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1.5 Unit Withdrawable Drawer - up to 250A, for Larger Starters and Soft Starters

1.5 Unit Withdrawable Drawer - up to 250A, for Larger Starters and Soft Starters

1.5 unit withdrawable drawer to 250A for GCK, GCS and MNS. Extra depth for soft starters and larger starters. Factory wired and tested.

Overview
Applications
Technical Data
Services
Quality Control
Recommended Products

1.5 unit exists because of a practical problem: a soft starter, a larger star-delta arrangement or a 250A feeder physically does not fit inside a 1 unit drawer with correct clearances and serviceable wiring, but a 2 unit drawer wastes half the space. The intermediate size is what keeps a motor control centre compact without cramming components.

DO NOT FORCE COMPONENTS INTO A SMALLER DRAWER
This is one of the most common mistakes we see in locally built boards, and it is expensive twice over. Cramming a soft starter into a 1 unit shell leaves no clearance for heat dissipation, so the device runs hot and derates in a switchroom that is already at 50 C. It leaves no room to work, so field maintenance is slow and terminations get damaged. And it compromises clearance and creepage distances, which is exactly what an inspector checks. Specify the correct module size and none of these problems exist.

THERMAL HEADROOM IS THE REAL ARGUMENT
Soft starters and larger contactors dissipate real heat. In a Gulf or African switchroom already running well above the IEC +40 C reference ambient, the difference between a properly sized drawer and a crammed one is the difference between a device that delivers its nameplate rating and one that trips on a hot afternoon. The extra half-module costs very little at build time and eliminates a class of commissioning problems.

FACTORY BUILT AND TESTED
Assembled, wired, labelled and individually tested against the feeder schedule, with device brand to your specification and its own routine test certificate. Or supplied as a CKD kit with shell, isolating contacts, racking mechanism, interlock, handle, secondary plug, pre-cut modular harness, assembly drawing and torque sheet.

INTERCHANGEABLE ACROSS BATCHES
Module dimensions held to the same drawing revision, so a replacement unit years later still fits. The 1.5 unit shares the same isolating system, three-position mechanism and interlock scheme as the rest of the range - one mechanism to train your team on, one set of spares to hold.

Typical Applications

PRIMARY APPLICATIONS
- Soft starter feeders in motor control centres - the most common use of this size.
- Motor starters from approximately 45 kW to 90 kW.
- Distribution feeders up to 250A in withdrawable boards.
- Star-delta starters where the contactor set and timer will not fit a 1 unit shell.
- Large pump, fan, compressor and crusher drives.
- Cement mill auxiliaries, mining conveyors and crushers, water pumping stations.
- Chiller and large air handling plant in building services.
- Desalination high-pressure pump feeders.
- Sugar, paper and steel plant drive sections.

TYPICAL CONFIGURATIONS
Soft starter with bypass contactor, MCCB and electronic motor protection relay; star-delta starter with three contactors and timer; heavy direct-on-line starter; 250A distribution feeder with metering.

WHY THE SIZE IS CHOSEN
Because the components need the space - for clearance, for heat, and for a technician's hands. It is a straightforward engineering decision that a good panel builder makes at design stage and a poor one discovers during commissioning.

REGIONAL FIT
- Middle East: desalination, petrochemical and district cooling plants use soft starters extensively on large pump sets. High ambient makes the thermal headroom of the larger module genuinely necessary, not optional.
- Africa: mining and cement plant conveyors, crushers and mill auxiliaries. Soft starters reduce mechanical shock on long conveyors, which matters where mechanical spares are slow to source.
- Russia and CIS: 380V/220V, EAC under TR CU 004/2011 and TR CU 020/2011.
- Eastern Europe: 400V, CE under LVD and EMC to EN 61439-2.

NOT SUITABLE FOR
Variable frequency drives above small ratings, which need the ventilation and depth of a 2 unit drawer or a dedicated cubicle. Fixed-type boards such as GGD, XL-21 and JXF.

Technical Data

TECHNICAL DATA - 1.5 Unit Withdrawable Functional Unit

Compliance: IEC 61439-1, IEC 61439-2, IEC 60947-2, GB 7251.1

Category	Item	Parameter Details
ELECTRICAL RATINGS	Rated operational voltage (Ue)	400 V / 415 V AC (380 V available)
	Rated insulation voltage (Ui)	1000 V
	Rated impulse withstand voltage (Uimp)	8 kV
	Rated frequency	50 Hz / 60 Hz
	Rated current of unit	up to 250 A
	Rated short-time withstand of the assembly (Icw)	up to 80 kA for 1 s
	Rated conditional short-circuit current	determined by the fitted device
	Control voltage	230 V AC, 110 V AC, 24 V DC
MODULE GEOMETRY	Module size	full module width, one and a half unit height
	Module height	1.5 unit
	Units per standard section	up to 12 units of this size in a standard 1000 mm wide section, arrangement dependent
	Interchangeability	dimensionally identical across production batches and years
ISOLATING SYSTEM	Working Positions	Connect / Test / Disconnect, each positively latched with indication
	Primary contacts	silver-plated copper, spring-loaded, self-aligning
	Secondary contacts	silver-plated multi-pin plug, engages in Test position
	Earth contact	engages before and breaks after the power contacts
	Mechanical endurance	100,000 operating cycles
	Racking mode	manual handle racking, tool-free
INTERLOCKS	Interlock Functions	1. Drawer cannot be racked while the device is closed 2. Device cannot be closed between defined positions 3. Door cannot be opened with the device closed (defeatable by tool for authorised access) 4. Padlocking provision in the Disconnect position
FEEDER DEVICE	Applicable MCCB / Starter	MCCB frame up to 250 A, or starter up to approximately 90 kW
	Feeder types	soft starter with bypass, star-delta starter, heavy direct-on-line starter, distribution feeder
	Motor protection	electronic motor protection relay with earth fault, thermistor input and fieldbus communication
CONSTRUCTION	Shell Material	aluminium-zinc coated steel, powder coated
	Internal separation	Form 3b / Form 4b per IEC 61439-2 when installed
	Protection degree	IP30 to IP54 depending on cabinet configuration
	Wiring	pre-cut modular harness, ferruled and labelled, reducing on-site assembly labour by approximately 30% versus wire-by-wire termination
	Terminals	front accessible, sized for the feeder cable range
TESTING - EVERY UNIT	Factory Test Items	Dielectric withstand 1 minute at rated test voltage; insulation resistance recorded; three-position operation and interlock function verified; contact alignment and engagement gauged; functional test of the feeder logic
SERVICE CONDITIONS	Ambient temperature	-5 ℃ to +40 ℃ per IEC; verified to +55 ℃ with derating
	Relative humidity	50% at +40 ℃, up to 90% at +20 ℃
	Altitude	up to 2000 m

