Laminated Busbar Design Guide

A laminated busbar is a multi-layer conductor assembly. Flat copper conductors are separated by thin dielectric films and bonded together under heat and pressure into a single insulated part. Terminals — threaded studs, blade tabs or welded lugs — are mounted before lamination or welded on afterwards. The finished assembly installs as one piece.

The idea is simple: instead of routing individual cables or assembling flat buswork on the line, you buy one insulated part with every connection pre-positioned.

Conductors — C11000 copper sheet, laser-cut or punched to profile, tin plated for corrosion resistance and joint solderability.

Dielectric films — PET, Nomex or epoxy-based (DLF) films, sized to cover the conductor with proper creepage margins.

Stack-up — conductors and films layered in the designed order; adjacent layers are usually offset so terminals stay accessible.

Lamination — heat and pressure bond the stack; the recipe holds dielectric thickness within tolerance.

Edge sealing — cut edges are sealed so dielectric layers cannot creep or track under voltage.

Terminals — studs and tabs welded or fastened in position.

Trim and inspect — final CNC trimming and dimensional verification.

The dielectric does three jobs at once: it insulates between layers, it bonds the stack, and it sets the thermal class of the assembly. The common choices:

Material	Strengths	Watch-outs
PET (Mylar)	Low cost, good dielectric strength, thin for compact stacks	Lower continuous temperature limit than alternatives
Nomex	High temperature rating, excellent thermal stability	Higher cost, thicker per layer
Epoxy (DLF)	Rigid, self-extinguishing options, good mechanical strength	Less flexible stack-up, material handling during layup

Our default selection starts from your voltage class and operating temperature, then balances layer count against dielectric thickness to hit your creepage and clearance requirements.

Two limits govern a busbar: temperature rise (resistive heating) and insulation class (the dielectric sets the maximum continuous temperature). For copper at a 30 °C rise, the common industry reference points are:

Copper cross-section	Approx. DC current (30 °C rise)
10 × 3 mm	~150 A
20 × 3 mm	~250 A
30 × 5 mm	~450 A
40 × 5 mm	~550 A
50 × 5 mm	~650 A
60 × 6 mm	~800 A
80 × 6 mm	~1000 A
100 × 6 mm	~1150 A

See the full chart with derating factors in our Busbar Ampacity Chart.