Circuit Breakers Blog – Expert Safety and Usage Information

Here is another MIDWEST real world experience. This time dealing with circuit breakers, specifically three old power air circuit breakers.  Because of the extremely difficult location of the breakers, getting equipment to test the old circuit breakers was nearly impossible. And the cost would have been astronomical. There seemed to be serious problems with the circuit breakers. These were bolted in place generator breakers and the switchboard they were in had to provide power at all times.  A short outage could be catastrophic. But the breakers were tripping and the generator operators needed to know if the breakers were the problem or if they had load problems somewhere in their power system. The circuit breakers had old oil dashpot type over current devices and the operators wanted to know if retrofitting the circuit breakers with new electronic over current devices would make their problem go away. So, during a rather tense meeting, MIDWEST recommended the following three tests on two poles of each breaker.  The first test would take about 3 seconds. The second test would take about 8 seconds. And the third test could take as long as 90 seconds. We thought these tests would be nearly 100% as effective as actual high current testing in determining the condition of the dashpot over current devices. These were not calibration tests. They were function tests. The first sophisticated test procedure was to look at the oil dashpots. If we saw signs of oil weepage out of the circuit breaker oil filled dashpots, the breaker over current protective devices, ie the oil dashpots, were deficient and the breaker should be retrofitted. Simple. The second test involved manually pushing the instantaneous lever of the old oil dashpots.  If the action and resistance was normal and the dashpot reset properly, no nuisance problem.  The third and last test was to simulate an over current condition by a slow steady push on the delay component of the dashpots on the outside phases. For a veteran in the maintenance, repair and testing of these old air circuit breakers, these checks are very simple and very reliable in detecting defective oil dashpots. The actual test time per circuit breaker took us less than 45 seconds. We were not calibrating anything, but we did determine that all three circuit breakers had defective over current protective devices and needed to be retrofitted with new electronic over current protection. This was done and their problem was solved. How the retrofitting was done is a good subject for another blog. By the way, these circuit breakers were located in Antarctica.

TJJ436300 General Electric Circuit Breaker

MIDWEST buys surplus, old, used, obsolete, and even ugly circuit breakers.  We are paranoid about the history and condition of these previously owned circuit breakers.  We are particularly concerned someone will try to sell us breakers that look good, but have been damaged by water.  We are especially cautious because of dramatic flooding in recent years. This week we got a call asking us if we wanted to buy like new circuit breakers that were flooded with water.  Our polite answer was a screaming “No!”  They were honest and told us the breakers had been flooded.  We will not even consider buying moisture damaged circuit breakers. They could even be brand new circuit breakers and still, no. 

These breakers could be cleaned up cosmetically so they look new and they might even pass the basic electrical tests, but we know they are still junk. If you tore a water damaged breaker completely apart, including the trip device and the operating mechanism, you would find rust and caked on dirt, even mud.  Under the stationary contacts, on the trip device hold down bolts, under the trip element, inside the trip element, everywhere in and under the operating mechanism.

The breaker may pass the insulation resistance tests, the contact resistance tests, and maybe even the over current tests. And, if you don’t bother to take the cover off, you might never know that the breaker was damaged by water or extreme humidity.  We know that plants that have been flooded will go through a thorough switchgear on site reconditioning process. Switchgear, including circuit breakers, will be restored to operating condition in an effort to get the power back on as quickly as possible. But these are emergency situations and getting replacement equipment quickly may not be possible.  So one should not compare such an extreme circumstance with the normal world of a Switchgear Service Shop. 

We want to know the history of equipment we purchase and we can not rely on that information being always accurate. Everything must be completely checked out, reconditioned.  And because equipment passes standardized tests, does not mean it is reliable for reuse.  Reconditioning will determine if it will be reliable after passing the standardize tests and MIDWEST’s other reliability centered tests. But testing alone does not determine reliability.

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.  

10.       If you haven’t discovered the great value of used circuit breakers you really should.

9.         The Karma given off from a used circuit breaker purchase pays rich dividends. You’ll have to experience it.

8.         Think of the future. Used breakers are of course green. The carbon credits you accumulate in this life do transfer to the next.

7.         Buying used circuit breakers saves time getting to work. Think of the time you’ll save walking from your car to your building with your new employee of the month parking spot. 

6.         Buying used breakers puts you in good stead with your significant other. No longer will you spend wakeful nights thinking about ways you can save your company money.

5.         Our used circuit breakers meet national testing standards.

4.         Our used circuit breakers are readily available. Manufacturers do not keep inventories of used breakers. Your breaker will be in your hands just as fast as preparation time allows. 

