Galvanic Corrosion of Neutrals

Galvanic Corrosion of Neutrals Q: My copper neutrals look green. Could our practice of bonding neutrals to the rebar in our vault structures lead to neutral corrosion?   A: Yes, copper carbonate does have a bluish-green hue, but copper carbonate is your friend. The copper carbonate patina protects the native copper underneath from corrosion. It’s…

Failure Causes III

Failure Causes III In my January 24th post, “Failure Causes I,” I provided a partial answer to an inquiry seeking to understand if rejuvenation technology was appropriate for the “many types of aging factors” from which his firm’s circuits might suffer. We learned that 39% or more of all circuit failures are component failures and…

Using TDR to Identify Neutral Corrosion and Splices

Q: The blog post titled Neutral Corrosion — How Much Is Too Much? includes a waveform from a TDR (time domain reflectometer, often called a radar) that is used to pinpoint bad sections of cable neutral. The TDR is also used to pinpoint splice locations on the cable. How does the TDR determine the neutral corrosion and splices on the cable? And how is the waveform read to tell them apart and to pinpoint their locations?

Neutral Ampacity & Re-closers

Q: In Exhibit E of your proposal you state that cable replacement should be utilized rather than cable injection if the “cable neutral has lower than required ampacity …” I was able to find on Novinium’s website the limits for neutral corrosion, but nothing on the neutral ampacity limits. What are the neutral ampacity limits? Keep in mind that on three phase cable installs we use one-third neutrals. In Exhibit F of your proposal you define “Abnormal Operational Excursion(s).” One of the identified excursions, item (3), is “repeated operations of re-closers.” We use re-closers on all of our circuits. Does this mean that the warranty is void?

Neutral Corrosion Progression

Q: Can you please explain the rate of neutral corrosion? Specifically, do neutrals corrode linearly or in some other fashion? Also, an engineer asked me about stray voltage. We were discussing how Novinium will provide a warranty for a cable segment if 50 percent of the neutrals are good. He said, “Okay, but because of the neutral corrosion, I am having stray voltage issues affecting livestock on dairy farms. This can kill livestock. Stray voltage is also showing up sometimes on communications circuits.” How should I respond?