Introduction and overview

The Integrated Single Phase (ISP ECU) meter is a compact, two wire, keypad-based prepayment electricity meter with Earth Leakage Protection in a housing compatible with the ESKOM standard common base electricity dispensersocket.

This meter is most suited to new reticulation and is directly and easily interchangeable with common base prepayment meters from other approved manufacturers using the common base configuration.

User interaction with the meter and access to meter information (such as a low credit warning, energy consumption, and load contactor status) are available using the keypad and LCD display.

Principle of Operation

The ISP ECU meter is based on the ESKOM Specification,which calls for a prepayment meter that can be fitted into a standard, plug-in common base. This concept ensures simple installation and replacement procedures.

The meter is keypad based, fully STS compliant and supports the 20 digit STS encryption algorithms. The meter has a wide range of information registers which can easily be accessed by pressing the information button on the keypad and then entering the number of the register.

More detailed information and programming is achieved via the standard ESKOM VTC interrogation port at the rear of the meter

Integration of a supply isolator, earth leakage protection and overcurrent and short-circuit protection into the prepayment meter eliminates the need for a distribution board in the house, thereby reducing overall installation costs.

Features

• ESKOM standard housing compatible with ESKOM standard plug-in base
• Easy to install and ideal for new reticulation
• Proven Cashpower keypad technology
• Meter provides valuable information to help consumers effectively manage and budget their
  electricity consumption
• 30mA earth leakage current protection
• 20A and 60A overcurrent protection models available
• Programmable software power limit
• Fully STS compliant
• Language independent user interface
• ABS 1524 and IEC 61036 compliant
• Superior performance in the areas of:(1)
  • Operating Voltage Range
  • Accuracy Class
  • Metrological Performance
  • Earth Leakage Protection
  • Overvoltage Withstand
  • EMC Compatibility
  • Material Specification

(1) See detailed specifications for more information on improved performance.

Protection

The ECU is fitted with a 2-pole circuit breaker/isolator, which breaks both live and neutralpoles.

Apart from the meter’s programmable Power Limit functionality, it is also protected against overcurrent and short-circuit currents by means of a thermalmagnetic or hydraulic-magnetic trip mechanism in the live pole of the circuit breaker.

Electronic earth leakage detection protects against residual currents (earth leakage fault currents) by tripping the circuit breaker. This protection circuitry is independent of the metering circuitry for improved reliability and rapid response times. A dedicated earth leakage test key (T) is provided for consumers to regularly verify the integrity of the protection circuitry.

Tamper Resistance

The ECU electronic circuitry is mechanically sealed at the time of manufacture by screw sealing plugs. These plugs will be destroyed if attempts are made to access the screws.

On installation, the ECU is secured to its socket base with two screws. These screws are then covered with
a plastic plug and finally sealed with a cable and crimp ferrule clearly visible from the front of the meter. This ensures that there are visible signs of tampering if unauthorised entry to the system is attempted.

Plug-in base

The plug-in-base, which also conforms to ESKOM’s specifications, allows the commissioning of the meter to be separated from the installation of the wiring, thereby adding flexibility and installation convenience.

Included with the base is a Metal Oxide Varistor (MOV), which ensures that the meter complies with SANS IEC 61643-1 for class 3 arrestors. The base is optional and can be supplied separately to the meter.