Product Overview

The ABB OS250D12P​ (order/article number 1SCA022726R8380) is a switch disconnector fuse (SDF) belonging to ABB’s OS-series low-voltage switch-fuse family, engineered as a combined isolation switch and fuse-carrier unit for 690 V AC distribution, motor-feeder, drive-infeed, and UPS/PDU isolation duties in industrial MCCs, machine-panel main switches, and building-distribution subboards. The “OS” prefix designates ABB’s fused-switch platform (as opposed to the “OT” series which is switch disconnector withoutfuse), the “250” is the frame’s rated operational current (250 A at 690 V AC, AC-23A utilization category), the “D” denotes NH DIN-blade fuse compatibility (accepting NH1 / NH2 class blade fuses in the 250 A frame range), “12” is ABB’s internal variant/width code for this article, and the “P” suffix indicates the unit is supplied with ABB’s standard red/yellow rotary operating handle (padlockable in OFF, I–O labeling, door-coupling capable) — whereas the base OS250D12 (no P) would be the bare switch-fuse body for panel builders fitting a separate external handle. The ABB OS250D12P​ therefore arrives as a “fit-and-go” unit: DIN-rail or panel-mount switch body, three NH fuse carriers (3-pole; neutral passes through unblown on the standard 3P build, 4P version if /4 specified), red/yellow rotary handle, and padlockable OFF positions (1–3 locks typical) so maintenance can LOTO the feeder without removing the fuse.The ABB OS250D12P​ is positioned in the OS family between the OS160D07P (160 A) and OS400D12P (400 A), making the 250 A frame the sweet spot for 132–200 kW motor feeders (400 V) and for 690 V drive-infeed to mid-size ACS800/ACS880 MD chassis. Short-circuit current rating with properly coordinated gG or aM NH fuses is typically 50 kA (some OS variants rated to 80 kA at 690 V with ABB’s fuse selection — confirm against the specific 1SCA022726R8380 datasheet), and the unit is bidirectional (line/load reversible) provided the panel designer respects the fuse-carrier orientation. The switch body is IP20 (touch-safe, DIN/panel internal), while the rotary handle穿透 the cabinet door via a door-coupling kit (sealing collar) achieving IP54 on the handle side — important for MCC rooms where the operator never opens the live compartment, only turns the yellow-handled, red-knobbed rotary from outside.Installed base of OS250D12P​ is substantial across metals, mining, marine, cement, water/WW, data-center power, and OEM machinery panels — anywhere a 250 A, 690 V class fused isolation is needed and the panel builder/standardizer wants ABB’s OS family consistency (same handle look/feel from 32 A up to 630 A across the OS/OT range). The article 1SCA022726R8380 is current/active in ABB’s LV catalog (OS series is ongoing, unlike some mature drive/DCS spares we’ve covered), so new-from-ABB availability is normal, but the OS250D12P​ also appears on spare BOMs for plants with frozen panel designs that used this exact article 5–15 years ago and keep a hot-spare per MCC section.

 

Technical Specifications

Parameter Name	Parameter Value
Product Model	OS250D12P​
Article Number	1SCA022726R8380
Manufacturer	ABB (Low Voltage Products)
Product Type	Switch Disconnector Fuse (SDF) / Isolation Switch + Fuse Set
Rated Operational Current (Ie)	250 A (AC-23A at 690 V)
Rated Operational Voltage (Ue)	≤ 690 V AC, 50/60 Hz
Fuse System	NH DIN-blade (D), accepts NH1 / NH2 class fuses (gG, aM, etc.)
Poles	3-pole (line-side fused, neutral straight-through on std 3P; 4P / 3P+N available on OS250 family — confirm 1SCA022726R8380 exact pole count)
Short-Circuit Rating (with fuses)	~50 kA (gG NH coordination; verify against ABB fuse selection table for 1SCA022726R8380)
Mounting	35 mm DIN rail and/or panel (OS DIN-body with panel-mount adapters)
Handle	Red/Yellow rotary (P-suffix), padlockable OFF (1–3 locks), I–O labeling, door-coupling capable
Protection (body)	IP20 (cabinet internal)
Protection (handle, with door kit)	IP54 (sealing collar through door)
Operating Temperature	–25 … +55 °C (typical LV-switch range)
Connection	Screw terminal / bolt terminal (accepts 35–240 mm² depending on lug kit)
Standards	IEC 60947-3, IEC 60269 (fuse), UL/CSA where applicable on OS series
Sibling Variants	OS160D07P (160 A), OS400D12P (400 A), OT250E03P (same frame, no fuse)

