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Installation
Powering the MD-P1 and MD-P1D Power Meters
23
Siemens Industry, Inc. 125-201
09/30/2019
Powering the MD-P1 and MD-P1D Power Meters
The MD-P1 and MD-P1D Power Meters are self-powered from the L1 and L2 lines.
When 80 to 600 Vac or Vdc is placed across the L1 and L2 wires, the three phasing
LEDs begin to flash in sequence.
For accurate measurements, the neutral conductor must be installed.
MD-P1 and MD-P1D Power Meters Single-Phase
Connections
The MD-P1 and MD-P1D Power Meters can be used to monitor single-phase loads.
There are several guidelines to keep in mind about this type of connection:
1. The power meter is powered from a potential between L1 and L2. This can be
phase-to-phase (230V) or phase-to-neutral (115V). With a single-phase 230V
panel, the L1 and L2 voltage leads are connected between the L1 and L2 voltage
sources. With a 115V circuit, the L1 voltage lead is connected to the L1 “hot lead,”
and the L2 voltage lead is connected to neutral.
2. Each CT must be paired with the correct voltage source. The current and voltage
must be in-phase for accurate measurements. For instance, CT 1 would monitor
branch circuit supplied by voltage source L1, and so on.
3. The neutral must be connected because MD-P1 and MD-P1D Power Meters use
line-to-neutral measurements for all calculations.
Typical 230V Single-Phase Panel Setup
Provide wiring from the red terminal block to the panel:
● L1 Terminal to Voltage L1 (black)
● L2 Terminal to Voltage L2 (red)
● White Neutral voltage lead to Neutral.
CT1 will monitor L1 loads and CT2 will monitor L2 loads. Based on the above
guidelines, CT3 can be used if the blue L3 voltage lead is connected to either L1 or L2.
If voltage leads L3 and CT3 are in-phase, the MD-P1 and MD-P1D Power Meters will
provide correct kW readings. If the blue L3 voltage lead is connected to the L2 voltage
source, then CT3 can monitor any L2 branch circuit. Or, if the blue L3 voltage lead is
connected to the L1 voltage source, then CT3 can monitor any L1 branch circuit.
Typical 115V Single-Phase Panel Setup
Provide wiring from the red terminal block to the panel:
● L1 Terminal to Voltage L1 (black)
● L2 Terminal to Voltage L2 (red)
● White N voltage lead to neutral.
The power supply is across the black (L1) and the red (L2) lead; therefore, the red (L2)
lead must also be connected to the neutral line.
CT1 will monitor the L1 load. CT3 can be used if the blue L3 voltage lead is connected
to L1. CT3 could then monitor any L1 branch circuit.