ABB REF601 CE446BB1NH | Feeder Protection Relay, 1 A CT, 4 BI / 6 BO, Modbus RTU

Description

Key Technical Specifications

Product Introduction

The REF601 CE446BB1NH is the kind of relay you find on older MV switchgear where someone needed a compact feeder protection unit that could still talk to SCADA without a full IEC 61850 upgrade. It sits in ABB’s Relion 605 family as a feeder protection and control relay, not just a plain overcurrent trip unit. The “CE446BB1NH” code tells the real story: IEC standard, 1 A CT inputs, 4 BI / 6 BO, Modbus RTU / IEC 60870-5-103 communication, and a universal 24–265 V AC/DC supply.Engineers keep these in service because the function set is predictable. You get three overcurrent stages, two ground-fault stages, thermal overload, phase discontinuity, breaker failure, and auto-reclose up to four shots. The 1 A CT input variant is useful on longer cable runs or where the existing instrument transformers were specified for 1 A secondary. It is not a modern IEC 61850 relay, but for many brown-panel replacements that is exactly why it still works.

Quality SOP & Tech Pitfalls

The Lab Report (SOP)

• Visual inspection: verify order code label “REF601 CE446BB1NH,” serial number, housing damage, terminal block condition, and mounting clips.
• Counterfeit/revision check: confirm ABB branding, label format, and firmware/version plate against OEM documentation.
• Power-up test: apply 24–265 V AC/DC auxiliary supply and verify boot sequence, display, and LED indicators.
• I/O test: check 4 binary inputs and 6 binary outputs with dry contacts; confirm trip/close outputs and IRF/alarm signals.
• Communication test: verify Modbus RTU / IEC 60870-5-103 on RS-485, correct baud rate, device address, and register mapping.
• Protection function spot-check: inject secondary current into phase/ground inputs and confirm pickup, timing, and trip output.
• Settings backup: read and archive existing configuration before shipment.
• Packaging: anti-static bag, rigid box, terminal covers fitted, cable glands protected.

The Engineer’s Warning (Pitfalls)

• Do not confuse “E4” with “A4” or “D4.” E4 means 1 A CT secondary. If your CTs are 5 A, this unit will read low and may not trip correctly.
• The “B” communication option is Modbus RTU / IEC 60870-5-103 on RS-485. It is not IEC 61850. If your SCADA expects IEC 61850 MMS/GOOSE, this relay will not plug in cleanly.
• Auto-reclose settings are dangerous if copied blindly. A cable feeder should not be treated like an overhead line.
• Press-fit mounting looks simple until the panel cutout is worn. Check panel thickness and clip engagement; a loose relay is a vibration failure waiting to happen.

Installation & Configuration Guide

1. Pre-Installation
   • Obtain a switching permit and isolate the feeder.
   • Verify CT secondary circuits are shorted before opening any wiring. ⚠️
   • Photograph existing wiring, CT polarity, binary I/O assignments, communication terminals, and relay settings. ⚠️
2. Removal
   • Label all CT, binary I/O, communication, and auxiliary supply wires.
   • Short CT secondaries with proper shorting blocks or test switches.
   • Release terminal blocks and remove the relay from the panel cutout.
3. Installation
   • Confirm the new unit matches REF601 CE446BB1NH exactly.
   • Check panel cutout dimensions and press-fit clips.
   • Wire CTs with correct polarity; keep ground/zero-sequence CT routing consistent with the original design.
   • Connect RS-485 with correct polarity and termination if required.
4. Power-On & Testing
   • Apply auxiliary supply and verify normal boot.
   • Restore CT circuits only after wiring is confirmed.
   • Check phase currents, ground current, and breaker position indication.
   • Perform secondary injection on overcurrent and ground-fault stages.
   • Test trip/close outputs, binary inputs, and SCADA communication.
   • Record final settings and keep a backup file.

Compatible Replacement Models

Frequently Asked Questions (FAQ)

What does “CE446BB1NH” actually mean?
C = IEC standard; E4 = 1 A CT inputs; 46 = 4 binary inputs + 6 binary outputs; B = Modbus RTU / IEC 60870-5-103 RS-485. The remaining characters define regional/firmware or accessory variants. Confirm with the OEM nameplate.Can I use this on 5 A CTs?
Not directly. The E4 version is for 1 A secondary CTs. If your CTs are 5 A, you need the D4 variant or verified interposing CTs. Otherwise pickup values will be wrong.Does it support IEC 61850?
No. This order code supports Modbus RTU and IEC 60870-5-103 over RS-485. If your substation runs IEC 61850, you will need a gateway or a newer IED.Is auto-reclose safe on cable feeders?
Usually not. Auto-reclose is more appropriate for overhead lines where faults may be transient. On cable feeders, repeated reclosing can worsen insulation damage.Can I hot-swap this relay?
Electrically, the auxiliary supply is wide-range, but you should not replace it while the feeder is energized unless your switching procedure, CT shorting, and trip-circuit design explicitly allow it. Treat CT open-circuit risk as the primary hazard.What should I check before accepting stock?
Order code label, firmware version, physical damage, terminal condition, communication test, and a basic secondary injection report. If the seller cannot provide any test evidence, treat it as unverified.Is this still an ABB-supported product?
REF601 is a legacy Relion 605 series relay. ABB has moved newer projects toward later Relion families. For long-term standardization, plan a migration path, but REF601 remains serviceable as a like-for-like spare when verified.