Cathodic Protection - in house or outside contract?

[Truemanator]

We're working on a hydroelectric site with a steel penstock entering the powerhouse. There's a copper grounding grid in close proximity to the penstock, bringing concerns we may need to design cathodic protection.

I've spent a bunch of time working on it and everything seems very do-able. However, I did notice that there's people out there that do corrosion engineering for life. I'm an electrical power engineer type.

I've determined protection on the system is a good idea considering the circumstances of the structure. Would it be wise to get an outside expert contractor to design the protection system or would you guys consider it a task do-able if learned? I want to avoid investing too much more into this project.

 

[ScottyUK]

Confronted with a fairly similar situation I employed a contractor to do the design & installation, and a consultant to act as Owner's Engineer. The guy who did the OE work picked up on a lot of things that I would have missed and resulted in a system which actually performed very well instead of one which had the appearance of performing well. I also learned a heck of a lot about CP in the process.

Depending on what you are protecting, don't look at the short term bottom line. Look at the knock-on effects on your operation of losing the penstock or whatever you are trying to protect. In my case it was main condenser lines for a CCGT plant, loss of which would have been a commercial disaster.


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If we learn from our mistakes I'm getting a great education!

 

[lexkyphil]

I work in the natural gas business, particulary compression stations and we always do passive or active cathodic protection. We use an extensive grounding system that has insulated copper wire and exposed magensium anodes, 32 lbs and connections to rebar in all concrete structures. It works well.

 

[fdac]

I would suggest getting a CP engineer to design any CP systems - experience and qualifications are required.

I assume the inlet pipe is buried, so that CP can actually be used (Many hydro penstocks I've seen are above ground). You then need to electrically insulate the buried pipe from the earthing grid for CP to be practical.

Getting a good CP engineer on board will save you a lot of headaches!