Board Types & Classifications

Single-phase consumer units, three-phase TPN boards and busbar architecture explained

Open sizing tools ↓Enquire about this application ↗

Board Types & Classifications

Classify a board by its phase arrangement, incoming and outgoing circuits, enclosure, internal separation and verified electrical performance. The reference images below distinguish a single-phase consumer unit, a wall-mounted distribution panelboard and a cubicle switchboard lineup.

SPN and TPN describe the supply arrangement. Horizontal or vertical chassis describes the physical device layout. Type A and Type B board terminology must be interpreted using the manufacturer’s range documentation; it is not a universal current rating or the same as an MCB trip curve or RCD type.

Board Architecture In Practice

Tier 3 · Final circuitsPictured: Schneider Electric Easy9 EZ9EFS12CMCU consumer unit.

Single-Phase Metal Consumer Units

The Schneider Electric Easy9 EZ9EFS12CMCU is a 12-way single-phase metal consumer-unit reference for final circuits. MCB, RCD and RCBO selection, loading and enclosure configuration must be confirmed for the actual board.

ConfigurationSingle phase + neutral

ReferenceEasy9 · 12-way

ProtectionSelect per circuit

Tier 2 · Floor or zonePictured: NHP Concept Plus wall-mounted distribution panelboard family.

Three-Phase TPN Distribution Panelboards

The NHP Concept Plus family shows a wall-mounted panelboard with its accessory enclosure, suitable as a sub-distribution reference. This Australian AS/NZS 61439-3 range has isolator incomers up to 250 A or MCCB incomers up to 200 A; it is not a Form 4 main-switchboard lineup.

Isolator incomerUp to 250 A

MCCB incomerUp to 200 A

ReferenceNHP Concept Plus

Tier 1 · Primary intakePictured: ABB MNS Digital low-voltage switchgear and motor control lineup.

Cubicle Switchboard Lineups & Separation

ABB MNS Digital is pictured as a primary-intake and motor-control lineup reference. NPE project assemblies are specified from the load schedule, prospective fault current and operating conditions; the photograph does not establish a particular current, fault or separation rating.

RolePrimary intake

AssemblyIEC 61439-1 / -2 scope

RatingsProject-specific verification

Explore Cubicle Switchboard Lineups & Separation

Single-Phase vs Three-Phase Boards

Selection item	Single-phase final board	Three-phase distribution board
Supply	230 / 240 V AC, phase + neutral	400 / 415 V AC, three phases + neutral, 50 Hz
Pictured reference	Schneider Electric Easy9 12-way consumer unit	NHP Concept Plus Australian panelboard family
Incomer	Select the exact consumer-unit configuration	Pictured NHP family: isolator up to 250 A or MCCB up to 200 A
Outgoing protection	MCB / RCBO circuits as specified	Single- or multipole devices supported by the chosen chassis
Fault rating	Match the actual assembly and device ratings to the fault study	Confirm assembly withstand and device Icu / Ics at system voltage
Standard scope	IEC 61439-3 where applicable to the actual assembly	IEC 61439-2 or -3 according to assembly scope; pictured family AS/NZS 61439-3

Type A vs Type B Busbar Orientation

Layout term	Meaning	Selection limit
SPN / TPN	Phase and neutral arrangement	Confirm actual circuit and supply requirements.
Horizontal / vertical chassis	Physical layout of busbars and outgoing devices	Verify compatible device families; orientation alone does not establish current or fault rating.
Type A / Type B board	Range-specific distribution-board terminology	Use the board manufacturer’s definition; do not confuse it with MCB trip curves or RCD types.

Forms of Separation (IEC 61439-2)

Form · IEC 61439-2	Separation principle	Engineering note
Form 1	No internal separation	Select against project access and operation needs.
Form 2	Busbars separated from functional units	The a/b subdivision defines terminal separation from busbars.
Form 3	Busbars separated from units; units separated from one another	Specify the terminal arrangement and required a/b subdivision.
Form 4	Additional separation of terminals associated with each functional unit	Specify the exact arrangement. Separation does not permit live maintenance.

Key Features Across All Board Types

Type-tested / design-verified assemblies to IEC 61439 with verification documents confirmed for the proposed assembly
Frames from 2.0–2.5 mm sheet steel; doors and covers from 1.2–1.6 mm sheet steel
HDHC tin-plated copper busbars with no-drill clamp connections
Standard IP43 ingress protection; IP54 and IP65 available on request
Epoxy powder-coated light grey RAL 7035 at 50–75 micron thickness
Tested for operation at 50 °C ambient temperature
Front or rear cabling access with removable gland plates and barriers
Modular frame widths of 400, 600, 800 and 1000 mm; depths of 800 or 1000 mm

Typical Applications

Residential estates and apartments Commercial offices and retail Factories and process plant Hospitals and healthcare Data centres and telecom Schools and universities Water and infrastructure Hotels and hospitality

These terms depend on the board manufacturer and range. Confirm phase arrangement, device compatibility, chassis layout and verified ratings from the specific catalogue. Do not infer heavy-duty performance from busbar orientation or confuse board terminology with an MCB trip curve or RCD type.

Select the form from the operating, access and project requirements, then confirm the exact compartment and terminal arrangement under IEC 61439-2. Form 2 is not a universal minimum for every sub-board. Forms 3 and 4 do not authorise live maintenance; apply the approved isolation and safe-working procedure.

Only where the chosen manufacturer’s chassis, busbar, device compatibility and assembly verification support that combination. Agree outgoing circuits and phase allocation before selecting the board.

Select the enclosure rating from rain, dust, washdown, access and installation conditions, then confirm cable entries and ventilation preserve the required protection. The IP rating alone does not establish suitability for every outdoor environment.

Need Help Selecting the Right Board Type?

Send your single-line diagram and load schedule and we will recommend the correct board configuration for your project.

Discuss Your Requirement

Explore your requirements.

Try the tools relevant to board types & classifications, compare scenarios, then send the inputs to our team.

Enable JavaScript for live calculations, or ask our engineering team.

Conceptual engineering scenes illustrate applications. Manufacturer reference photos are identified separately. Confirm exact models, dimensions and ratings before ordering.