Tel +86 136 4542 9121 WhatsApp +1 519 253 9195 busbar@shanyo.com
Mon–Fri 9:00–18:00 · CST (UTC+8) · Shandong, China
Resource · Ampacity Chart

Copper Busbar Ampacity Chart

Copper busbar current ratings by cross-section, plus the derating factors that decide whether those numbers survive in your enclosure.

Copper Busbar Ampacity — DC and 50/60 Hz AC

Values below are the standard industry reference for copper bars (C11000) at a 30 °C rise above a 40 °C ambient, mounted flat in free air:

Cross-section (mm)Area (mm²)DC current (A)AC 60 Hz (A)
10 × 330~150~150
15 × 345~200~200
20 × 360~250~250
25 × 375~300~295
30 × 5150~450~440
40 × 5200~550~535
50 × 5250~650~630
60 × 6360~800~770
80 × 6480~1000~960
100 × 6600~1150~1100

The table above is a starting point. In a real assembly, apply the derating factors below.

Derating: Where the Real Number Comes From

FactorEffectTypical derate
Ambient temperatureHigher ambient raises conductor temperature−1% per °C above 40 °C
Bundled barsAdjacent conductors heat each other−10 to −20% depending on spacing
Enclosed / still airReduced convection−10 to −25%
AltitudeThinner air cools less effectively−1% per 200 m above 1000 m
AC frequencySkin and proximity effect push current to surfacesMaterial above ~1 kHz; consult us
Pulsed currentThermal mass absorbs short pulsesCan allow higher peaks than continuous

Laminated Stacks vs. Single Bars

A laminated busbar is not a single thick bar — it is several thinner conductors in parallel. Total cross-section sets the resistive heating, but current sharing between layers depends on terminal placement and connection symmetry. Uneven sharing overloads one layer while another runs cool. This is why terminal layout is reviewed during our DFM stage rather than left to chance.

How We Use This Chart

  • Start with your continuous current and voltage class.
  • Apply the derating factors for your actual mounting and ambient.
  • Select conductor cross-section and layer count with margin.
  • Confirm the thermal class of the dielectric against the resulting temperature.
Send us your current profile and installation conditions — we will size the busbar and document the calculation with your quotation.

Try the Sizing Tool

≈ 450 ASchematic estimate — final sizing reviewed per drawing at DFM.
13+Years since 2012
1–6+Conductor layers
~1000 ACurrent rating
1 dayTechnical response
FAQ

Common questions

How many conductor layers can you build?
We build custom stack-ups from 1 to 6+ layers. Layer count, terminal layout and mounting configuration are all defined by your drawing and reviewed at DFM before tooling.
What current ratings can SHANYUAN busbars handle?
Rating is designed per application up to roughly 1000 A, sized against continuous and peak current with thermal margin — see our ampacity chart for the starting reference points.
What information do you need to quote a laminated busbar?
A drawing (PDF or DXF) or a photo of an existing sample, the required current rating and voltage class, number of conductor layers, terminal types, estimated annual quantity, and the application. With a complete specification, our engineering team typically responds within one business day.

We build busbars — factory direct.

Send the current profile, voltage class and installation conditions — we will size the busbar and document the calculation with your quotation.

Send Your SpecsWhatsApp

Need this checked against your design?

Send the current profile, voltage class and installation conditions — we will size the busbar and document the calculation.

Send Your Specs