Field log · Meralco net metering · Cavite, PH

Net Metering Journey in General Trias

What it actually took to get a 6 kWp rooftop array approved for net metering with Meralco — documents, venues, fees, and dates, with no hype.

Published 16 May 2026

Why bother with net metering

I have a roughly 6 kWp rooftop solar array in Cavite. "6 kWp" just means the panels can push about 6 kilowatts at full sun — enough, on a bright day, to run the house and spill the surplus somewhere. Without net metering that surplus is wasted: it either trips the inverter or back-feeds for free. With net metering, Meralco swaps your meter for a bi-directional one and credits the energy you export against the energy you import. The system isn't generous (you're credited at the blended generation rate, not the retail rate), but it turns wasted midday production into something that shaves the bill. The catch is the paperwork. Here is exactly how mine went, dates and fees included, so you can budget your patience.

Verified as of January 2026. This is a single filing in Rosario, Cavite (Dec 2025 – Jan 2026). Meralco's forms, fees, and venues — and the LGU permit costs — change without notice and vary by district. Treat the specifics below as a worked example, not a current price list, and confirm the latest requirements with your Meralco business center before filing.

Who net metering is for

Net metering pays you back only for energy you export — the surplus your panels make while the house isn't using it. That shapes who actually benefits:

• Daytime exporters. If the house is empty from morning to late afternoon — nobody home, no aircon, no midday EV charging — production has nowhere to go but the grid. Net metering captures it. This is the strong case.
• Oversized arrays. A 6 kWp array on a house drawing 1–2 kW at noon spills most of what it makes. Net metering turns that spill into credit instead of waste.
• Poor fit: a small array sized tightly to a load that runs all day, or a household that already self-consumes nearly everything. The credit is small and the up-front fees (itemized in What "net-meter ready" actually costs, below) may outweigh it.

One point worth internalizing: the export credit is at the blended generation rate, not the retail rate. You are not selling power back at what you pay for it. Every kWh you consume on-site is worth more than the same kWh exported. Net metering recovers otherwise-wasted surplus; it is not a revenue stream.

Once you accept that self-consumed energy beats exported energy, the battery question follows:

• No battery (grid-tied + net metering). Cheapest. All surplus exports for credit; you still buy from the grid at night at retail and offset it with credits earned at the lower generation rate. Lowest capex, nothing to replace in 8–10 years.
• A modest battery. Shifts the day's surplus into the evening instead of exporting it cheap and re-importing it dear. The win is the retail-minus-generation spread you stop losing, plus outage ride-through.
• More battery (discharge-bound). Each added kWh is discharged fewer days per year — it earns its keep only in long cloudy stretches or long outages. Past one evening's load, extra capacity is insurance, not savings.
• More battery than your surplus can fill (charge-bound). A battery only pays back on energy that actually cycles through it. If your midday surplus — production minus whatever the house is drawing at that moment — is modest, a larger battery never fully charges: it sits at partial state of charge day after day, the extra kWh never cycle, and that capacity returns nothing while still aging on the calendar. This is the stricter limit, and the one people miss: sizing past your evening load buys a battery that is at least full and idle; sizing past your daily chargeable surplus buys one that is never even full. Pull your real daily export figures from the inverter logs before upsizing — if you are exporting only a few kWh on a good day, a bigger battery cannot be charged to use them.

Honest framing for a net-metered house: net metering is the cheap backstop for surplus you can't store; a useful battery is bounded by the smaller of one evening's essential load and the surplus a typical day can actually charge into it; beyond that you are buying resilience, not return.

