Selec EM306-C-D Dual-Source Mains/DG Energy Meter, RS485

One meter for both utility and generator energy

The Selec EM306-C-D is the dual-input version of the EM306 three-phase energy meter. A digital input tells the meter whether the load is being fed from the utility (Mains) or from the diesel generator (DG), and it keeps separate kWh, kVArh and kVAh totals for each source plus a Mains+DG total, all readable over RS485 Modbus RTU.

That removes the need for two meters and a changeover scheme where a site wants to know what a generator run actually cost in energy. The 96 x 96 mm case has a single row of six seven-segment LED digits, 0.56 inch high, and the meter also reports kW, kVAr, kVA and power factor.

Features split by model

• EM306 (plain code): 3-phase active energy meter, SMPS supply 85 to 276 V, single pulse output
• EM306-C-D: dual input (Mains/DG), kWh, kVArh, kVAh, kW, kVAr, kVA, PF and RS485 Modbus RTU

Technical specification

Measurement (EM306-C-D values where the datasheet separates them)

Supply, communication and mechanical

EM306 versus EM306-C-D

This page is for EM306-C-D. Because the datasheet text on supply range (85 to 276 V) and the ordering table (100 to 240 V AC) are written differently, confirm the supply voltage on your order.

Wiring notes and the digital input

The manual shows the Mains/DG digital input wired from an auxiliary contact on the changeover; the meter then books energy to the active source. Total registers for Mains+DG are available over Modbus (addresses around 30172 to 30182 in the manual).

• Panel mount; use lugged terminals and 0.5 to 2.5 mm2 copper.
• When the energy value passes 999999 the display changes resolution according to the CT x PT ratio, so note the scaling when reading the register over Modbus.
• A short-circuiting CT block is good practice before touching CT wiring.

Generator-backed sites in the Gulf

Oil and gas camps, remote pump stations, telecom shelters and data rooms often run on utility power with a standby or prime-power diesel generator. A dual-source meter lets maintenance teams reconcile fuel use with the kWh actually delivered by the generator and report utility consumption separately. The IP54 rating applies to the front of the panel meter, not the installation.

Selection and installation notes

A panel energy meter or instrument is selected from the wiring system, the current range and the outputs needed. Check whether it is direct-connected or CT-operated, set the CT ratio before reading, connect the voltage inputs through suitable fuses, respect the phase order and the polarity of the CTs and set the communication parameters when it is read by a BMS or energy system. Compare the first readings with a reference meter and fit it in a panel with the cut-out size on the data sheet.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Related parts

You supply the CTs, the changeover auxiliary contact for the digital input and an RS485 gateway if the data goes to a BMS or SCADA. Use the MFM384 or MFM376 for sites that need voltage, current and THD displays in place of an energy-only face.

Frequently asked questions

What does the D in EM306-C-D stand for?

The datasheet describes EM306-C-D as the dual input (Mains / D.G.) meter.

How many display digits are there?

One row of six digits on a 7-segment LED display, 0.56 inch high.

Which communication is available?

RS485 Modbus RTU, on the EM306-C-D only; the plain EM306 has a pulse output.

What energy class is printed?

Active energy Class 1 and reactive energy Class 2 for the C-D version.

What front rating does it have?

IP54 as printed on the datasheet.

Documents and quotation

The datasheet hosted here covers both the EM306 and EM306-C-D. Ask for a quotation naming EM306-C-D and the CT ratio you plan to use. Please verify stock, supply voltage and approvals before you order. Seven Star LLC acts as an independent supplier from Muscat. More products in this range are listed under Metering Systems.