5.7 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Electricity meter | 8/9 | https://en.wikipedia.org/wiki/Electricity_meter | reference | science, encyclopedia | 2026-05-05T09:42:32.585250+00:00 | kb-cron |
== Tampering and security == Meters can be manipulated to make them under-register, effectively allowing power use without paying for it. Power companies often install remote-reporting meters specifically to enable remote detection of tampering, and specifically to discover energy theft. The change to smart power meters is useful to stop energy theft. When tampering is detected, the normal tactic, legal in most areas of the United States, is to switch the subscriber to a "tampering" tariff charged at the meter's maximum designed current. At US$0.095/kWh, a standard residential 50 A meter causes a legally collectible charge of about US$5,000.00 per month. Meter readers are trained to spot signs of tampering, and with crude mechanical meters, the maximum rate may be charged each billing period until the tamper is removed, or the service is disconnected. A common method of tampering on mechanical disk meters is to attach magnets to the outside of the meter. Strong magnets saturate the magnetic fields in the meter so that the motor portion of a mechanical meter does not operate. Lower power magnets can add to the drag resistance of the internal disk resistance magnets. Magnets can also saturate current transformers or power-supply transformers in electronic meters, though countermeasures are common. Some combinations of capacitive and inductive load can interact with the coils and mass of a rotor and cause reduced or reverse motion. All of these effects can be detected by the electric company, and many modern meters can detect or compensate for them. The owner of the meter normally secures the meter against tampering. Revenue meters' mechanisms and connections are sealed. Meters may also measure VAR-hours (the reflected load), neutral and DC currents (elevated by most electrical tampering), ambient magnetic fields, etc. Even simple mechanical meters can have mechanical flags that are dropped by magnetic tampering or large DC currents. Newer computerised meters usually have counter-measures against tampering. AMR (Automated Meter Reading) meters often have sensors that can report opening of the meter cover, magnetic anomalies, extra clock setting, glued buttons, inverted installation, reversed or switched phases etc. Some tampers bypass the meter, wholly or in part. Safe tampers of this type normally increase the neutral current at the meter. Most split-phase residential meters in the United States are unable to detect neutral currents. However, modern tamper-resistant meters can detect and bill it at standard rates. Disconnecting a meter's neutral connector is unsafe because shorts can then pass through people or equipment rather than a metallic ground to the generator or earth. A phantom loop connection via an earth ground is often much higher resistance than the metallic neutral connector. Even if an earth ground is safe, metering at the substation can alert the operator to tampering. Substations, inter-ties, and transformers normally have a high-accuracy meter for the area served. Power companies normally investigate discrepancies between the total billed and the total generated, in order to find and fix power distribution problems. These investigations are an effective method to discover tampering. Power thefts in the United States are often connected with indoor marijuana grow operations. Narcotics detectives associate abnormally high power usage with the lighting such operations require. Indoor marijuana growers aware of this are particularly motivated to steal electricity simply to conceal their usage of it.
== Global standards for Electricity Metering ==
Electricity meters are governed by various standards worldwide to ensure accuracy, reliability, and interoperability. These standards vary by region and are often based on national or international regulations. Below are the key standards used in different regions. European Standards
In Europe, electricity meters are primarily regulated under the Measuring Instruments Directive (MID), established by the European Union. MID ensures that electricity meters meet specific technical and operational criteria for accurate billing. Key standards include: EN 50470-1 to EN 50470-3: These standards specify general requirements, particular requirements, and tests for active energy meters. IEC 62052 and IEC 62053 series: Commonly applied for the functional and accuracy performance of electricity meters. American Standards
In the United States, the standards are developed by the American National Standards Institute (ANSI) and the Institute of Electrical and Electronics Engineers (IEEE). Key standards include: ANSI C12 Series: Covering meter accuracy, testing, and performance for residential, commercial, and industrial meters. IEEE 1708: Provides guidelines for testing the cybersecurity of smart meters. Chinese Standards
In China, electricity meter standards are governed by the China National Standards (GB), which align with international practices but also reflect specific local requirements: GB/T 17215: Sets the requirements for static electricity meters for active energy. DL/T 645: Specifies the communication protocol for multi-function electricity meters, ensuring interoperability. Australian Standards
In Australia, electricity meters adhere to the standards set by Standards Australia and the National Measurement Institute (NMI): AS 62052.11 and AS 62053.21: Align with IEC standards for general requirements and accuracy classes of electricity meters. NMI M 6: Specifies the metrological requirements for electricity meters used for billing.