- A bidirectional (net) meter records both import and export — every net-metering job needs one.
- A solar check meter is a second meter that records total generation as a cross-check.
- The check meter is often required above a capacity threshold set by the SERC — verify the figure.
- The net meter is DISCOM-supplied, tested and sealed — an EPC does not fit its own.
- An old import-only meter cannot be used — it is replaced at commissioning.
Net metering only works because of one device: a meter that counts power going both ways. Get the metering wrong and the whole job stalls at commissioning. This guide explains the bidirectional net meter and the solar check meter — what each does, when each is needed, and who installs and seals them, so your field crew gets it right the first time.
What a bidirectional meter is
A bidirectional meter, also called a net meter, records both the units a home imports from the grid and the units the solar system exports to the grid. Net metering nets the two, and the consumer pays only for the net import. The bidirectional meter replaces the old import-only meter at the service point.
This is the core idea of net metering. When the panels make more than the home uses, the extra flows to the grid and the meter counts it as export. When the home uses more than the panels make, the grid supplies it and the meter counts it as import. One device, two counts. The net-metered bill then settles the difference.
What a solar check meter is
A solar check meter is a second meter that records the total solar generation of the system as an independent cross-check. It sits between the inverter and the connection point, before the net meter. Its job is not billing — it confirms how much the plant actually generated, which helps the DISCOM verify the system and catch metering errors.
Why a second meter exists
The net meter only sees what crosses the boundary to the grid. It cannot tell how much the plant made in total, because the home consumes some solar on the spot. The check meter fills that gap by counting generation at the source. For larger systems, the DISCOM wants both numbers, which is why a check meter is common above a size threshold.
The two meters compared
Here is how the net meter, the solar check meter and the old single meter differ — what each measures, when it is needed, and where it sits in the circuit.
Comparison of net-metering meters. The check-meter threshold is set by the state SERC and changes with each amendment — verify the current figure with your DISCOM.
When a solar check meter is mandatory
A solar check meter is mandatory in many states once the system size crosses a capacity threshold set by the SERC, often used for larger commercial systems. Below that size, the net meter alone is usually enough. Above it, the DISCOM wants the independent generation count.
Verify the threshold before you quote
The check-meter threshold and the rule vary by state and change with each amendment. Do not quote from memory. Verify the current figure with your DISCOM and the SERC regulation before you finalise the design and the price, because an extra meter and its wiring add cost the customer should know about up front. For Delhi DISCOMs and other states, the threshold is set locally.
Who supplies and seals the meter
The DISCOM supplies the net meter, and it is tested and sealed by the DISCOM, not by the EPC. An EPC who buys and fits its own net meter will see it rejected at commissioning. The meter has to be a DISCOM-approved unit, tested for accuracy and sealed so it cannot be tampered with.
What the EPC does instead
Your job is to prepare a clean, code-compliant connection so the DISCOM meter drops in without fuss. You provide the single-line diagram, the earthing, the isolators and the meter board, and you may fit the solar check meter where the rule requires it. The bidirectional meter itself stays with the DISCOM. Meter cost and any security deposit are set by the DISCOM — verify the current figure.
Install, test and seal
The meter goes in near the end of the job, at the testing-and-sealing step that leads to commissioning. The sequence is fixed and an EPC cannot shortcut it.
- Connection ready — the EPC completes the wiring, earthing and isolators to standard.
- Old meter removed — the import-only meter comes off; it cannot stay for net metering.
- DISCOM net meter fitted — the DISCOM supplies and installs the bidirectional meter.
- Tested for accuracy — the DISCOM tests the meter so the import and export counts are trusted.
- Sealed — the DISCOM seals the meter against tampering, then commissions the system.
The whole step is covered in the testing, sealing and commissioning guide. If the DISCOM net meter is slow to arrive, the job sits idle — see net meter not installed for how to push it.
How to read a net meter
A net meter shows separate readings for import and export, so you read two numbers, not one. Most digital net meters cycle through the readings on the display, labelled for import and export in kWh. The bill then nets the export against the import for the period.
Import, export and net
Import is what the home drew from the grid. Export is what the solar sent to the grid. The net is import minus the export credit, and that is what the consumer pays for. Where a check meter is fitted, the generation number on it should be higher than the export number, because the home uses some solar on the spot. A check-meter reading lower than export is a red flag worth raising with the DISCOM.
