2020 NACE Paper

Can Anodes Interfere When They Are Mounted On Electrically Separate Structures?

By John Baynham and Tim Froome

When structures can be electrically isolated from one another, a sometimes-used approach for sacrificial anode cathodic protection design is to treat each structure independently of the others.

 This implies an assumption that interference cannot take place if structures are not electrically connected, and this might seem reasonable since recommended practices do not readily address interaction between the electric fields of anodes where one cathode ‘group’ and its associated anode arrangement is electrically isolated from  a second ‘group’.

Trends towards denser ‘packaging’ of structures, and additional complicating factors such as requirements for protective covers, mean that if interference effects do occur, they could result in significant damage.

This paper therefore uses simulation to investigate the likelihood of interference between multiple electrically isolated structures. The paper aims to identify whether interference can occur, and then, explores the types of situations where interference is likely, the type of effects which might be observed, and the possible severity of any such interference effects.