Net metering approves an install that already exists, so some cost lands on the install, not the filing:

• The installer's net-meter-ready surcharge. This is the cost most people miss. A standard grid-tie install does not include the continuous rigid metal conduit (RMC) run from the service entrance to the inverter — and that run is the one thing the Meralco site inspector actually scrutinizes (the inspection is narrower than the SLD suggests: they verify the RMC runs continuously with correctly spaced clamps and supports, and don't really audit AC-disconnect labeling, SPDs, or 24-hour PV access — those still belong in the build for code and safety). Making the setup net-meter ready means the installer bills extra for: the RMC itself, the additional cable to run inside it, the clamps and supports at code spacing, and the labor — bending 1-inch rigid pipe to follow the wall and corners cleanly is slow, skilled work, not a quick add. Get this scoped and priced in the original contract; specifying it up front is far cheaper than discovering at the Dec 18 inspection that it has to be torn out and redone.
• The PEE-sealed A3 SLD — PHP 3,500 in my case, entirely outside the install.
• Government/meter fees — about PHP 3,700 (City Hall cert + wiring permit
  • the bi-directional meter cost difference).
• Access to the service-entrance post. Meralco's crew has to physically reach the service entrance to swap in the bi-directional meter (and, historically, to mount a REC meter beside it). If the post is boxed in, behind a locked gate, or hard to reach with a bucket truck, that becomes your problem on meter-swap day. Confirm it is accessible before you file — it is the one prerequisite with nothing to do with paperwork, and the easiest to forget. Worse case: a shared post. In townhouse and tight-lot subdivisions the service entrance is often a single shared post feeding several units — possibly out front and a few doors down, not on your own frontage. Net metering needs the bi-directional meter on your service, which can mean building a dedicated post for your unit and securing the developer's written approval to erect it. That is a separate, slow, developer-gated project on top of everything else here — realistically not worth the hassle, and worth checking your village's setup before you commit to net metering at all.

Prep work before filing

Before anything else, make your installation net-meter ready. Net metering approves an install that already exists — Meralco won't wait while you fix things, and the RMC conduit run is exactly what the site inspection turns on (detail and what it costs: What "net-meter ready" actually costs, above). Confirm with your solar installer up front that the build will pass.

One tip before you spend a peso: when shopping for a Professional Electrical Engineer (PEE), ask to see a sample A3 Single Line Diagram (SLD) covering the twelve blocks below. If their sample has all of them, they'll likely produce a utility-ready drawing on the first pass. If it doesn't, you'll be paying for revisions and losing weeks.

The single most important document is the A3 SLD sealed by a PEE. You do not draw this yourself. PEEs who do solar net-metering drawings are easy to find — the Facebook solar groups are full of them, and most quote a flat fee. I paid PHP 3,500 for mine, turned around in a few days once I sent the inputs.

The inputs your PEE will ask for:

• The building blueprint, specifically the page with the schedule of loads for your existing house panel.
• The solar panel datasheet (the PDF from the manufacturer).
• The inverter datasheet.
• A Google Maps pin of the exact service address — the one tied to your Meralco account.

It's worth knowing what you're paying the PEE to produce, and why Meralco insists on each piece. Generically, a utility-ready A3 SLD carries twelve blocks:

1. The Single Line Diagram proper — the main schematic showing power flowing from the utility service entrance, through the bi-directional meter, into your main panel, with the PV strings feeding the inverter and tying back through a dedicated AC breaker. It also shows the disconnect switches, surge protection devices (SPDs), the CT sensor for the bi-directional meter, and, for hybrid systems, the battery branching off the inverter through its own DC breaker. This is the drawing the utility reads first; everything else justifies the numbers on it.

2. Solar panel datasheet block — module model, Pmax, Imp, Vmp, Isc, Voc. These set the DC-side electrical envelope everything else is sized against.

3. Inverter datasheet block — model, DC input limits, MPPT voltage range, number of MPPTs and strings, AC output rating, grid voltage and frequency range, power factor, THDi, and efficiency. This proves the inverter can legally and safely synchronize with Meralco's grid.

4. Electrical Notes — the generic Philippine Electrical Code (PEC) compliance boilerplate. Boring, but its absence is a rejection.

5. Solar Electrical Notes — the solar-specific rules: 24-hour utility access to the PV equipment, UL 1703 modules, sunlight- and wet-rated conductors, REC meter placement near the bi-directional meter, tapping rules, rigid/IMC conduit on the line side, and a warning label at the disconnect. These are the clauses the inspector physically checks against.

