Galvanic Protection

[tomdes]

When grounding a Aluminum product to a Carbon Steel deck offshore what is best steps to take to reduce the galvanic charge into the Aluminum product.

 

[rmw]

Electrically isolate it from the CS.

rmw

 

[tomdes]

The only problem is I have to ground the aluminum to steel deck, not sure how to completely isolate electric currents between the two metals, need some to block galvanic currents, still allowing a ground for electrical current.

 

[tomdes]

Is there any way to stop dc current that cause galvanic corrosion, but still allows Ac current for grounding two dissimilar metals.

 

[ScottyUK]

Interface pads are available to avoid dissimilar metal problems when jointing copper conductors to aluminium condcutors. These might be an option, depending no how big the 'product' is.

A quick Google found these:

http://www.insulcon.com/page/products/Transition_Joints.htm

 

[VEBill]

Electrically isolate the product's aluminum chassis from the steel vessel, and then ground it with an easily replaceable ground cable. The junctions where the cable makes contact at each end can be weather sealed (boots, grease).

 

[Compositepro]

Interesting problem. It should be posted in the corrosion engineering forum. If both parts are grounded then they simply cannot be electrically isolated from each other.

Grounding through diodes might provide enough forward voltage drop to stop galvanic currents but still provide a safety ground. I have no idea if that is allowed by electrical codes, but isn't this basically what happens with cathodic protection systems?

Paint will still protect these parts from corrosion.