GE MIFIIPI | MIF II Digital Feeder Protection Relay Unit

Description

• Brand: GE Multilin
• Full Model Number: MIFIIPI
• Product Family: MIF II Digital Feeder Relay
• Lifecycle Status: Obsolete / Manufacturing Discontinued
• Core Function: Distribution feeder protection and control
• Top 3 Technical Specs: Phase and ground TOC/IOC protection; Thermal image protection; Modbus RTU via RS485
• Additional Functions: Breaker open/close control; Four-shot autorecloser on applicable configurations; Event recording; Oscillography
• User Interface: 2 × 16-character LCD; 6 LED indicators
• Communication: Front RS232; Rear RS485; Modbus RTU up to 19,200 bps
• Stock & Condition: Physical inventory subject to same-day confirmation; New Surplus or Tested Inventory by available lot
• Procurement Note: Exact suffix required for CT range, control power, options, recloser configuration, language, and environmental coating

Obsolescence & Supply Chain Deep Dive

MIF II manufacturing has been discontinued by GE, so plants still running this relay face a familiar maintenance problem: the failure of one protection device can turn a routine spare-parts requirement into an extended sourcing event. GE identifies the MIF II as a legacy digital feeder relay for distribution protection, with additional use as backup protection for transformers, busbars, generators, and large motors. Its protection set includes phase and ground time-overcurrent and instantaneous-overcurrent functions, thermal image protection, configurable I/O, event recording, and optional recloser capability.

For an installed MIF II system, retaining the same configuration can reduce TCO because the existing panel arrangement, field wiring, protection philosophy, and operator familiarity do not have to be replaced merely because OEM production has ended. That matters most where the alternative is a broader relay migration. GE’s retrofit documentation shows that moving from MIF II to the 350 family requires order-code comparison, setting-file conversion, and dedicated wiring mapping rather than a simple one-for-one assumption. (For emergency maintenance, a verified surplus relay can therefore avoid a larger engineering change window.)

Compatibility & Replacement Matrix

Engineering approval point: Do not approve the purchase from the shortened identifier MIFIIPI alone. GE’s published MIF II order-code examples contain multiple configuration fields, and the replacement must be matched to the installed relay’s complete order code. The control-power specification is also configuration-dependent; GE documentation lists 24/48 VDC and 110/250 VDC or 110/230 VAC ranges for applicable variants.

Field Traps — Watch Out

• Order-Code Mismatch: The MIF II firmware selector requires configuration selections for phase/ground arrangement, curve shapes, phase range, ground range, language, options, recloser, power supply, and environment. A relay with the same family name can therefore have different electrical behavior or available functions.
• Firmware and Settings Compatibility: GE states that MII Setup 1.10 or later is required to load firmware 4.01 or newer. Verify the installed firmware before flashing a replacement and preserve the existing settings file before commissioning.
• Output Contact Configuration: MIF II output contacts can be configured through hardware jumpers. Confirm NO/NC configuration before energizing the control circuit.

GE MIFIIPI

Quality Assurance & Testing SOP

Every supplied unit should pass a documented incoming and pre-shipment inspection sequence before release.

• OEM Anti-Counterfeit Visual Inspection: Compare GE/Multilin markings, model label, serial information, enclosure construction, connector arrangement, PCB identifiers where accessible, and label quality against known MIF II documentation.
• Nameplate Verification: Record the complete order code rather than relying on the shortened purchasing reference. Match phase/ground configuration, control-power range, option package, recloser configuration, and environmental designation.
• Mechanical Inspection: Check housing, mounting points, terminal blocks, communication ports, LCD window, keypad, LED indicators, and connector integrity.
• Power-On Self-Test (POST): Energize using the correct rated control power; verify startup self-monitoring, display operation, normal status indication, and absence of internal alarm conditions. For front panels carrying dedicated ERR/RUN indicators, confirm RUN status and no ERR indication.
• Communication Test: Establish communication through the front RS232 interface and, where applicable, the rear RS485 interface; verify stable Modbus RTU communication and readable device data. GE identifies the front RS232 and rear RS485 interfaces as MIF II communication ports.
• Protection Function Test: Apply controlled secondary current inputs and verify configured phase and ground overcurrent pickup, timing response, and thermal-image behavior against the applicable settings sheet.
• I/O Load Testing: Exercise digital inputs and output contacts under controlled test conditions; confirm contact state changes, trip signaling, breaker-control logic, and configurable I/O response where fitted.
• Event and Oscillography Check: Confirm event recording and waveform functions on configurations where these features are installed. GE documentation identifies event recording and oscillography as available on applicable MIF II option models.
• Final QA Record: Record serial number, full order code, firmware revision, applied control voltage, communication test result, protection-test results, photographs, and packing inspection before shipment.

Procurement & Lifecycle FAQ

Is the GE MIFIIPI genuinely in stock, and what is the cutoff for emergency shipping?

Physical availability should be confirmed against the actual warehouse unit before the PO is released, especially because MIF II is discontinued. Emergency dispatch can generally be arranged when the unit, payment, destination, and shipping instruction are confirmed before the applicable warehouse carrier cutoff; the exact cutoff should be stated on the quotation because it varies by destination and service level. GE confirms that MIF II manufacturing has been discontinued.

How do you verify the condition and authenticity of an obsolete or surplus MIF II relay?

The purchasing file should include the unit’s full nameplate/order code, serial information, detailed photographs, physical inspection records, power-up results, communication results, and functional test data. For surplus equipment, those records provide substantially more useful traceability than a condition label alone. GE’s own commissioning documentation includes visual inspection, power-supply testing, communications testing, relay settings, contact inputs, contact outputs, and metering checks as commissioning activities.

Are firmware compatibility issues important before issuing the PO?

Yes. MIF II firmware selection depends on the relay configuration, and GE states that MII Setup 1.10 or later is required for firmware 4.01 and newer. Engineers should capture the existing firmware version and settings before replacing the device rather than assuming every MIF II variant can use the same firmware package.

Can MIFIIPI be replaced directly by a GE 350 relay?

Not as an automatic drop-in substitution. GE’s retrofit documentation provides MIF II-to-350 wiring mappings and describes setpoint-file conversion, which indicates a defined retrofit process rather than a simple device swap. Order-code differences must also be reviewed because some MIF II functions and options do not map identically to the 350 family.

What warranty and return terms should procurement require?

The quotation should state the exact warranty period, inspection window, RMA procedure, and return exclusions before the PO is issued. For an obsolete protection relay, the warranty scope should distinguish hardware failure from incorrect settings, incompatible control power, field-wiring errors, or application changes. A complete pre-shipment test report should be retained with the purchase file so any post-delivery claim can be evaluated against documented test results.