6. Design Analysis — the math that sizes your breakers, wires, and conduit: Isc × 1.25 for the DC breaker and SPD, a per-string voltage-drop check, and the AC-side Pmax / Vac that sizes the inverter breaker. Hybrid setups add a battery-protection calc that sizes the battery DC breaker and cable. This is what makes the picture in block 1 defensible.

7. Site Location — a small map clip with a pin on the service address, so the inspector finds the right house.

8. Schedule of Loads — an inventory of your existing house panel: circuit list, VA load, amps, breaker AT/AF, wire and conduit per circuit, and the totals that drive your main breaker and feeder size. The utility needs to know solar isn't being bolted onto an undersized service.

9. Short Circuit calculation — fault-current analysis starting from the utility transformer's KVA, voltage, and %Z, used to set the required KAIC interrupting rating of your main breaker, so the breaker can actually clear a fault instead of welding shut.

10. Voltage Drop calculation — the feeder-level VD = (2 × L × R × I) / 1000, confirming %VD stays inside code.

11. Service Entrance detail — an elevation view showing meter height (around 5 ft), the bi-directional meter, taps to the service equipment, the run to the inverter, and the ground rod. This is what the field crew builds to.

12. Title block — PEE name, PRC registration number, PTR number, date and place issued, project title, owner, location, sheet contents, sheet number, and the PEE dry seal. The seal plus the PTR and PRC ID is precisely what makes the SLD acceptable to Meralco. A perfect drawing without the seal is wallpaper.

Required documents at a glance

The trap in the requirements list is that it reads flat, but it isn't. Most items are not separate filings — they are attachments rolled into a parent submission, and a few core artifacts (above all the PEE-sealed A3 SLD) recur across several steps. Prepare them as bundles, and photocopy the recurring ones in quantity.

1. Meralco net-metering application — the bundle handed over at filing (Dec 9):

2. City Hall — Certificate of Electrical Inspection + Wiring Permit (the CFEI, Dec 19). Gated by the yellow card, which Meralco issues only after the site inspection — you cannot file this earlier:

3. Contract signing — Meralco (Jan 9):

★ The recurring ones — items marked ★ are consumed at more than one step, so photocopy them in quantity before you start. The PEE-sealed A3 SLD recurs most (application bundle, site inspection, and City Hall); the TCT / Contract to Sell photocopy is needed at City Hall and at contract signing.

The timeline, step by step

Dec 9, 2025 — Application at Meralco Rosario Cavite. The Meralco Rosario business center is on the 2nd floor of SM City Rosario (map pin). Bring the full bundle from the Required documents at a glance table above (blank PDF forms are linked there) — and above all your latest Meralco bill, which ties the application to the account and service address; forgetting it stalls you on day one. What to expect: the counter staff check completeness, not correctness, then you wait for the impact study and an inspection schedule. You're assigned a Meralco engineer who becomes your point person — get their Viber number here, because nearly every later step is coordinated through them. Have the forms filled before you arrive; there is no comfortable place to do it there.

Dec 18, 2025 — Site inspection. A Meralco-side check at the house, focused narrowly on the RMC run (what they scrutinize and why is covered above). What to expect: quick if the conduit run is clean. Be there and keep the SLD handy. This is where you find out whether your installer did the conduit work properly — and there is not much you can do at this point but hope they did.

Dec 19, 2025 — Yellow card issued. The next day I picked up the "yellow card" at Meralco Rosario. What to expect: this card is the key that unlocks the City Hall step — don't file at City Hall before you have it.

Dec 19, 2025 — City Hall, same day. Straight to the General Trias City Hall (map pin), City Engineer's Office, for the Certification of Electrical Inspection (PHP 1,254) and the Wiring Permit (PHP 165), with the bundle from table 2 (the yellow card is the gate item — you can't file here without it). What to expect: a separate office from Meralco with its own queue and cashier. I snapped the official receipts and forwarded them to the Meralco engineer over Viber — that photo is what moved my file forward, so get the engineer's Viber early.