3.         Our used circuit breakers are fast and easy to purchase. Check out our web site at www.swgr.com to see how easy it is.

2.         Only used circuit breakers can fit right in as a replacement for out of production panel board or cubicle configurations.

1.         And the number one reason to buy used circuit breakers is it saves money, up to 70% off the cost of new.

What is it about these breakers that people like so much? In a word, simplicity ─ they are quick and easy to work with.

Most breakers such as the Cutler Hammer EHD3100, to give one example, use “details” (mounting bus details) to attach the breaker line side to the panel board bus. Details are an additional item at a slightly greater expense and are not necessary for Square D I-Line breakers.  I-Line breakers line side connections are finger clusters which connect directly onto the panel board bus making swapping out an I-line breaker as easy as drinking a cup of coffee in the morning.

The process is pretty straight forward:

First up, de-energize the panel board and lock out and tag out the switch supplying power to the panel board. Check voltage to make sure the panel board is dead and that it is not being back fed through another source. Remove the panel board dead front. Loosen the load side lugs and remove the load side cables from the breaker. You now have access to the single mounting screw holding the I-Line breaker in place. After removing the mounting screw, place a screw driver in the prying slot on the mounting bracket on the load side of the breaker and pry the breaker horizontally away from the bus running vertically down the center of the panel board. The breaker can now be removed from the panel board. Put the new I-Line breaker in place and using a reverse prying motion, slide the breaker horizontally into position such that the line side finger clusters make complete contact with the bus. Insert the mounting screw and tighten firmly. Do not over tighten this screw as it is a sheet metal screw designed to hold the breaker in position only. Reconnect the load side cables, then go ahead and install the dead front back onto the panel board.

At this point it’s always a good idea to exercise the breakers in the panel board, working the action by opening and closing the breakers several times. With the breakers in the off position in the panel board you are now set to power back up.

MIDWEST carries General Electric Circuit Breakers. Whether it’s a new, reconditioned, or used breaker, we are sure we can provide just the breaker you need. We stock thousands of General Electric circuit breakers in our inventory.

MIDWEST reconditions General Electric circuit breakers. Worn or damaged breaker component parts are tested and replaced if necessary as part of our quality control program. Over current devices can be retrofitted with electronic devices to assure state of the art over current protection. A low voltage air circuit breaker is disassembled. Insulating and current carrying members are cleaned and inspected and replaced if necessary. The breaker is reassembled and then put through a rigorous testing procedure to make sure everything properly checks out. The breaker would be tested for contact resistance, insulation resistance, and the over current devices would be tested to ensure they operate in accordance with the manufacturer’s trip curve specifications. Typical basic overcurrent functions would be long time, short time, and instantaneous pick up and trip capabilities. Some breakers contain ground fault capability as well.

Click Here for General Electric Circuit Beakers

Our staff is always excited to take your phone call and answer any General Electric Circuit Breaker questions you may have. We are proud to have served the electrical community since 1977, also the year the first Star Wars movie was released, (no connection between those events). Whatever your circuit breaker needs may be, we are sure we are your best solution. Our engineers have many years of experience with circuit breakers and power distribution equipment and they are always happy to answer any question you may have.

Sometime in January of 1942, the American intelligence community broke the Japanese code enabling the United States to track what the Japanese were up to. Circuit breakers contain their own type of code also. It may not be as intriguing or as sophisticated as all that, but the circuit breaker code tells its own story. Enter the circuit breakers catalog number. This number is the ID bracelet of the circuit breaker. Take the catalog number of a Square D KAL36200. We know it’s a Square D. The “KA” represents the series of the breaker. The “L” means the breaker has lugs. The “3” indicates the number of poles. The “6” the voltage class (in this case it’s 600 volts). The “200” indicates the frame amperes. So there you have it. The anatomy of a breaker contained in one simple number.

So when you call up with questions about circuit breakers, the catalog number is the key number to know.

Since 1977 MIDWEST has been in the business of servicing circuit breakers, which coincidentally was the only year in recorded history snow fell in Miami Florida. The two events are not related. We have seen many types and sizes of circuit breakers come across our shop tables over the years, ranging from medium voltage breakers, to low voltage air breakers, to molded case circuit breakers. Our experience has taught us well. Let our expert engineers and technical team help you with your circuit breaker concerns. Our office hours are from 7:00 AM to 6:30 PM CDT. Our technical support team is standing by and ready to assist you.