 

Main Features and Advantages

Switch + Fuse Consolidated in One DIN Body.​ The ABB OS250D12P​ does what two separate devices (an isolator + a fuse-holder) would do, in one OS-series footprint. The three NH fuse carriers (NH1/NH2 sized to the 250 A frame) seat into the switch body; when the handle turns to OFF, the contacts part andthe fuse carriers become accessible (pull-out style, touch-safe when off) — so the maintenance tech doesn’t need a separate fuse-puller or a separate isolator LOTO. The “D” in the model (NH DIN-blade) matters: NH fuses (DIN-blade, size 000/00/0/1/2/3) are the European/industrial standard for 160–630 A feeders, with gG (general) for distribution and aM (motor) for motor feeders — the OS250D12P‘s 250 A frame typically takes NH1 (up to ~160 A fuses) or NH2 (up to ~250 A fuses) depending on the fuse amp selected, and the “12” variant code tells ABB which fuse-carrier length/footprint is fitted. Having NH-blade (rather than cylindrical BS88 or D0/D02) means local spares cribs already stock NH1/NH2 gG and aM fuses for the rest of the plant MCC, and the OS250D12P​ taps that same crib — no new fuse family to manage.Red/Yellow Rotary Handle, P-Suffix = “With Handle.”​ The “P” in OS250D12P​ is the differentiator vs the bare OS250D12: the P arrives with ABB’s red/yellow rotary handle pre-fitted (or as a matched kit, depending on shipment batch — some regions ship OS250D12 + handle separate but ordered as -P). Yellow handle body (visible from distance: “yellow = handle present, switch in section”), red rotary knob (I = red visible through window, O = yellow shows), I–O labeling per IEC 61310, and padlockable in OFF (1–3 standard padlocks, shackle ≤ 8 mm). This is the LOTO enabler: a motor-feeder to an ACS800 MD chassis can be isolated at the OS250D12P​ upstream, padlocked OFF by the electrician, and the drive’s 24 V control (NMPP-02 / NXPP-02C) can stay alive for diagnostics without the 690 V present — the padlock proves to the restarting tech “this feeder is LOTO’d.” The handle also supports door-coupling: a sealing collar (ABB accessory) mounts in the cabinet door cutout, the rotary shaft passes through, and the OS250D12P​ operates from outside the live compartment — the MCC door stays closed during normal ON/OFF, meeting IEC 61439-2 compartmentalisation.50 kA+ Short-Circuit Rating with Proper Fuses.​ The OS250D12P​ switch body alone is not a short-circuit device — its 250 A contacts would blow at 10 kA without help — but paired with NH gG fuses (selected per ABB’s coordination table for 1SCA022726R8380), the SCCR jumps to ~50 kA at 690 V (some OS variants / fuse combos push 80 kA — verify against the specific article datasheet). This is why the “isolation switch + fuse set” description matters: the fuses do the fault-clearing, the switch does the isolating-and-being-touch-safe. On a 200 kW motor feeder (400 V, ~360 A starting), an NH2 250 A gG upstream of the OS250D12P​ clears a bolted-fault in <0.1 s, protecting both the OS250D12P​ contacts and the downstream cable. For motor duty, the plant specifies aM (motor-protecting) NH fuses instead of gG — the aM curve is more tolerant of motor inrush (6–8× FL for 5–10 s) without nuisance-blowing, and the OS250D12P‘s NH carriers accept either gG or aM — same carriers, different fuse link.DIN Rail + Panel Flexibility.​ The OS250D12P​ body clips onto 35 mm DIN rail (the same rail that carries NMPP-02, NPOW-41, NTAI05 in a DCS MCC), but the OS series also supports panel-mount (through-bolt) via adapters — so the same OS250D12P​ BOM line works in a DIN-layout MCC (European/OEM style) and in a back-panel-bolted MCC (North American/legacy style). The fuse-carrier pull-out direction is front-facing (perp to DIN rail), so in a DIN-layout MCC the tech stands in front of the open door, sees the OS250D12P​ yellow handle, turns to OFF, pulls the three NH carriers (each ~150 mm long for NH2), and swaps the fuse link — no reaching deep into the panel. Touch-safe: when the OS250D12P​ is OFF and the carrier is pulled, the live parts (fuse-clips) are shrouded; when ON, the carrier is locked in and the IP20 body covers the clips.Bidirectional & Visual Status.​ The OS250D12P​ is bidirectional (line and load can be reversed) provided the panel designer is aware — some specs mandate “line top, load bottom” for consistency, but electrically the OS doesn’t care. Visual status: yellow handle body visible from aisle (switch present in MCC section), red knob = ON (visible through the small window even with door closed if door-coupling fitted), yellow knob = OFF. Combined with the padlock on OFF, this gives the maintenance crew three confirmations: (1) handle position, (2) padlock present, (3) DMM check at downstream端子 — ABB’s OS/OT family is designed around this “see, lock, verify” triad.

