Product / ZEM-30

The ZEM-30 is a highly accurate, wireless single phase electricity monitor. It can monitor energy consumption patterns in equipment and buildings remotely via the web or local area network, which provides building and energy managers with energy consumption information essential for increasing efficiency, reducing overall power consumption and monitoring usage patterns.

The ZEM-30 has on-board wireless communications for easy installation and minimum disruption to normal operations. It is housed in a waterproof polycarbonate enclosure to suit a wide range of environmental conditions.

Electrical Installation

The ZEM-30 Current Transformer (CT) must be connected as shown the diagram below.

Important Note: Accuracy may be compromised if a large CT is used in a low-current situation, or if the conductor does not pass through the centre of the CT. Accuracy may also be compromised if the CT is not monitoring the same phase as the voltage input to the ZEM-30.

ZEM-30 CT Diagram

Important Note: For consistency, CT’s should be positioned so that the arrow on the base of the CT points in the direction of the electrical load, and away from the source. However, the ZEM-30 reports the absolute value of current and power regardless of CT orientation.

If it is necessary to remove the CT, ensure it is correctly re-attached to the screw terminals as shown in Figure 2. The red wire should be connected to the screw terminal labelled K and the black wire should be connected to the screw terminal labelled L. Internally, the red wire should be connected to the terminal labelled CTX1.

ZEM-30 CT Terminals

Important Note: Each CT is matched to the ZEM-30 it is supplied with – reading accuracy may be compromised if CT’s are mixed up, or if 3rd party CT’s are used.

The voltage input lead on the ZEM-30 is colour coded to conform to European CENELEC standards. The CENELEC standard insulation colours are as follows:

  • L1 – Brown
  • N – Blue
  • Earth – Green / Yellow

Important Note: ZEM-30 voltage signals should be supplied from the phase being monitored (example below). Accuracy will be compromised if this is not the case.

ZEM-30 CT Connection Diagram

Important Note: The ZEM-30 should be connected via a switched junction box and breaker to protect the cable. Also, please ensure that the live connection is made on the same circuit as the neutral connection where residual-current devices (RCD’s) are used.

Mounting instructions

The ZEM-30 is housed in a plastic (Polycarbonate) enclosure sealed to IP67 with 2 cable glands at the bottom, one for the Current Transformer (CT) cable and the other for the mains supply/mains voltage sensing cable.

The ZEM-30 requires 2 screws for wall mounting. These screws can be preinstalled on a vertical surface spaced 122mm vertically apart. The head of the screw should be less than 8.5mm in diameter and the screw thickness should be less than 4.5mm. The screws should be left unscrewed by more than 5mm before installing the enclosure.

Once the keyhole shaped holes in the housing are placed on the screws, the screws can be tightened to secure the housing. The ZEM-30 should be mounted with the cable glands facing downwards.

ZEM-30 Mounting Diagram

Safety

Installation of the ZEM-30 should be carried out only by personnel qualified in the installation of electrical equipment. The ZEM-30 enclosure should only be opened by suitably qualified personnel.  All parts of the circuit within the enclosure must be considered to be at dangerously high mains voltage.

Sensors

The following is a list of all sensors available on the ZEM-30 product range. The reporting mode, reporting interval and logging enabled columns refer to the factory default settings, these settings can be configured from the Gateway.

Note: for “interval” sensors which report (for example) Total kWh, data points will be time stamped at the start of the period that the value relates to. 

Sensor ID

Name

Description

Reporting Mode

Reporting Interval

Logging Enabled

500

Meter Status

Status Bitmask: Brownout:0001, Powerfail:0010, Reset:0100, CommsError:1000

OFF

15

Yes

501

Real Power

Real Power reported in Watts, instantaneous value

OFF

15

Yes

502

Apparent Power

Apparent Power reported in VoltAmps, instantaneous value

OFF

15

Yes

503

Power Factor

Power Factor averaged over the reporting interval

OFF

15

Yes

504

Watt-Hours

Watt-Hours, cumulative

OFF

15

Yes

505

RMS Voltage

RMS voltage, averaged over 30 seconds

OFF

15

Yes

506

Peak Voltage

Peak Voltage measured during the reporting interval

OFF

15

Yes

507

Sag Voltage

Sag Voltage measured during the reporting interval

OFF

15

Yes

508

RMS Current

RMS Current, averaged over 30 seconds

OFF

15

Yes

509

Peak Current

Peak Current measured during the reporting interval

OFF

15

Yes

510

Interval Watt-Hours

Watt-Hours consumed in the reporting interval

Snap to Clock

15

Yes

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