Almost every LV switchgear panel manufacturer in Pakistan says its panels follow IEC 61439. Few buyers know what that claim should actually mean or how to check it. This guide explains the standard in plain terms and gives you a list of questions and documents to request before you order.
What Is IEC 61439?
IEC 61439 is the international standard for low voltage switchgear and controlgear assemblies. It means the complete panel, not just the breakers inside it. It lays down the definitions, construction requirements, technical characteristics and verification requirements for these assemblies.
The series is split into parts:
- IEC 61439-1: general rules that apply to all assemblies
- IEC 61439-2: power switchgear and controlgear assemblies, which covers MDBs, PCC panels, and MCC panels
- IEC 61439-3: distribution boards operated by ordinary persons (DBO)
The general-rules part is now in its third edition (published 2020), which replaced the 2011 edition. If a quotation still references the older edition or the older IEC 60439 standard, ask why.
“Type-Tested” vs “Design Verified”: Why the Language Changed
Older panels were described as “type-tested” or “partially type-tested” assemblies. IEC 61439 replaced that language with design verification and the shift matters when you read a supplier’s claims.
Under IEC 61439, a panel’s design must be verified against the standard’s requirements. The standard allows three verification methods:
- Testing of the design
- Calculation or measurement against the standard’s rules
- Design rules, comparing against an already-verified reference design
Characteristics that must be verified include temperature rise, dielectric properties, short-circuit withstand strength and protective circuit integrity. In addition, every individual panel that leaves the factory must pass routine verification (production checks) before delivery.
Why this matters to you: “Built to IEC 61439” can mean very different things. A supplier who has verified the design and can show the evidence is in a different category from one who simply used the standard as a general reference. Always ask which one applies.
Key Ratings to Look For on Any LV Panel Specification
When reviewing a quotation for an LV switchgear panel, these are the characteristics that define what the panel can safely do:
| Rating | What it tells you |
|---|---|
| Rated current (InA) | The maximum current the assembly can carry continuously |
| Rated short-time withstand current (Icw) | How much fault current the busbars can withstand for a set time |
| Rated peak withstand current (Ipk) | The peak fault current the assembly can survive |
| Rated diversity factor (RDF) | How much load can run simultaneously without overheating |
| Form of internal separation | Form-1 to Form-4b, i.e. how well sections are isolated from each other |
| IP rating | Protection against dust and water ingress |
Comparing two quotations without these figures is comparing price only, not safety.
Forms of Separation, in One Paragraph
IEC 61439 describes how busbars, functional units]lp and terminals are separated inside a panel using Form-1 (no internal separation) up to Form-4b (separate compartments and separate terminals per functional unit). Higher forms cost more but allow maintenance on one section while others stay live, and limit how far a fault spreads. For plants where downtime is expensive, such as textile mills, cement plants, and sugar mills, higher forms are often worth specifying. We cover this in detail in our guide to Form-1 to Form-4b.
What to Ask Your Panel Manufacturer: A Practical Checklist
Before you place an order, ask for:
- The edition and parts of IEC 61439 the panel is designed to (for example IEC 61439-1 & 2)
- Design verification evidence for the assembly or its reference design (test reports, calculations, or design-rule records)
- Routine verification (factory test) records for the specific panel you are buying, issued as part of factory acceptance testing
- The rated values: InA, Icw, Ipk, RDF, and IP rating, written into the quotation
- The form of separation specified for each section
- Breaker and component brands fitted, with their own certificates where applicable
- Who the “original manufacturer” is. Under the standard, the party that carries out the design carries responsibility for it, even if another party assembles the panel
A manufacturer that answers these precisely and promptly is demonstrating the kind of discipline you want inside your panel as well.
How FICO Engineering Approaches It
FICO Engineering manufactures LV switchgear in Gujranwala designed in accordance with IEC 61439-1 & 2, in modular configurations from 630A to 6300A, with Form-1 to Form-4b segregation for indoor and outdoor installation. Our MDB, PDB, MCC, ATS, and PFI panels are backed by in-house engineering, factory acceptance testing, and commissioning support.
We recommend every buyer use the checklist above with us and with any other supplier they evaluate.