 

Application Field

The ABB OS250D12P​ (1SCA022726R8380) deploys wherever a 250 A / 690 V class fused isolation is needed between the upstream distribution and a load that justifies a dedicated fuse (rather than just an MCB or a non-fused disconnect). The flagship cluster is MCC main switches and feeder switches: a 400 V MCC feeding 132–200 kW motors (cement mill aux, mining conveyor, water pump station, paper-machine aux) typically uses 250 A feeder circuits — cable sized 185–240 mm² Cu, protected by NH2 250 A gG (distribution) or 200 A aM (motor), isolated by OS250D12P. The OS250D12P​ sits at the top of each feeder “bucket” or on the MCC vertical DIN rail, upstream of the contactor + O/L + soft-starter or VFD. On a 6-bucket MCC section, six OS250D12P​ units (one per bucket) plus one main OS400D12P​ or OS630​ at the section incomer is a standard build.Second: drive infeed isolation. Pairing with our earlier ABB drive models: an ACS800 MD chassis (690 V) or ACS880 MD chassis fed from a 250 A / 690 V branch would have an OS250D12P​ upstream on the 690 V distribution board, then cable to the drive’s main terminals. The OS250D12P​ gives the drive commissioning crew an LTI point: isolate the OS250D12P, padlock, work the drive control-section (NMPP-02 / NXPP-02C, NDCU-04 / AM12) with 24 V standby alive, then remove padlock, close OS250D12P, power-up DC-link. On marine vessels (thruster VFDs, crane hoist drives at 690 V), the OS250D12P​ 1SCA022726R8380 is often the feeder isolator on the 690 V switchboard feeding each VFD — DNV/ABS typed panels use ABB OS series because the handle, padlock, and fuse coordination are type-approvable.Third: UPS input/output and data-center PDU isolation. A 250 kVA UPS at 400 V (~360 A) oversized to 250 A feeder — the OS250D12P​ isolates the UPS input from the mains distro and the output to the critical PDU. Data-center MEP specs often mandate fused isolation (not just MCCB) for UPS paths because the fuse gives a more predictable let-through under short-circuit than some MCCBs — the OS250D12P​ + NH2 gG is a standard spec.Fourth: PV inverter AC isolation and energy-storage PCS AC isolation (commercial/industrial PV, 800 V DC solar → 690 V AC export — the AC side at 690 V uses 250 A class for ~175 kW AC per inverter, so OS250D12P​ per inverter string). Also building-retrofit distribution: old 400 V riser upgraded, new 250 A subboards fed from OS250D12P​ off the main switchboard.Retrofit context: ABB’s OS series is current/active (no LTB/PM500 notice that I’m aware — OS/OT are core LV products), so the OS250D12P​ 1SCA022726R8380 is buyable new-from-ABB. The only “retrofit” angle is plants that used the older OS250D… (pre-“12” variant) and want to confirm the 1SCA022726R8380 is the current article replacing whatever they had 10 years ago — ABB has kept OS250 form-factor stable, so a swap OS250-old → OS250D12P​ is typically form-fit-function, but verify pole count (3P vs 4P) and DIN/panel mount details against the old panel’s cutout.