Posts Tagged ‘general electric’

Circuit Breakers: We’ve got what you need – All Manufacturer’s

February 23rd, 2015 Comments off

Circuit Breakers: We’ve got what you need.  MIDWEST sells reconditioned, used and new Circuit Breakers.  Call today at 800.803.9256!

All manufacturer’s available – Cutler Hammer, General Electric, ITE, Siemens, Square D, Westinghouse, ABB, Airpax, Allen Bradley, American, ASEA Brown Boveri, Bryat, Bulldog, Challenger, Crouse Hinds, Federal Pacific, Fuji, Gould, Heineman, Kraus Naimer, Merlin Gerin, Milbank, Mitsubishi, Moeller, Murray, National, Sace, Sylvania, Telmand, Thomas and Betts, Trumbull, Tyco, Vois Worth, Wadsworth, Zinsco, etc.

Image of Circuit Breaker Main and Arcing Contacts

July 9th, 2012 Comments off


Circuit Breaker Main and Arcing Contacts with Copper Splatter

Circuit Breaker Main and Arcing Contacts with Copper Splatter

When discussing circuit breakers, we like to have good images to show the difference between the main contacts and the arcing contacts. When a circuit breaker opens, the main contacts should open partially first before the arcing contacts start to open. There should be no arcing damage to the main contacts because the arc interruption takes place between the arcing contacts. This protects the current carrying surfaces of the main contacts so there is minimum contact resistance at the main contacts. Good contact surface means no overheating. For the same reason, when the circuit breaker closes, the arcing contacts close first, suffering any arcing damage. After the arcing contacts are closed, the main contacts close. All this keeps the main contacts in good condition. The arcing contacts are enclosed in something called an arc chute that extends and separates the arc until it is extinguished when the circuit breaker opens. When the arc chutes are contaminated with dirt or high humidity or interrupt very high loads or fault currents, the arc chutes take a beating. Whether you’re talking about Square D circuit breakers, Cutler Hammer circuit breakers, Siemens, Westinghouse or GE General Electric circuit breakers, molded case circuit breakers, power circuit breakers, or medium voltage air circuit breakers, the function of the arc chutes is the same, take a beating to protect the main breakers. The attached image shows the damage to the stationary and movable arcing contacts and to the arc runner that extends into the arc chutes to extend and divide the arc until it is extinguished. The main contacts, the 16 curved segments across the middle of the image, are in good shape. No arcing damage what so ever. This image is from a medium voltage air circuit breaker.

Cutler Hammer Circuit Breaker Trip Indication

April 20th, 2012 1 comment


Cutler Hammer LD3450 Molded Case Circuit Breaker with Handle In Trip Position

Cutler Hammer LD3450 Molded Case Circuit Breaker with Handle In Trip Position

MIDWEST gets lots of phone calls from folks desperate for a little technical help. Sometimes they know very little about electrical equipment, circuit breakers for example. These are the most difficult calls because the caller may be putting themselves in harms way and not know it. We could tell them what to do, but unqualified people in the electrical power world need to hear “Hire an electrician, call a qualified person, call an electrical contractor.”  We might tell them to send us a picture of their circuit breaker and we can help them identify it, but get a qualified person to service or replace it. All too frequently the caller wants someone to tell them it is okay to just turn the breaker back on after it has tripped for no known reason. This can be very dangerous and against the code. For example, a maintenance mechanic called about a Cutler Hammer 450 amp molded case circuit breaker. This was a Cutler Hammer Catalog Number LD3450 circuit breaker. The breaker had tripped and one area of lighting in their plant was off.  He was told to “find the problem and turn the breaker back on.” Maintenance mechanics tend to be very resourceful individuals. And that is precisely what makes them dangerous around electrical equipment. They can fix mechanical problems, but most are not qualified around the dangers of electrical problems. In this case he thought the Cutler Hammer breaker was broken because the handle was in the middle and he could not close the breaker. It would have been easy to tell him how to reset the breaker so it would close. He was not overly interested in our requirement to have a qualified person investigate why a 400 amp Cutler Hammer breaker tripped. A lot of power or fault current went somewhere. The recommendation would have been the same for a GE General Electric circuit breaker, or Square D, Siemens, or old Westinghouse circuit breaker.  If the trip handle is in the middle, it tripped for a serious reason.  A qualified person has to investigate why. You can not just throw the power back on. And if you do not know how to reset a Cutler Hammer Series C industrial circuit breaker, you are not qualified.

Seeing Is Not Believing – Barrels of Junk Circuit Breakers

March 12th, 2012 Comments off
Barrel of Scrap Circuit Breakers

Barrel of Scrap Circuit Breakers

This is another blog on MIDWEST’s barrels of junk circuit breakers. More specifically it is about the difficulty of not believing something you can’t see. This human factor can frequently be a challenge in our world when a customer has a perfectly good looking circuit breaker and we tell them it is no good and they need a replacement circuit breaker that will cost $3500.00. They understand the words, but their emotional pocket book says “But it looks okay.” Even after being presented with the test results or pictures of the inside of the breaker that reveal the deficiency or damage, they find it hard to believe what their brain is telling them isn’t true, “Because it looks okay.” In our world of reconditioning circuit breakers and remanufacturing circuit breakers, we frequently scrap out equipment that looks in perfectly good condition. Usually the reason for tossing out, say a Square D NA361200circuit breaker, involves deficiencies that can not

Square D NA361200 Circuit Breaker

Square D NA361200 Circuit Breaker

be seen physically, unless you remove the cover or thoroughly test the circuit breaker. Whether a reconditioned GE General Electric, Square D, Cutler Hammer or Siemens circuit breaker, if the inspection or test results say junk, out it goes. And keep in mind, some circuit breakers are not built to be happy if you remove the cover. You need to know what you’re doing. Recently we had an electrical contractor stop to pick up several reconditioned Cutler Hammer circuit breakers. He walked by the barrels labeled “Scrap Breakers” and he looked like he saw a little gold mine. He really didn’t like the idea that all those breakers were actually junk and were being scrapped. The contractor in him told him these breakers were worth a fortune. Even after showing him some of the new looking circuit breakers that had the covers off revealing visible deficiencies, all he could say was a skeptical “Hmmm.”  Even we sometimes grunt a little “Hmmm” when we toss out a $3000.00 piece of junk.

