1. What Are They? (Definitions)
PT cabinet = a cabinet housing voltage transformers, stepping high voltage (6/10kV) down to 100V for measurement and protection;Metering cabinet = a cabinet housing electricity meters, measuring power consumption. One transforms voltage, the other records energy.
2. The 5 Core Differences (Comparison Table)
| Dimension | PT cabinet | Metering cabinet |
|---|---|---|
| Function | Transforms voltage for measurement/protection | Measures power consumption |
| Core components | Voltage transformer PT | Current transformer TA + electricity meter PJ |
| Location | Inside high-voltage switchgear | Dedicated low-voltage or high-voltage metering |
| Application | Voltage measurement/protection sampling | Basis for electricity billing |
| Accuracy | Class 0.5 | Class 0.2S/0.5S (metering class) |
3. What a PT Cabinet Does (3 Functions)
- Voltage measurement: steps 6/10kV down to 100V for the voltmeter
- Protection sampling: supplies signals to overvoltage/undervoltage protection
- Insulation monitoring: checks the insulation condition of the system
4. What the metering cabinet does (billing)
The metering cabinet isthe legal basis for electricity billing, fitted with a 0.2S class current transformer + 0.2S class kWh meter, sealed by the utility, and must not be tampered with by the user.
5. When do you need a PT cabinet? (high-voltage systems)
High-voltage 6/10kV systems always require a PT cabinet (voltage measurement and protection need it); low-voltage 380V systems do not need a PT (380V is measured directly) — only a metering cabinet.
FAQ FAQ
Can a PT cabinet and a metering cabinet be combined?
In high-voltage systems they are generally separate (PT inside the switchgear, metering in its own cabinet); in low-voltage systems they can be combined into a JP cabinet.
Do low-voltage systems need a PT cabinet?
No. 380V is measured directly; a PT is for stepping high voltage down.
Why is the meter in a metering cabinet sealed?
It is the basis for billing; the utility seals it to prevent meter tampering and electricity theft, and it must not be touched.
What is affected if a PT cabinet fails?
Voltage measurement and protection stop working, overvoltage/undervoltage protection does not trip, and immediate servicing is required.
Related pages:Technical notes · Products · Industries · Resource center · FAQ · Get a quote