Common metering mistakes
Metering mistakes are expensive because they surface at commissioning, after the install is done. Avoid these.
- Fitting your own net meter — the net meter must be DISCOM-supplied and sealed, so don't buy one.
- Skipping the check meter — above the SERC threshold, a missing check meter fails the inspection.
- Leaving the old meter — an import-only meter that spins backward is not allowed and must be replaced.
- Wrong meter location — the check meter sits before the net meter; placing it wrong skews the cross-check.
- Quoting without the deposit — meter cost and security deposit vary by DISCOM; confirm and include them.
Treat the meter as a DISCOM deliverable you schedule and chase, not a part you stock. The crew builds the connection; the DISCOM brings the sealed meter. Lining those two up on the calendar is what keeps commissioning on time.
How SuryaHub helps you track meters and parts
The meter is the step that quietly stalls jobs — a sealed DISCOM meter pending while the install sits done. SuryaHub tracks the meter status of every job, holds the meter and inverter details with the rest of the procurement and inventory record, and runs the net-metering and commissioning steps so a pending meter is flagged, not forgotten. SuryaHub is pre-revenue; the only real pilots are Suryantra Energy and RGESPL, and the figures here are scheme facts, not guarantees.
Never lose a job to a pending meter
See how SuryaHub tracks meters, parts and the commissioning step.
Related guides
Frequently asked questions
What is a bidirectional meter in net metering?+
A bidirectional meter, also called a net meter, records both the units a home imports from the grid and the units the solar system exports to the grid. Net metering nets the two and the consumer pays only for the net import. The bidirectional meter replaces the old import-only meter at the service point.
What is a solar check meter?+
A solar check meter is a second meter that records the total solar generation of the system as an independent cross-check. It sits between the inverter and the connection point, before the net meter. A solar check meter is often required above a capacity threshold set by the SERC, so verify the current rule with your DISCOM.
When is a solar check meter mandatory?+
A solar check meter is mandatory in many states once the system size crosses a capacity threshold set by the SERC, often used for larger commercial systems. The threshold and the rule vary by state and change with each amendment, so verify the current figure with your DISCOM and the SERC regulation before you quote.
Who supplies and installs the net meter?+
The DISCOM supplies the net meter, and it is tested and sealed by the DISCOM, not by the EPC. The EPC prepares the connection and may install a solar check meter where required, but the bidirectional net meter itself is DISCOM-supplied and sealed at commissioning. Costs and deposits are set by the DISCOM.
Can an old meter run backward for net metering?+
No, an old single meter that runs backward on export cannot be used for net metering. Net metering needs a bidirectional meter that records import and export separately. The old import-only meter is removed at commissioning and replaced with the DISCOM-supplied net meter, which the DISCOM tests and seals.
How does SuryaHub help track meters?+
SuryaHub tracks the meter status of every job, holds the meter and inverter details, and flags when a DISCOM net meter is pending so commissioning is not blocked. SuryaHub is pre-revenue; the only real pilots are Suryantra Energy and RGESPL, and figures here are scheme facts, not guarantees.
Sources & references
The metering definitions, standards and supply-and-seal process below come from primary government and DISCOM sources. Meter rules, thresholds, costs and deposits change by state and with each amendment, so confirm the current figure with your DISCOM.
- Central Electricity Authority (CEA) ↗
Metering regulations and the technical standards for energy meters.
- Ministry of Power ↗
Electricity (Rights of Consumers) Rules 2020 and the net-metering framework.
- BSES (Delhi DISCOM) ↗
A DISCOM example for meter supply, testing and sealing — verify your own DISCOM rule.
Written by the SuryaHub team · reviewed against CEA, MoP & DISCOM sources · updated 19 June 2026.
Method: Meter definitions and the supply-and-seal process are taken from the government and DISCOM sources above and re-checked every 30 days. Check-meter thresholds, meter costs and security deposits are state-specific estimates — verify the current figure with your DISCOM or the SERC. SuryaHub is pre-revenue; only Suryantra Energy and RGESPL are real pilots.
Change log: 19 Jun 2026 — first published.