Circuit Breaker Reset Tests

January 11th, 2012 Comments off
1600 Amp General Electric Air Circuit Breaker - Catalog No. AK-2A-50-1

1600 Amp General Electric Air Circuit Breaker – Catalog No. AK-2A-50-1 Available at

A customer called MIDWEST to ask why we did something called a “Reset Test” on his circuit breaker. He said he has had circuit breakers tested by switchgear service companies for nearly 30 years and never ever saw something called a circuit breaker “Reset Test.” He has Square D circuit breakers, Westinghouse circuit breakers, General Electrical circuit breakers and newer Cutler Hammer circuit breakers. He checked some of his old test reports and found no “reset tests.”  He had never used MIDWEST before, so he was pretty interested when we explained the reason and procedure for the reset test. The reason was a very pleasant surprise because it gave him greater confidence in the proper performance of his circuit breakers.  MIDWEST started using the circuit breaker “reset test” many years ago. It’s not a standard test procedure. You won’t find it in the text books or instruction manuals. You will find it in MIDWEST’s Training Manual under ‘Scars,’ meaning experience. It’s a carry over procedure from testing old dashpot type air circuit breakers and insulated case circuit breakers and molded case circuit breakers. The reason for the test is that occasionally, seldom but occasionally, a circuit breaker will nuisance trip when put back into service after it has been high current tested. For example, a 1600 amp air circuit breaker, after high current testing, might nuisance trip instantly at 500 amps.  Basically the over current device failed during the high current testing. This was far more common with older “non electronic” over current devices. New electronic over current devices are more reliable, but not perfect. Strange things happen. We are not talking about the service technician forgetting to put the settings back to the correct positions. We are talking about an actual defective device. The test only takes moments. In the interest of quality control, the reset test addresses the “consequences of failure” as opposed to the “probability of failure.”

Yes, we are paranoid about safety and quality.

Perfect Square D MA36500 Circuit Breaker an Ornamental Reminder

October 28th, 2011 1 comment
Square D MA36500 Circuit Breakers For Sale at

Square D MA36500 Circuit Breakers For Sale at

On one of MIDWEST’s Switchgear Service Desks is a Square D molded case circuit breaker in mint condition. It just sits there, in a place of honor, as a reminder that appearances may outright lie. It has nothing to do with whether or not the circuit breaker is Square D or a Cutler Hammer HLCG3400 or a GE General Electric TJK436400WL or any other manufacture. It is there as a reminder that you can’t tell the condition of the inside of the breaker, the operating condition, based on the outside appearances. We see breakers that look like junk, but test out perfectly. And, as in this case, we see breakers that look mint and are junk. We used this circuit breaker because it looks like it is in such great condition. Looks great, opening and closing sounds right and feels right.  But, when we removed the cover, the contacts were what we call, and this is a technical term, fried. Moveable and stationary, main and operating contacts were burned, brown, and blasted. The inside of the arc dividers were charred. The breaker was fatally damaged and could not be used. But it looked in mint condition.  This is a great training aid and we kept it just for that reason.  There is a tendency to make technical judgments based on appearances. This is human nature. But is does not apply to the technical world and it certainly does not apply to the electrical switchgear world.  We’ll call this, “Breaker fallacy number one.”

Circuit Breaker Trash Barrel – Fried Load Terminal

February 28th, 2011 Comments off
Blog Barrel of Scrap Breakers

Blog Barrel of Scrap Breakers

This is another circuit breaker trash barrel blog. I went to one of the many barrels of trashed circuit breakers and grabbed a breaker out of one of the barrels. We thought these barrels of discarded breakers would be a gold mine for useful circuit breaker maintenance, testing, and reconditioning blog information. So today’s blog is about a Cutler Hammer ED3200, style number 6610C75G04, 200 amp molded case circuit breaker. The breaker looks great. Looks like it was cleaned up but then thrown out. It was. But the operating mechanism was defective.  It would not latch and it would not close the circuit breaker. The cover had indications of overheating at the center pole of the load side of the circuit breaker. There was a piece of the copper conductor still in the load side center pole terminal. The feeder had been cut off rather than remove. The strands of the conductor and the lug were fried. That’s a technical term for overheated to the point of brown discoloration, corrosive appearance on the surface of the lug and on the set screw holding the conductor in place. The metal tab under the lug surface was brown from overheating. The top view showed the top of the lug set screw was also burned and brown. We know from experience that the lug can’t be removed without damaging the load side center pole tab of this Cutler Hammer ED3200 200 amp circuit breaker. We know the heat has damaged the trip device and dried out the interior operating mechanism. A breaker damaged like this, whether a Square D, GE General Electric, Siemens or Westinghouse circuit breaker, is junk and needs to be destroyed. So into the scrap barrel it goes. Warning, one might ‘fool around’ with this breaker and get the operating mechanism to function and maybe finally get the old piece of cable out, but the breaker is still junk. Put it on the table, come back in a week and I’ll bet you it doesn’t work again. If you removed the cover, you would instantly see why.