Introduction and overview
The Split Single Phase (SSP) meter is a
compact, two wire, keypad-based prepayment electricity meter
which comprises two parts, the Energy Management Unit (EMU)
and the Customer Interface Unit (CIU).
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 on the CIU
Split Meter Concept
The meter consists of two parts namely,
the CIU and the EMU. The CIU is the customer’s only
interface with the meter, and is a compact unit with a user-friendly
keypad and display. It is usually installed in a convenient
location in the consumer’s home - remote from the
EMU, and is connected to the EMU with a pair of communications
The EMU contains all critical metering,
number decryption and load control functionality. It operates
independently and is immune to any form of tampering on
the CIU interface. The EMU is usually installed in a secure,
locked enclosure, typically a pavement kiosk or pole-mounted
equivalent. It is outside the consumer’s home to facilitate
easy inspection by the utility at any time and to reduce
the opportunity of fraud by tampering. As an option, the
EMU can be supplied with its own LCD display and keypad,
which allows the utility to view important meter parameters
without the need for an interrogation tool.
- Compact meter (EMU) design, with
British Standard layout
- Easy to install and ideal for new
reticulation as well as retrofitting of credit meters
with BS footprints
- Proven keypad technology
- Meter provides valuable information
to help consumers effectively manage and budget their
- Galvanically isolated communication
to CIU for consumer safety
- Tamper detection
- Significant Reverse Energy (SRE)
- Programmable software power limit
- Advanced commissioning / decommissioning
- STS Compliant
- Language independent user interface
- Optional large LCD and keypad at
- Improved sealing against ingress
- Easy to see diagnostic LED’s
on the EMU for Meter state indication and communications
- High surge withstand capability for
areas prone to lightning or other line surges
- SABS 1524 and IEC 62052-11, IEC 62053-21
Principle of operation
The SSP is most suitable for new reticulation.
The communication wires are non-polarised, which simplifies
the installation. In addition, the communication lines are
galvanically isolated from the mains, thereby ensuring
The communication wires can be included
as separate cores in a concentric reticulation cable and
very robust communications interface between the EMU and
CIU over a distance of at least 130 metres.
The EMU is operated via the CIU in exactly
the same way as other meters in the Meter Mate range. User
interaction with the meter and access to meter information
(such as a low credit warning, energy consumption, and load
contactor status) is available using the CIU’s keypad
and large LCD display. The makes use of clear, language-independent
In addition, various audible tones are sounded
under different conditions (e.g. Low Credit Alarm).
Meter status and diagnostic
The EMU includes an LED status indicator.
This allows a technician to view the state of the meter
without the need for specialised interrogation tools or
having to gain access to the consumer’s premises.
Information such as tamper status, power limiting, commissioned
status and credit status are available.
The EMU also features a dedicated diagnostic
LED for the CIU interface. It can indicate the presence
of “Open” or “Short” circuited communication
lines. This is a valuable visual aid that assists the technician
to validate the installation and determine probable fault
As an option, the EMU can be supplied with
a local Human-Machine Interface (HMI). This includes a large
pictographic/numeric LCD, a keypad and an audible buzzer.
This allows the utility to inspect and update various meter
As a customer option, more detailed information
and programming is achieved via the standard interrogation
port at the rear of the EMU.
As a standard feature, the compact Gemini
family offers an IEC 62056-21 compliant optical communications
port. This allows the utility to access a variety of information
stored inside the meter and to upload it to a hand-held
The split configuration of Gemini CSM meters
significantly reduces the risk of tampering. The EMU is
installed in a remote, secure location and is mechanically
sealed against tampering through the use of a factory-sealed
screw plug on the rear panel, and a utility-sealed wire
seal on the front of the meter. The use of these mechanical
seals ensures that there are visible signs of tampering
if unauthorised entry to the system is attempted.
In addition, the units are equipped with
a tamper sensor that will automatically disconnect the power
to the load in the event of tampering.
The meter also has a feature allowing detection
of Significant Reverse Energy (SRE). If the line and load
wires are swapped during installation, the meter will continue
to operate and decrement credit but can be factory programmed
to tamper and disconnect the load should SRE be detected.
The meter has been designed to have a surge
voltage withstand that significantly exceeds the requirements
of both SABS 1524 and IEC 62052-11.
Depending on the environment, the customer
may want to protect the installation by providing additional
surge current protection. The compact Gemini family has
the option of being supplied with a built in surge arrestor
that is capable of sustaining up to 30kA during transients
The communications interface can withstand
voltage surges of 6kV, however it is recommended that one
of the communication lines be earthed at the EMU for additional
protection. Should the customer not want to earth a communication
line during installation, the meter can be fitted with protection
circuitry in the terminal cover.
for more info - SSP Specifications - "allow
time for page to load" )