HT & LT metering cubicles
The instrument the bill is settled on. Build it before the licensee approves the scheme and you will build it twice.
Manufacturing · In short
An HT metering cubicle houses the current and voltage transformers and the energy meter at the boundary between a consumer or generator and the utility. It is the instrument on which every rupee of the energy bill is settled, so its accuracy class, ratios and sealing arrangement are fixed by the licensee’s approved metering scheme. Enersys Engineers manufactures 11 kV and 33 kV CT/PT metering cubicles and LT metering panels, and designed and built Odisha’s first 11 kV metering cubicle.
What is inside
- Current transformers of the approved ratio and metering accuracy class
- Voltage (potential) transformers with primary and secondary protection
- ABT-compliant special energy meter, and a check meter where the scheme requires one
- Test terminal block permitting meter testing without disconnecting the primary
- Sealing arrangement on every access point, to the licensee’s requirement
- Interlocked access and earthing provision for safe maintenance
- Communication port and modem for remote meter reading and despatch centre telemetry
Getting the scheme right first
The CT and PT ratios, the meter accuracy class, the physical arrangement and the sealing points are all specified by the distribution licensee or the transmission utility. None of them is a manufacturer’s choice.
This is why we hold manufacture until the metering scheme is confirmed in writing — and why we handle the DISCOM approval that confirms it. Ordering the cubicle before the scheme is approved is one of the most common and most avoidable causes of rework on an HT connection.
Where they are used
- Consumer interface metering on a new HT service connection
- Generator interface metering at the injection point
- Solar plant metering at the pooling substation or evacuation point
- Open access metering, where ABT compliance and telemetry are mandatory
- Check metering and joint metering points
- Internal energy accounting metering between plant sections
Testing and certification
- CT and PT ratio, polarity and burden verification
- Insulation resistance and high-voltage withstand test
- Meter accuracy verification and calibration certificate
- Secondary injection of the metering circuit
- Joint inspection and sealing with the licensee
Frequently asked
What accuracy class is required for HT metering?
It is set by the licensee and by the metering regulations applicable to the connection — interface and ABT metering requires a higher accuracy class than internal energy accounting. The approved metering scheme states it, which is why that approval precedes manufacture.
What is a test terminal block for?
It allows the meter to be tested, shorted or replaced without breaking the CT secondary circuit or disconnecting the primary. Opening a live CT secondary is dangerous, and the test terminal block is what prevents it.
Can you supply metering cubicles for open access consumers?
Yes — including ABT-compliant special energy meters and the communication link the load despatch centre requires for scheduling and energy accounting.
What usually goes with this
These are the adjacent scopes clients most often need alongside it.
DISCOM approval & connection
The distribution licensee decides your supply voltage, your metering arrangement and your connection date. Those are engineering questions before they are administrative ones.
Read more →ApprovalsSLDC, RLDC & NLDC registration and scheduling
Registration is a one-off. Scheduling and deviation settlement are for the life of the asset — and they carry real money.
Read more →ManufacturingElectrical & automation panel manufacturing
Built by the team that drew the protection scheme and ran the fault study — so the specified rating is the installed rating.
Read more →ManufacturingRelay & metering panels
The panel and the grading study come from the same team, so the settings that were calculated are the settings that get applied.
Read more →Need metering cubicles? Tell us the scope.
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