1. Installer Guide
  2. Flexible (Rogowski) sensors
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Flexible (Rogowski) sensors PDF

Energy Monitor + EMS Installer Guide

Flexible (Rogowski) sensors

The flexible-sensor kit in depth: when to use it, kit parts, mounting the power supply and integrators, coil orientation and centering, cabling and flex-specific troubleshooting.

The flexible kit replaces the two 200 A split-core main CTs with two flexible Rogowski coils. Everything else (the monitor, harness, antenna and the two 50 A branch CTs on ports 3 and 4) is the same as the split-core kit. This section covers what's different. The shared steps are in Install the Energy Monitor.

When to use the flexible kit

  • Use it wherever split-core CTs won't close fully around the service or feeder conductors.
  • Meter-mains usually need it. So do tight gutters, large or alternating conductors, and service disconnects that leave no straight run.
  • Decide at scoping, from the panel photos. Don't start a flex job until the flexible sensors are on site.

Kit parts

Part Qty What it does
Flexible Rogowski coil with integrator 2 One coil per hot conductor. The integrator turns the coil signal into a reading for the monitor
Signal wire with 4-pin plug 2 Plugs into each integrator. Carries the twisted signal pair to port 1 or 2 (2-pin plug) and the 12 V red and black leads
12 V sensor power supply (Mean Well IRM-30-12ST) 1 Powers both integrators. Black and red 12 V output splits to both signal wires. Input: black to L1, white to L2
Wago lever connectors, wire nuts, splicing wire — Two 5-port Wagos: one for L1, one for L2
Flexible kit: the Energy Monitor with two flexible Rogowski coils (red and black) on their integrators, the 12 V sensor power supply and signal-wire harness, two branch CTs, the voltage harness, the Wi-Fi antenna, Wago connectors, wire nuts and splicing wires

How the harness connects

Flexible sensor harness: each coil's lead is coiled and zip-tied, then enters its integrator. Each integrator takes a 4-pin plug wired + Power red, − Power black, − Output black, + Output white. The red and black 12 V leads join the power supply's output at a solder and heat-shrink split; the black and white signal pair runs to Energy Monitor port 1 (CT 1, black coil) or port 2 (CT 2, red coil). The power supply's AC input is black to L1 and white to L2. An inset shows the load arrow on the coil head.
  • Each 4-pin plug goes into one integrator. It carries that coil's twisted signal pair and one red and one black 12 V lead.
  • 12 V output: one black and one red wire leave the power supply and split at a soldered, heat-shrunk joint, so each plug gets one black and one red.
  • AC input (the other end of the power supply): black to L1, white to L2.
  • Signal pairs: CT 1 to port 1, CT 2 to port 2. On the monitor, ports run 1 to 4.

Warning

Use production kits only: the harness, power supply and integrators exactly as shipped. Don't mix in sample parts, and don't use any third-party coils, integrators or power supplies.

Mount the power supply and integrators

  1. Plan the layout before you mount anything: the monitor, the power supply and the two integrators all go inside the panel.
  2. Keep all of them at least 50.8 mm (2 in) from live parts: primary conductors, terminals and lugs. Insulated cables are fine.
  3. Put the integrators where each coil's cable reaches its integrator, and each signal cable reaches ports 1 and 2, without strain and without cutting or extending anything.
  4. Don't mount anything to an energized part, over ventilation openings or in the path of breaker arc venting.

Wire the power supply

The power supply's AC input has two leads: black to L1 and white to L2. Both land with the monitor's harness on the same two breakers. Full wiring with photos is in Step 5.

  • Black (L1): join the black input lead with the monitor's black (L1) in the L1 Wago.
  • White (L2): join the white input lead with the monitor's red (L2) in the L2 Wago. It never goes on the neutral bus.
  • AFCI/GFCI breaker: black goes in the L1 Wago to the breaker's hot terminal; white goes in the L2 Wago with the monitor's red (L2) to the adjacent single-pole breaker.

The monitor and the power supply together draw less than 1.5 A.

Note

Battery on CT 3? Blue L3 goes in the L1 Wago.

If CT 3 monitors a battery, the monitor's blue (L3) must connect to black (L1): put it in a spare port of the L1 Wago. L3 is CT 3's voltage reference: without it, the monitor can't tell the battery charging from discharging. The only other use for L3 is the third phase of a 3-phase 208Y/120 V service. Otherwise cap it. See Blue L3.

What goes in each Wago

Step 5 case L1 Wago (5-port) L2 Wago (5-port)
5a. Empty breakers Splicing wire to the L1 pole, black (L1), power supply black, blue (L3) if a battery is on CT 3 Splicing wire to the L2 pole, red (L2), power supply white
5b. Splice into in-use breakers Splicing wire, circuit wire, black (L1), power supply black, blue (L3) if a battery is on CT 3 (fills the last port) Splicing wire, circuit wire, red (L2), power supply white
5c. AFCI or GFCI breaker Splicing wire to the breaker's hot terminal, black (L1), power supply black, blue (L3) if a battery is on CT 3 Splicing wire to the adjacent single-pole breaker, red (L2), power supply white

White (N) never goes in a Wago: it lands on the neutral bus, or on the breaker's neutral terminal for 5c.

Connect power and signal

  1. Plug a signal wire's 4-pin plug into each integrator. Push it fully home and tighten the screws to 0.34 N·m (3.0 lb-in). The plug carries both the signal pair and the 12 V leads.
  2. Route each twisted signal pair to the monitor and plug its 2-pin plug into port 1 (CT 1) or port 2 (CT 2). Mind the polarity. Ports 1 and 2 are for the mains on every install.
  3. Port 1 on the L1 conductor is recommended, not required.
  4. Keep the signal cable leads twisted.
Integrators and coils on the mains

Install the coils

Coil arrow points toward the load
  1. Release the latch to open one end of the coil.
  2. Wrap the coil around one hot service or feeder conductor. Never the neutral.
  3. Lock the end back into the clasp. It must click closed: an open or half-latched coil reads low or erratic.
  4. Turn the coil so the arrow points toward the load: into the panel the breaker feeds.
  5. Zip-tie the coil head to the conductor. That keeps the coil from sliding or turning, so the arrow stays pointed toward the load.
  6. Repeat on the second hot conductor.

The placement rule is the same as for split-core CTs: both hots of the breaker the EMS protects, just above or just below it, nothing tapped in between. See Step 7 and Wiring diagrams.

Danger

⚡ DANGER: The service mains are energized! Wrapping a coil means working right at the live service conductors. Wear insulated gloves and eye protection.

Cabling rules

  • Don't cut, splice or extend the coil cable, the integrator signal cable or the 12 V power cables. They are calibrated sensor components.
  • Coil the excess and tie it off. Keep it away from live terminals and buses.
  • Keep every cable inside the panel where the monitor is mounted.

Flex troubleshooting

Symptom Likely cause Fix
Both mains read zero The power supply has no power Check its breaker is on and both input leads are secure in the L1 and L2 Wagos
One main reads zero That integrator's 12 V harness or signal cable isn't seated Reseat the 12 V plug in the integrator and the signal plug in port 1 or 2
A main reads negative while the home is drawing power The coil faces the wrong way Turn the coil so the arrow points toward the load. (With solar or a battery, rule out export first. See Readings are negative.)
A main reads low or jumps around Coil not fully latched, or the coil has slid or turned Relatch the coil and zip-tie the coil head to the conductor
Mains read but the charger channel doesn't CT 4 problem, not the flex kit See Readings don't match

More symptoms are in Troubleshooting.

Something wrong or unclear on this page? Email support@getneocharge.com. Rev 005 is the controlled copy.