Pan Assembly Busbar Design Guide: Current Class, Ways, Dimensions and Panel Fit

Design a pan assembly busbar from the panel single-line diagram and load schedule, not from a product photograph alone. Define the current class, W configuration, phase and pole allocation, outgoing-device terminal geometry, incoming connection, enclosure fit, and required assembly verification before releasing a model.

For the KASEEY range, the initial model choice has two axes: KP-125A or KP-250A, and one of nine published configurations from 12W to 60W. This creates 18 candidate references. The selected reference still has to be coordinated with the breakers, incoming device, conductors, enclosure, protection arrangement, and verification evidence for the finished assembly.

What a Pan Assembly Busbar Includes

A pan assembly busbar is an organized distribution interior for a panelboard or distribution board. In the supplied KASEEY product image, the visible system includes:

• a long insulated distribution body;

• repeated, color-coded phase/circuit identification positions;

• projecting outgoing connection tabs on both sides;

• an incoming connection area at one end;

• mounting and connection hardware;

• a removable insulating shroud over the incoming region.

These features make the product different from a loose pin or fork comb busbar. A comb busbar normally bridges a row of compatible modular devices; a pan assembly defines a larger panel interior with an incoming zone, repeated outgoing positions, support structure, identification, and enclosure-integration requirements. It is also different from a fabricated bare copper bar, which is designed around a separate support and connection scheme.

For general terminology and busbar types, use What Is a Busbar? Types, Ratings, Selection and Applications. This page stays focused on specifying the complete pan-assembly interface.

Convert the Panel Design into Nine Required Inputs

The design process is an input-to-specification chain. Do not select the current class or W configuration until the circuit architecture is stable enough to populate the following record.

This is intentionally broader than a model lookup. IEC TR 61439-0 describes the need for the specifier to define application and interface characteristics so an assembly manufacturer can produce the required assembly. The product reference is one output of that exchange, not a substitute for it.

Start with the Single-Line Diagram and Load Schedule

Map circuits to physical outgoing positions

List every outgoing protective device and record its pole count. A “12-way” requirement is ambiguous if the project has a mixture of single-pole and multi-pole devices, spare positions, or devices that occupy more than one module. Build a physical allocation drawing that shows each device, pole, terminal side, and reserved position.

The W suffix is a published KASEEY configuration identifier. Use it to retrieve the finished pan-assembly size, but confirm the actual circuit and pole allocation on the approved drawing. Do not assume that matching a numerical way count automatically proves that every proposed breaker arrangement fits.

Define phase sequence and load allocation

The supplied product visibly uses repeated colored B/Y/R labels. Treat those labels as an identification aid whose exact sequence and project meaning must be confirmed on the controlled drawing. The design record should show which outgoing position is assigned to each phase and how multi-pole devices span positions.

Load balancing is an assembly-design task. Use the project load schedule, demand assumptions, operating pattern, and applicable design method; do not infer balanced loading merely because the printed color sequence repeats evenly.

Freeze the outgoing-device interface

Record the exact breaker or protective-device family before approving the pan assembly. DIN mounting alone does not prove terminal compatibility. Check:

• device width and pole pitch;

• line/load terminal location;

• terminal opening and clamp method;

• required tab width, thickness, insertion depth, and orientation;

• device body and toggle position relative to the shroud or front cover;

• permitted combination of single- and multi-pole devices;

• any manufacturer-approved accessory or adapter requirement.

A metal tab entering the terminal is not enough. The receiving terminal must capture the intended contact area in the final mounted position.

Select the KASEEY Current Class and W Configuration

The KASEEY pan assembly busbar product page publishes two current classes. KP-125A uses a 2 × 5 mm connect size and 2 × 20 mm outline size; KP-250A uses 3 × 5 mm and 3 × 20 mm respectively. Each class is available in nine W configurations.

The dimensions below are the published finished busbar sizes in length × width × height. They are product lookup values, not enclosure-clearance allowances.

Use the class name as a candidate product family—not as proof that the complete panel has the same usable current rating under every condition. The final design still depends on the complete assembly, device ratings, conductor arrangement, ambient conditions, temperature-rise verification, short-circuit performance, and applicable design rules.

Coordinate the Incoming Connection

The incoming end brings together the supply conductor or incomer, connection block, metal connection pieces, mounting base, and insulating cover. Capture the following before approving a sample:

Do not copy torque values or conductor ranges from another pan-assembly family. If a required KASEEY value is absent from the public record, request the current controlled drawing or written technical confirmation.

Verify Enclosure Fit and Protection as a Complete Assembly

The published product length, width, and height do not include every installation allowance. Build an enclosure overlay or physical mock-up that includes the pan assembly, outgoing devices, incoming component, conductors, front cover, door, gland plates, neutral/earth bars where applicable, and adjacent equipment.

Check four zones:

1. Mounting zone: base holes, support surfaces, fastener access, rigidity, and alignment.

2. Connection zone: outgoing terminal engagement, incoming links, cable approach, and conductor bend space.

3. Protection zone: insulating shroud, front cover openings, barriers, and access to live parts under the intended operating/maintenance state.

4. Service zone: identification visibility, inspection access, device replacement path, and the ability to restore covers correctly.

Protective accessories must be selected as part of the same architecture. The separate guide to Protective Covers and Wiring Bridges in Panel Assemblies explains their role without treating them as automatic proof of an enclosure or assembly protection rating.

Manufacturer systems illustrate why integration must remain family-specific. Eaton describes pan assemblies intended for factory-built assemblies and distribution-board interiors, while Hager and ABB publish named board systems with their own mounting, incomer, way, and shrouding arrangements. Those examples support the integration method; their ratings and compatibility do not transfer to KASEEY products.

Keep Product Selection Separate from Assembly Verification

IEC 61439-1 provides general rules for low-voltage switchgear and controlgear assemblies when called up by the relevant assembly standard. IEC 61439-2 gives specific requirements for power switchgear and controlgear assemblies within its scope. The applicable part depends on the finished assembly and its intended market and use.

For a pan-assembly design, establish the verification plan before procurement release. Depending on the applicable framework and declared design, evidence may be needed for:

• current-carrying capability and temperature rise;

• short-circuit withstand or conditional short-circuit performance;

• dielectric and insulation-coordination requirements;

• clearances, creepage distances, and protection against electric shock;

• mechanical operation and device integration;

• enclosure protection and environmental conditions;

• markings, drawings, routine verification, and production records.

This article does not claim that every KP reference carries a particular certification or test result. Match each certificate, report, or declaration to the exact model, assembly construction, destination market, and document revision.

Release a Controlled RFQ and Sample

Use one record from first inquiry through repeat orders.

Approve a representative sample with the actual outgoing devices, incoming arrangement, and enclosure parts. Record tab engagement, device alignment, phase identification, cover fit, cable space, and drawing agreement. Any electrical or mechanical test must follow the applicable controlled procedure.

After approval, preserve the exact model, drawings, evidence revisions, sample photographs, approved device list, inspection record, and purchase-order description. This prevents a later order from being accepted because it has the same W suffix or looks similar.

Send the completed design-release record to sales@kaseey.com when evaluating the KASEEY pan assembly busbar range or a panel-specific requirement.

Technical References

• IEC TR 61439-0:2022 — Guidance to specifying assemblies

• IEC 61439-1:2020 — General rules

• IEC 61439-2:2020 — Power switchgear and controlgear assemblies

• Eaton Memshield 3 MCB pan assemblies

• Hager TP&N distribution-board systems

• ABB Protecta Power distribution-board system