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Laminated Busbar Standards and Certifications – What You Need to Know

07/06

2026

By A&JLINK Engineering Team · Last updated July 2026 · 8 min read
The short answer
The three IEC standards that matter most when a laminated busbar is specified — and the distinction that saves engineers from confusion.
  • ✓Why standards matter. They turn "electrical safety," "thermal life," and "system compatibility" into verifiable pass/fail criteria.
  • ✓The big three. IEC 60664-1 (insulation coordination), IEC 60216 (thermal endurance), and IEC 61439-1 (low-voltage assemblies).
  • ✓The key distinction. Standards define the safety floor; low inductance and high current are design goals, not standard requirements.
A laminated busbar is judged on two things that are easy to confuse. One is performance — how low the inductance goes, how much current it carries, how tightly it packages. The other is compliance — whether it meets the standards that make it safe and predictable over a long service life. This article is about the second one: the busbar standards and certifications that actually matter.
Three IEC standards do most of the work when a laminated busbar is specified. IEC 60664-1 governs insulation coordination, IEC 60216 governs the thermal endurance of the insulating film, and IEC 61439-1 governs the switchgear and controlgear assemblies these busbars live inside. Each answers a different question, and each is routinely cited — or, just as often, cited wrong.
Scope: this article explains what each of these three IEC standards covers, how it applies to a laminated busbar, and how to reference it correctly in a specification. It does not cover the performance side of busbar design — for that, see our laminated busbar selection guide.
A laminated busbar is the backbone of low-inductance power distribution, and the standards below are what keep that backbone safe and predictable.

1. Why Standards Matter for Laminated Busbars

A standard is not a decoration on a datasheet. It converts three abstract requirements into measurable criteria. Electrical safety becomes a clearance and creepage distance. Thermal life becomes a temperature index. System compatibility becomes a type-test result.
The three IEC standards covered here map cleanly onto those three concerns. IEC 60664-1 governs how much insulation is enough. IEC 60216 governs how long that insulation will last at temperature. IEC 61439-1 governs how the busbar behaves as part of a complete assembly under fault and thermal stress.
There is a distinction worth stating up front, because it is the most common source of confusion. These standards define the safety floor — the minimum a busbar must meet to be safe and predictable. They do not define your busbar's headline performance. A low-inductance design is not a requirement of any IEC standard; it is a design objective you set because your application demands it. Standards and performance are two separate axes, and a good specification works both.

2. IEC 60664-1 — Insulation Coordination

IEC 60664-1 is the horizontal standard for insulation coordination in low-voltage equipment. Its precise scope matters: it applies to equipment rated up to AC 1000 V or DC 1500 V, at frequencies up to 30 kHz.
The standard sizes two distances that fail in different ways. Clearance is the shortest distance through air between two conductors, set by the impulse voltage the insulation must survive. Creepage is the shortest path along the surface of the insulation, set by the working voltage together with the pollution degree and the material's tracking resistance (its CTI). A laminated busbar has to get both right: the thin insulating film between layers provides the solid insulation, and the edge geometry around terminals and mounting points provides the clearance and creepage.
Three inputs drive the design: the overvoltage category, the pollution degree (1 through 4), and the material group of the insulating film. For a busbar, the pollution degree is often the one that surprises — a part specified for a clean indoor enclosure can fail creepage if it ends up in a contaminated or condensing environment.
One boundary is worth being precise about. IEC 60664-1 covers the low-voltage segment, so an 800 V EV inverter or an 800 V HVDC AI data-center busbar sits comfortably inside its scope. A grid busbar rated at 6.5 kV does not — it lies beyond the standard's low-voltage limit and needs a different insulation-coordination basis. For the coating and film selection that follows from this standard, see our guide on epoxy versus powder-coated busbars.