Jan 9, 2026 — Contract signing at Meralco Rosario. The three documents in table 3 are signed here (the Fixed Asset Boundary Document names your system — mine: 6.000 kWp to Meralco's secondary distribution, TLN # ‹redacted›). I paid PHP 2,312.77, the bi-directional meter's cost difference. What to expect: a notary is involved — budget time, and bring spare TCT/Contract-to- Sell photocopies; it's consumed here as well as at City Hall, and running out means another trip.

Note the recurring "no REC meter" language. I opted out, which is why the agreement is the amended version and why there is a separate notarized Affidavit and Waiver on REC Metering. Whether you should do the same is its own decision — see Should you waive the REC meter?, below.

Jan 28, 2026 — Meter swap. A crew came to the service address and installed the bi-directional meter. What to expect: a brief power interruption, then you're officially exporting.

Should you waive the REC meter?

The REC meter is not for your bill. Your net-metering credit is a peso amount from net energy exported, read off the bi-directional meter (Sec. 4(s), Sec. 13) — identical whether or not a REC meter exists. The REC meter measures gross generation, including what the house consumes on the spot (Sec. 4(dd)). Under ERC Resolution No. 15, Series of 2025 — the 2025 Amended Net-Metering Rules — that gross figure serves exactly two purposes (Sec. 10), neither being your monthly bill:

• The utility's RPS compliance. The DU computes RECs from your gross generation toward its Renewable Portfolio Standards obligation. A REC is issued to "Mandated Participants of the RPS" (Sec. 4(cc)) — the utility and suppliers, not you; a residential customer cannot personally trade RECs, meter or no meter.
• Subsidy classification. Gross generation derives your "actual energy consumption" — import plus own-use (Sec. 14) — for non-exemption from the lifeline and senior-citizen subsidy rates (Sec. 10(a)–(c), Sec. 15). Moot unless your actual consumption sits near the DU's lifeline threshold.

The meter is optional: the ERC publishes two NMA templates — Annex A-2.1 with and Annex A-2.2 without the REC meter — plus an Affidavit and Waiver (Annex 4). Take the no-REC-meter agreement and the notarized waiver and gross generation is estimated by the Sec. 19 formula instead — for rooftop solar, a flat installed kWp × 18.05% capacity factor × 0.7519 DC/AC ratio × monthly operating hours, a nameplate figure, not your real production. (Res. No. 15 was deliberated 13 August 2025, effective 15 days after publication; Meralco adopted it via a 22 September 2025 advisory.)

Why it collapses to "just waive it." On cost (Sec. 10) the DU shoulders the bi-directional meter except the end-user pays the difference over the old meter (the PHP 2,312.77 above); for the REC meter the DU shoulders the device and its installation but the QE bears the wiring from the facility to it. Waiving deletes exactly that QE-paid wiring run and a commissioning step. All you give up is a utility-side gross-generation record — moot for any house above the lifeline tier (a very low threshold, tens of kWh/month, far below any house running a multi-kWp array), where formula-vs-meter changes nothing about your rate; the RPS benefit was never yours, and your inverter's own telemetry (SolisCloud here) still records production. So for a typical above-lifeline customer it is pure upside — which is why my contract is the amended, no-REC-meter agreement (Annex A-2.2) with the notarized affidavit (Annex 4). The "keep the meter" exception is essentially academic: a household consuming little enough to sit at the lifeline tier would not be installing a multi-kWp array — let alone bearing net-metering's added fees — in the first place.

Total elapsed time

From application (Dec 9, 2025) to bi-directional meter (Jan 28, 2026): about 50 days, straddling the Christmas and New Year slowdown. Plan for roughly seven weeks and treat anything faster as a gift.

Closing

None of this is hard, exactly — it's just sequential, and each step gates the next. Do the prep right and roughly fifty days is a reasonable expectation. Then the meter spins backward on sunny afternoons, and the paperwork stops mattering.

For what that meter actually does to the bill over five months, see Residential solar performance. And if your roof is in Lancaster New City, the developer-side approval that comes before any of this is covered in the Solar Panel Installation Application Guide for Lancaster New City.

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