NOTE
Choose this size whenever a soft starter, a full star-delta contactor set or a 250A feeder is specified. Forcing those components into a 1 unit shell compromises clearance, heat dissipation and maintainability.

Services

SUPPLIED READY TO INSTALL - THE HARD PART IS ALREADY DONE

A drawer is not a box with a breaker in it. Contact alignment, three-position interlock geometry and secondary plug engagement are the parts of a withdrawable board that local workshops get wrong, and a misaligned drawer is what turns into a burned contact two years later. We supply the units assembled, wired and tested, so your workshop is building a cabinet - not debugging a mechanism.

1. FUNCTIONAL UNITS BUILT TO YOUR SCHEDULE
Send us the feeder schedule and we build the drawers to it: distribution, direct-on-line, star-delta, soft starter, VFD, reversing. Device brand to your specification. Each unit is delivered wired to terminals, labelled and individually tested.

2. INTERCHANGEABILITY GUARANTEED ACROSS BATCHES
Standard module dimensions are held to the same drawing revision year after year. A 1-unit drawer ordered today fits a cabinet you built three years ago. This is the single reason consultants specify a standardised system, and it is where a proprietary in-house drawer design costs the client later.

3. CKD DRAWER KITS FOR LOCAL ASSEMBLY
If you would rather assemble in-house, we supply the drawer as a kit: shell, isolating contacts, racking mechanism, interlock, handle, secondary plug and wiring harness, with the assembly drawing and a torque and gauge sheet. The pre-cut modular wiring harness alone removes about 30% of on-site assembly labour compared with cutting and crimping wire by wire.

4. TRAINING ON THE MECHANISM
Alignment, contact pressure check, three-position verification, interlock function test and racking force check - taught on your own bench with your own units, on site or by video session.

5. SPARE DRAWERS AND SPARES STRATEGY
Quote the spare drawer set with the main order. A hot spare drawer is what lets a plant restore a feeder in minutes instead of hours, and on EPC projects it is often the reason a withdrawable board was specified in the first place. We keep the design available so spares remain buyable for the life of the installation.

6. DOCUMENTATION FOR YOUR SUBMITTAL
Routine test certificate per unit, device certificates, wiring diagram, drawer schedule and part list. Formatted so it drops straight into your IEC 61439 verification file.

7. AFTER-SALES
24-hour technical response, 12 months from commissioning or 18 months from shipment, spare contact and interlock parts held to the same revision.

8. COMMERCIAL TERMS
FOB, CFR, CIF, DDP, Ex-Works. Mixed loading with cabinets and components. Trade Assurance, T/T, L/C. Sample units accepted before volume.

Quality Control

QUALITY CONTROL - EVERY DRAWER TESTED AS A UNIT

A withdrawable board fails at the interface, not in the middle of a component. Contact pressure, alignment and interlock geometry decide whether the drawer is still healthy after a thousand operations, and none of that is visible after the door is closed. Each unit is therefore tested as a complete assembly before it leaves the line.

DIMENSIONAL AND MECHANICAL CHECKS - 100%
1. Shell dimensions and squareness against the module drawing, so interchangeability with earlier batches is real and not assumed.
2. Isolating contact alignment and engagement depth verified with a gauge; contact pressure measured against specification.
3. Silver plating thickness on primary and secondary contacts checked on batch samples.
4. Three-position operation - Connect, Test, Disconnect - each position confirmed to latch positively with correct indication.
5. Interlock function - the drawer cannot be racked with the device closed, and the device cannot be closed between defined positions. Tested in both directions.
6. Racking operating force measured and recorded; a stiff mechanism is rejected, not adjusted at the customer's site.
7. Earth contact sequence verified - the earth contact must make before and break after the power contacts.
8. Mechanical endurance qualified to 100,000 cycles on type-test samples.

ELECTRICAL CHECKS - 100%
9. Wiring verified against the unit schematic; ferrules, terminal tightness and labelling checked.
10. Secondary plug pin-out verified circuit by circuit.
11. Dielectric withstand test at the rated test voltage for one minute, and insulation resistance measured and recorded.
12. Functional test of the feeder logic - starter sequence, protection relay settings, indication and, where fitted, communication.

WHAT YOU RECEIVE
Individual routine test certificate carrying the unit serial number, drawer schedule, wiring diagram, device certificates, and the type-test evidence for the drawer system to support your IEC 61439 verification file.

TRACEABILITY AND SPARES
Every unit is serialised against its drawing revision. When you order a replacement in five years, the drawer that arrives is the drawer that fits. Sample units are supplied for fit-up trials before volume production, and third-party inspection is accepted on request.