Bimetallic corrosion prevention in connections
What it looks like
Direct contact between incompatible metals, such as steel and copper, without isolation, can lead to accelerated corrosion of the more anodic metal.
Why it happens
When different metals are joined, precautions must be taken to prevent bimetallic (galvanic) corrosion, which can occur if the metals have significantly different electrochemical potentials. This can be achieved by using compatible metals or by isolating them from each other with an inert material.
What it costs if it is missed
When different metals are joined, precautions must be taken to prevent bimetallic (galvanic) corrosion, which can occur if the metals have significantly different electrochemical potentials. This can be achieved by using compatible metals or by isolating them from each other with an inert material.
How to inspect for it
Check that connections between dissimilar metals are either inherently compatible or feature an appropriate isolation layer to prevent corrosion.
How to prevent it
When different metals are joined, precautions must be taken to prevent bimetallic (galvanic) corrosion, which can occur if the metals have significantly different electrochemical potentials. This can be achieved by using compatible metals or by isolating them from each other with an inert material.
Basis in regulation
Last updated 23 August 2026. This is our editorial summary of publicly available regulation and site practice, not building control approval or a warranty determination.