GE UR-RHH Retrofit-Compatible Relay Output I/O for UR Series

GE UR-RHH Retrofit-Compatible Relay Output I/O Module for Legacy UR Series Systems

The GE Multilin UR-RHH is a relay output digital I/O module designed for the GE Multilin Universal Relay (UR) Series protection and control platform. As legacy UR chassis installations age across substations, switchgear panels, and industrial control cabinets, the UR-RHH has become a critical spare part for engineers managing discontinued module replacements, mid-life system upgrades, and control cabinet modernization projects. NINERMAS maintains verified stock of the UR-RHH to support procurement teams requiring fast turnaround on end-of-life relay hardware without committing to a full platform migration.

The UR Series platform — encompassing protection relays such as the GE Multilin 750/760 Feeder Protection Relay, the GE Multilin 850 Distribution Protection System, and the GE Multilin 469 Motor Management Relay — relies on modular I/O architecture. The UR-RHH occupies a defined slot in the UR chassis backplane, providing hardwired relay contact outputs for trip, alarm, and control functions. When this module fails or reaches end-of-service, the entire protection relay may be rendered inoperable, making verified replacement stock essential for minimizing substation downtime.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

Replacing the UR-RHH within an operational substation or industrial control cabinet requires a structured approach that accounts for the interdependencies between the I/O module and the broader UR platform architecture. Before initiating a replacement, engineers should audit the existing UR chassis configuration — identifying the UR CPU module (which stores all protection settings and handles communication), the UR-DSP Digital Signal Processor module, and any installed UR-8L or UR-4L analog input modules that share the same backplane. Understanding which slots are populated and which carry active wiring is essential to avoid accidental disruption of live protection circuits.

Terminal wiring is a primary concern during UR-RHH replacement. The relay output contacts are wired directly to field devices — circuit breaker trip coils, alarm annunciators, and interposing relays — and the terminal block layout must be documented before any module is removed. Engineers should photograph or transcribe the existing wiring against the panel’s as-built drawings, cross-referencing the UR-RHH’s output contact numbering with the protection relay’s I/O assignment table in EnerVista UR Setup. If the original wiring documentation is unavailable, the UR relay’s settings file can be used to reconstruct the I/O map.

For sites running communication-integrated protection schemes — particularly those using IEC 61850 GOOSE messaging via a UR Communications module supporting fiber or copper Ethernet — the UR-RHH replacement does not affect the communication stack. The GOOSE publisher/subscriber configuration resides in the CPU and communications module, not in the I/O hardware. However, if the site uses hardwired inter-relay logic through the relay output contacts (e.g., direct transfer trip schemes), the output contact continuity must be verified immediately after module installation.

Power supply capacity within the control cabinet should also be confirmed. The UR chassis draws power from a dedicated UR Power Supply module (typically 125 Vdc or 250 Vdc input), and adding or replacing I/O modules does not significantly alter the chassis power budget. However, if the retrofit is part of a broader cabinet upgrade that includes adding a UR-8R additional relay output module or expanding I/O with a UR-4D digital input module, the total chassis load should be recalculated against the power supply module’s rated output.

Sites upgrading from older GE relay platforms — such as the GE MIFII or GE Multilin SR series — to the UR platform as part of a full protection relay modernization will find that the UR-RHH’s relay output architecture provides a familiar hardwired interface that simplifies the transition from legacy discrete wiring schemes. In these cases, the UR-RHH can be configured to replicate the output contact assignments of the predecessor relay, reducing the need for panel rewiring and accelerating commissioning.

Downtime Control During System Migration

Minimizing downtime during a UR-RHH replacement is achievable through careful pre-outage preparation. The most effective strategy is to pre-configure and bench-test the replacement module before the scheduled maintenance window. Since the UR-RHH’s relay output behavior is entirely governed by the settings stored in the UR CPU module, the replacement I/O module requires no independent configuration — it will assume its assigned function as soon as it is seated in the correct chassis slot and the relay is powered.

The recommended sequence for a controlled replacement is: (1) export and archive the current relay settings file using EnerVista UR Setup before any hardware is touched; (2) de-energize the output circuits connected to the UR-RHH’s relay contacts, using the control cabinet’s test/isolate switches where available; (3) remove the defective module and install the replacement UR-RHH in the same chassis slot; (4) restore power and allow the UR relay to complete its self-test sequence; (5) perform a functional output contact test using the relay’s force output feature in EnerVista to confirm each contact operates correctly; and (6) restore the output circuits and verify alarm and trip signal continuity to the connected field devices.

For sites where the UR relay is part of a redundant protection scheme — for example, a dual-relay busbar protection arrangement — the standby relay can be placed in service while the primary relay undergoes the UR-RHH replacement, eliminating any gap in protection coverage. This approach is strongly recommended for critical feeders, transformer bays, and generator protection applications where continuous protection is a regulatory or operational requirement.

NINERMAS pre-shipment testing ensures that every UR-RHH module is functionally verified before dispatch, reducing the risk of receiving a non-functional replacement and the associated additional downtime. All modules are shipped with a test report and are covered by a 12-month warranty from the date of shipment.

Retrofit Support FAQ

Q1: Is the GE UR-RHH a direct drop-in replacement for a failed relay output module in my existing UR chassis?
In most cases, yes. The UR-RHH is designed to occupy a specific slot in the UR Series chassis backplane, and because all relay settings and I/O assignments are stored in the UR CPU module, the replacement module does not require independent programming. However, you should confirm the chassis slot designation and the specific UR-RHH variant (contact configuration) matches your existing installation before ordering. Contact NINERMAS with your chassis model and slot number for pre-order verification.

Q2: Will replacing the UR-RHH affect my existing relay protection settings or communication configuration?
No. The UR-RHH is a passive I/O module — it does not store protection settings, communication parameters, or logic configurations. All of these reside in the UR CPU and Communications modules. After installing the replacement UR-RHH, your relay will resume normal operation with the existing settings intact. We recommend exporting a backup of the settings file via EnerVista UR Setup before any hardware work as a precautionary measure.

Q3: What pre-shipment testing does NINERMAS perform on the UR-RHH before dispatch?
Every UR-RHH module supplied by NINERMAS undergoes functional contact verification testing prior to shipment. This includes continuity testing of all relay output contacts and visual inspection for physical damage or connector wear. A test record is included with each shipment. All modules are covered by a 12-month warranty from the date of shipment, and NINERMAS maintains ongoing stock to support rapid replacement needs without extended lead times.

Q4: Can NINERMAS supply other UR Series modules if I need to upgrade additional I/O or replace other components in the same chassis?
Yes. NINERMAS stocks a range of GE Multilin UR Series modules, including CPU modules, communications modules, digital input modules, analog input modules, and power supply modules. If your retrofit project requires multiple components — for example, replacing both the UR-RHH and an aging UR Power Supply module, or adding a UR-4D digital input module to expand I/O capacity — NINERMAS can consolidate the supply into a single shipment to reduce logistics complexity and downtime risk. Contact our team at sale@ninermas.com with your full bill of materials for a consolidated quote.