Posts Tagged ‘obsolete circuit breakers’

Vacuum Technology Obsoletes Air Circuit Breakers

June 11th, 2010 Comments off

MIDWEST recently sold a 2500 amp 15 Kv old used air circuit breaker for $5000.00.  It was in excellent condition and years ago it would have sold for $25,000.00.  One might think the reason for the big drop in price is because of the age.  But the biggest reason is the use of vacuum technology in 15 Kv class circuit breakers.  Vacuum breakers are used to replace air circuit breakers in new 15 Kv switchgear. And many old medium voltage air circuit breakers have been replaced with new vacuum breakers or retrofitted with vacuum technology. 


Maintaining and Testing 5 Kv and 15 Kv vacuum circuit breakers is a lot easier than the old air circuit breakers.  And the vacuum breakers are a lot easier to handle.  An old or obsolete air circuit breaker could weigh 1500 pounds.  The new vacuum equipment is half that.  The biggest difference is the simple replacement of the old heavy arc chutes with the simple vacuum bottles. For an historical perspective, the early 1900s saw the use of big old oil circuit breakers.  The mid 1900s began the use of air circuit breakers. And the late 1900s began the use of vacuum breakers.  MIDWEST has worked on all of them and the vacuum breakers are just so much simpler to service.  Some older electricians and switchgear service technicians do not trust the vacuum circuit breakers as a safe circuit open device.  I wouldn’t trust vacuum circuit breakers or old air circuit breakers or obsolete oil circuit breakers as open circuit protection. The circuit breaker must be racked out and, of course, the circuit grounded before any circuit work or equipment maintenance. By racking the breaker out, one has a “visible open.”  Medium voltage air circuit breakers are an example of equipment becoming obsolete long before they actually wear out, all due to new technology. 

Expensive Small Replacement Circuit Breakers

May 28th, 2010 Comments off

How is it possible that a very small replacement circuit breaker, weighing only 2 pounds, would cost over $500 when a large replacement power circuit breaker weighing 200 pounds might be less than $1000?  MIDWEST frequently gets questions similar to this one.  The basic answer is economic supply and demand, the most fundamental law of a market driven economy.  A crude paraphrase would be “If the supply of a product goes down and the demand for the same product goes up, the cost of the product will increase.”  There are more people chasing fewer available goods, or circuit breakers.   In the world of supplying replacement circuit breakers, there are some small breakers that are no longer manufactured and are very rare, very difficult to find in the secondary market of used, reconditioned, and obsolete replacement circuit breakers.  For example, there are small molded case circuit breakers that you can hold between two fingers, but they cost over $500.  These breakers are no longer made. They are fairly common in some manufacturing facilities, but they are just not available. There are very few of them for sale and they are becoming scarce.  This is classic low supply and high demand.  On the other hand, there are large circuit breakers that are so common that they are not worth much more than scrap value.  A zillion of them were made.  Although they are no longer manufactured, they are a “dime a dozen,” so to speak. The supply is so large that it far exceeds the demand.  


The high cost of rare replacement breakers is supported by the fact that they are still far less expensive than replacing an entire power panel.  The high cost may seem unreasonable to someone purchasing an item for the first time. However, human nature would tend to look at the cost of a rare item as being too high, but not think of the cost of an abundant item as being too low.  

Obsolete Circuit Breakers

March 24th, 2010 Comments off

The word obsolete, when used in the context of circuit breakers, is not used in the pejorative sense but rather, in this case, obsolete simply means no longer produced.


Take a Square D QE3200VH molded case circuit breaker, considered an obsolete circuit breaker. This is a 3-phase 200 amp breaker with a very high current interrupting capability still used widely in industry today. It can be found in many types of metering stacks. The Square D EHB34100 is another in a family of obsolete circuit breakers still in wide use today. These two examples represent an enduring part of breaker history forming a strong and ongoing niche in the used breaker market.


Besides saving up to 70% of the cost of a new breaker when buying used, it may be the only good choice you have. Only the used electrical equipment market supplies replacement breakers for breakers in use but which are out of production. Panel board lineups are designed for specific types of breakers. It would not be feasible to replace a defective breaker in a lineup with a different type or style of breaker other than what the panelboard was originally designed to use.


Used circuit breakers should come with a warranty. In most cases you can expect a one year warranty on used circuit breakers, the same time offered by manufacturers of new breakers.  Always confirm the warranty.


Do obsolete circuit breakers meet the same national testing standards as new equipment? The answer is yes, if the used circuit breakers come from reputable suppliers that properly service and test the circuit breakers before shipment.