Why Switchgear Fails and How to Fix or Prevent It

When it comes to dealing with complex power systems, the adage is: “It is not a matter of if, but when it will fail.” And when that day comes will you be prepared? Here at French Gerleman, our goal is to help our clients with identifying weak links in your power system and knowing how to handle them when they go down. Any switchgear that is more than 30 years old is considered outdated, and our region is home to a lot of outdated switchgear. So it is important to know how to handle the situation if you are subject to it.


History of Switchgear in the Midwest

The Midwest has a rich past of being a formative area in the history of American electrical manufacturing. Due to copper shortages brought on by war time starting at WWI and continuing into the 1950s, manufacturers switched from copper to aluminum alloy 6061. While aluminum 6061 is a good conductor, it is an inferior product. Yet, between 1964 to 1972, it was installed in over 2 million homes and businesses. The aluminum has tremendous expansion and contraction characteristics. Dissimilar metals cause the aluminum to oxidize which leads to insulation instead of conduction. Most of the old switchgear we see is equipment from this time period. Switchgear installed in those date ranges can be problematic and even dangerous.

What Can You Do If You Have Old Switchgear?

  1. Replace the entire line-up – If you have a facility that cannot have a long downtime, you need to have a plan in place. This is the best option, but can be a challenge due to the location, purchase price, or the difficulty of installation.
  2. Buy new or used breakers of the same type – We at French Gerleman never recommend used breakers as they can be a dangerous option.
  3. Upgrade the trip unit – This is the “brain” of the existing breaker. An upgrade allows new trip unit-controlled capabilities (metering, comms, ZSI, maintenance switch etc.)
  4. Retrofit the existing breaker – Retrofitting with a modern breaker also includes a trip unit upgrade.

All of the above options involve risks or tradeoffs. But if you wait until a failure happens, your only option will be a full replacement.

How to Prolong the Life of Switchgear

Regular preventive maintenance is key to keep your electrical systems running properly and extending the life of its components.

  1. All parts should be cleaned and inspected for damage or anomalies, including contamination. The windings should be reinsulated as appropriate. We can assist your team with thermography services to inspect the parts in your switchgear and transformers. The scans can provide you an accurate indicator of potential problems.
  2. Assess insulation resistance by checking between motor leads and ground. This will determine the condition of the ground insulation.
  3. Large duty circuit breakers (225 amps of above) should be electrically trip tested by a professional on a regular basis to ensure proper operations of the trip elements and the trip linkages.

Dry type transformers need the same treatment. If a transformer fails, it can irreparably damage upstream and downstream equipment.

  1. Clean the enclosure of any dust and dirt accumulations and ensure that the vent openings are free from obstruction.
  2. Routine testing is essential. Testing should include an insolation resistant test, a dielectric absorption test, and a power factor test.
  3. Clean and inspect for damage or anomalies including grounding and bonding.

French Gerleman represents numerous manufacturer partners who can help you prolong your gear or identify your potential issues. Our goal is to help you expand the lifespan of your existing gear if you are not in a position to fully upgrade at this time. And the great news is, we are just a phone call away! Reach out to your French Gerleman Account Manager for assistance or contact us online today.

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