Schneider Electric RMNF22TB30 3-Phase Monitoring Relay

RMNF22TB30 three-phase monitoring relay explained

RMNF22TB30 is a Harmony Control Relays unit that watches a three-phase supply and switches two changeover outputs when something goes wrong. Its datasheet names it the RMNF22 NFC multifunction relay with a 208–480 V AC range, and it is built to supervise phase sequence, phase loss, overvoltage, undervoltage, over- and underfrequency and asymmetry in one 22.5 mm wide module.

The "NFC" in the name matters in practice: settings are not made with front dials but by holding a compatible phone or tablet against the relay and using the EcoStruxure Industrial Device app named in the datasheet. The version without a diagnostic button is the one described for RMNF22TB30.

Seven Star LLC supplies RMNF22TB30 in Oman and the GCC as an independent supplier in Muscat; the datasheet we hold is dated 7 Nov 2026.

Fit, approvals and related relays

Approvals listed for RMNF22TB30 are CE, UL, CSA, CCC, EAC, RCM and UKCA, with EMC testing to IEC 61000-6-2 and 61000-6-4 and radio-equipment directive 2014/53/EU noted because of the NFC link. For the RMNF family, other part numbers may differ in range or output contacts; confirm the datasheet of any alternative rather than assuming equal settings.

Pairing with a contactor or motor starter is by the two output contacts, so check that the coil of the downstream device stays within the 8 A and AC-15 limits of the relay.

Selection and ordering checklist for RMNF22TB30

Check the following before ordering RMNF22TB30:

• Supply system: line-to-line 208–480 V AC (or 120–277 V AC line to neutral) at 50 or 60 Hz, with a neutral wire available if you want N-referenced monitoring.
• Which faults must be alarmed and whether both output relays are needed, for example one for trip and one for warning.
• Time-delay needs, to ride through short sags without nuisance tripping.
• Availability of an NFC-capable phone with the required Android or iOS version for configuration.
• Space: 22.5 mm of DIN rail width and terminals for up to 2 × 2.5 mm² solid or 2 × 1.5 mm² flexible with ferrules.

Where RMNF22TB30 fits in Oman and the GCC

Three-phase supervision protects motors on desalination feed pumps, cooling-water circulation, fire-water and booster sets, and HVAC chillers where grid disturbances and long feeder runs are common. Generator-backed facilities also benefit from the frequency monitoring when changing between mains and standby power.

The datasheet lists operation from −30 to 60 °C, IP40 housing and pollution degree 3, so RMNF22TB30 belongs in a switchboard or enclosure instead of open air. In coastal Oman, enclosure sealing and anti-condensation measures are the main factors to plan around.

What each monitored fault means

RMNF22TB30 evaluates the three line voltages as true r.m.s. values in a 150 ms cycle and compares them with thresholds you set:

• Phase sequence: detects a reversed rotation order, which matters for pumps, compressors and conveyors that must not run backwards.
• Phase failure: detects a lost phase, with a fixed 3 % hysteresis on the nominal voltage.
• Overvoltage and undervoltage: adjustable alarm levels between 166 and 576 V line to line (96–332 V line to neutral).
• Frequency: adjustable over- and underfrequency alarm between 45 and 66 Hz, useful on generator-fed sites.
• Asymmetry: adjustable between 5 and 150 V, with the percentage setting of 2–20 % of Un as the threshold input.

On RMNF22TB30, a time delay of 0.1 s to 60 minutes can be applied to the fault, and the datasheet gives accuracy as ±3 % for delays from 10 s to 60 min and ±300 ms below 10 s.

Installation, setup and maintenance

RMNF22TB30 mounts on a 35 mm rail in any position without derating. Terminal torque is 0.6–1 N·m. The supply is non self-powered, which means the relay draws its power from the monitored lines or neutral rather than from an auxiliary 24 V source, with consumption stated as 4 VA at 480 V AC, 60 Hz.

During commissioning, enter the nominal voltage and thresholds through the app, then test by lifting one phase on a safe, isolated test circuit to confirm the PL LED and relay response. The datasheet gives a power-on delay of 650 ms, so allow for it in interlocking logic.

Maintenance of this unit is limited to periodic function tests and retightening terminals. Keep a record of the saved settings so a replacement can be configured quickly.

Outputs and indicators on RMNF22TB30

This unit has two C/O contacts (R1 and R2), rated 8 A, 250 V AC maximum, 2000 VA, with a minimum switching current of 10 mA at 12 V DC. Utilisation categories listed are AC-1 at 250 V 8 A and AC-15 at 250 V 3 A, plus DC-1 at 24 V 5 A and DC-13 at 24 V 2 A.

LEDs make fault finding quick: a green Un LED for supply, amber R1 and R2 LEDs that blink while timing and stay on when energised, and separate red alarm LEDs for phase loss (PL), phase sequence (PS), undervoltage (UV), overvoltage (OV), underfrequency (UF), overfrequency (OF) and asymmetry (ASYM). Since the unit has no diagnostic button, review of past faults is done through the NFC app.

RMNF22TB30 technical specifications

Information to send with an RFQ

To quote this unit, please provide:

• Part number RMNF22TB30 and quantity.
• System voltage and frequency, with or without neutral.
• Required fault functions and delay settings, if you want us to note them.
• Delivery location in Oman or the GCC and any project reference.

Documents and quotation

The datasheet for this unit is attached to this page (document dated 7 Nov 2026). Please treat it as the reference for every figure above, and tell us if your project specification asks for anything the datasheet does not state.

Send the part number, quantity, required delivery point and any project reference through the quotation form or by email. Seven Star LLC is an independent industrial supplier based in Muscat, serving customers across Oman and the GCC, and we reply with availability and lead time for this exact part number.