | 3 | ₱840 |
| DC breaker 2-pole MCB · C16 | 3 | ₱1,140 |
| Surge protector (SPD) PV DC SPD, Type 2, 1000 V · DIN-rail module, two pluggable varistor cartridges with a status window each | 3 | ₱4,200 |
| MOV varistor 14D471K metal-oxide varistor · 470 V at 1 mA | 3 | ₱36 |
| 12 AWG (3.5 mm²) THHN any colour | 2 m | ₱96 |
| 12 AWG (3.5 mm²) THHN red | 2 m | ₱96 |
| 14 AWG (2.0 mm²) THHN any colour | 7 m | ₱245 |
| 14 AWG (2.0 mm²) THHN black | 1 m | ₱35 |
| 14 AWG (2.0 mm²) THHN red | 2 m | ₱70 |
| 8 AWG (8.0 mm²) THHN any colour | 9 m | ₱990 |
| 8 AWG (8.0 mm²) THHN red | 10 m | ₱1,100 |
| PV cable 4 mm² black | 9 m | ₱540 |
| PV cable 4 mm² red | 8 m | ₱480 |
| Estimated total | ₱198,868 |
What the safety check verifies
- ✓ Cold-morning Voc inside the L1 grid-tie inverter's input
- ✓ Hot-noon Vmp stays above the controller’s minimum
- ✓ PV conductors rated for 1.56 × Isc
- ✓ Array-to-controller voltage drop
- ✓ DC disconnect between array and controller
- ✓ Cold-morning Voc inside the L2 grid-tie inverter's input
- ✓ Cold-morning Voc inside the L3 grid-tie inverter's input
- ✓ L1 grid-tie inverter is grid-interactive (anti-islanding)
- ✓ L2 grid-tie inverter is grid-interactive (anti-islanding)
- ✓ L3 grid-tie inverter is grid-interactive (anti-islanding)
- ✓ Surge protection on each side
- ✓ Every SPD’s PE reaches the earth
- ✓ Grounding electrode present
Questions
How big is this three-phase grid-tie solar?
As drawn: 6,750 W of panels, 7,500 W of inverter. Every size can be changed in the simulator, and Solar & wiring → My house sizes one from your electric bill.
Does it work in a brownout?
No: like any grid-tie system it shuts down with the grid.
Is the wiring diagram correct?
It is drawn from the working simulation: every line is a real connection on the bench, and the safety check passes 21 checks with no fails. It is a design to learn from and adapt: check it against your local electrical code and the manuals of the parts you buy.
On the bench
Open it in the simulator ▸All solar systems and builds
Other systems
Off-grid solar system · Grid-tie solar system · Hybrid solar system · Off-grid inverter + ATS (budget hybrid) · AC-coupled solar with battery · 12 V solar for an RV, boat or small DIY