3. IEC 60216 — Thermal Endurance of Insulating Materials

IEC 60216 is about long-term thermal aging, not short-term heat resistance. The central concept is the temperature index (TI): the temperature at which a material reaches a defined end point — typically half its initial dielectric strength or mechanical strength — after 20,000 hours. Its companion is the halving interval (HIC), the temperature step that cuts the time-to-end-point in half. The HIC is measured per material and commonly lands between 8 and 12 K; it is not a fixed "10 degrees halves the life" rule, which is a rough approximation, not the standard's actual method.
For a laminated busbar, IEC 60216 is what tells you which insulating film belongs in the stack. The common films map to different thermal classes: PET sits in the 105–130 class, PU in a similar band, NOMEX around 220, and polyimide (PI/Kapton) in the 200–220 class. The choice follows the hottest point the busbar will actually reach across its duty cycle — not the nominal ambient.
The practical rule is to take the film's TI, subtract real headroom, and design against the hottest spot, not the housing temperature. This is the same thermal logic that sits behind our ANSYS simulation work; see our guide on laminated busbar thermal simulation for how it is applied.

4. IEC 61439-1 — Switchgear and Controlgear Assemblies

IEC 61439-1 governs low-voltage switchgear and controlgear assemblies. It is important to get the relationship right: the busbar itself is not the direct object of this standard. The busbar is the busbar system inside an assembly, and it is covered by 61439-1 through the type tests applied to that assembly.
Two of those tests matter most for a busbar. The temperature-rise test verifies that the assembly, busbar included, stays within its thermal limits at rated current. The short-circuit withstand test verifies the busbar's rated short-time withstand current (Icw) and peak withstand current (Ipk) — the ability to survive a fault without mechanical or thermal damage until the protective device clears it.
For an engineer specifying a busbar, the practical meaning is this: the busbar's short-circuit and temperature-rise performance is not an isolated number. It is verified in the context of the assembly it will live in, and the specification should state the required Icw and the assembly standard rather than leaving the busbar to be judged in isolation.

5. How to Reference These Standards in Your Specification

The most common way standards get "cited" is also the most useless: writing "compliant with IEC" with no standard number and no clause. A useful specification names the standard, the part, and the relevant clause, and states the inputs the supplier needs to verify against it.
Three errors recur. The first is citing a standard without a number — which tells the supplier nothing. The second is misapplying the low-voltage boundary of IEC 60664-1 to a busbar that is actually outside it. The third is treating low inductance as a standard requirement — it is a design goal, and writing it as if a standard enforces it invites confusion.
A clean reference looks like this: for the insulation, "insulation coordination per IEC 60664-1, pollution degree 2, overvoltage category III"; for the film, "insulating film with a temperature index per IEC 60216 of at least 130"; for the system, "busbar rated for short-time withstand Icw per IEC 61439-1." Each gives the supplier a verifiable target.
Finally, a standard is only as good as the evidence behind it. Ask the supplier how compliance is demonstrated — which tests, on which samples, with which results. For what to look for in that evidence, see our guide on quality control in laminated busbar manufacturing.

Summary

Three IEC standards do the heavy lifting when a laminated busbar is specified. IEC 60664-1 sets the insulation-coordination floor for low-voltage designs. IEC 60216 sets the thermal life of the insulating film. IEC 61439-1 verifies the busbar as part of a complete assembly. Together they are the safety, thermal, and system pillars of a sound specification.
And keep the distinction clear: standards define the safety floor, while your busbar's headline performance — low inductance, high current — is a design goal you set for your application. Both belong in the specification, but they are not the same thing. Name the right standard, state the right clause, and ask for the evidence — that is how a laminated busbar gets specified correctly the first time.
Specify Your Busbar Against the Right Standards
Send us your current, voltage, and duty-cycle requirements — our engineers will review feasibility and come back with design recommendations.
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References & Standards

  1. IEC 60664-1 — Insulation coordination for equipment within low-voltage supply systems. International Electrotechnical Commission. webstore.iec.ch
  2. IEC 60216 — Electrical insulating materials – Thermal endurance properties. International Electrotechnical Commission. webstore.iec.ch
  3. IEC 61439-1 — Low-voltage switchgear and controlgear assemblies. International Electrotechnical Commission. webstore.iec.ch

Prev: Future Trends in Laminated Busbar Technology – SiC, GaN, and Beyond

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