No good electrical testing field story starts with “everything went perfectly.” Inevitably, things do not go according to plan. Breakers of all types, makes, and models are the source of great stories and hard lessons learned under pressure to get a circuit back in service. The purpose of this article is to share common issues that fall into a few categories across a variety of breakers. As an old friend of mine who worked for GE once said, “We only make two kinds of breakers that I hear about: Those that don’t open and those that don’t close.” On that note, let’s dig in.
IT’S AN ELECTRICAL ISSUE
Memes related to the arguments that can occur when an electrically operated (EO) breaker fails to work correctly are common. The mechanical guy points his finger at the electrical guy, and the electrical guy points right back. The answer lies in a more holistic approach to breaker troubleshooting.
A notable example is a recent issue where a VCP-W 27 KV medium-voltage (MV) breaker failed to open electrically while the operator was attempting to bring a turbine generator off-line. With the breaker on the floor and using an external power source, everything worked perfectly. However, the breaker wouldn’t trip when placed in the test position. An attempt to use an available spare also failed to trip.
Electrical problem, right? Working through the control circuit, one device and interlock at a time, proper control voltage was found all the way up to the terminal strip that goes to the secondary contacts block. Inspection of the secondary block revealed that several pins had been pushed out of the block (Figure 1). This created an open circuit between the control system and the breaker. Correction of this mechanical issue fixed the breaker’s operation.
A related issue can occur on MV breakers with sliding secondary contact blocks like GMI and Allis-Chalmers breakers. It’s always frustrating at the end of the outage when you close the last breaker and nothing happens. Before you go through extensive troubleshooting and second-guessing whether that breaker you just tested works, grab a flashlight. Look closely at the left side of the cubicle and breaker to ensure that all the fingers of the breaker are in their grooves/slots (Figure 2). This problem occurs mostly in vintage gear that has had time to get out of square or if the floor plates are less than solid. Some of you know exactly what I’m talking about.
It will take some mechanical work to get things to line up, and I just saved you hours of head scratching the next time your breaker doesn’t operate electrically.
LV breakers with secondary connection/ contact, such as low-voltage (LV) Masterpact NW breakers, among others, can also have issues with secondary blocks. A recent installation identified numerous damaged secondaries (Figure 3).
The damage occurred when the secondaries of the breaker were binding on the cell side while being racked in. As a reminder, if you feel anything binding or otherwise unusual when racking, stop and investigate.
MORE ELECTRICAL CHALLENGES (STILL MECHANICAL)
Electrically operated (EO) breakers are filled with limit switches. If any one of these switches has a mechanical failure, it will affect the breaker’s operation. Examples include the limit switch that prevents a breaker from closing if the closing springs are not charged. Once the breaker opens to de-energize, the “a” contacts on either side of the trip coil open the trip circuit to prevent damage to the trip coil. If these contacts don’t work, the breaker won’t trip.
While not directly related to tripping or closing a breaker, the motor cutoff limit switch is one of my favorites. I have routinely experienced the issue on both MV and LV EO breakers. To a rookie technician, a failed motor cutoff limit switch can lead to a burned or failed charging motor. To an experienced technician, recognizing that the motor has continued to run after the springs have charged it leads to a hasty scramble to locate and pull control fuses to de-energize the motor circuit. This one lesson is a valuable illustration of what it takes to be a qualified electrical worker (QEW). A QEW must be familiar with the operation of the equipment (Hey, this motor is running too long!) and also be familiar with the construction of the gear (Where are those fuses?!?).
IT’S ALWAYS A MECHANICAL ISSUE
No manufacturer is exempt from the wear and tear caused by harsh environments and neglect. Even the most well-engineered breakers will develop mechanical failures without proper upkeep. Dust, moisture, and heat accelerate degradation, making routine maintenance essential.
When lubrication is ignored, breaker linkages stiffen, and pivot points seize. Over time, these issues lead to slow operation, failure to trip or close properly, and even catastrophic failure during a fault condition. What should have been a simple lubrication task turns into a costly replacement or unexpected downtime. Using the right type and amount of lubricant, applied at the correct intervals, prevents binding, excessive wear, and increased operating forces that can lead to failure.
While all brands can have issues, I’m going to identify a few breaker types that seem to be more susceptible in my experience, along with input from others. There is no reason to keep these known pain points a secret. Enjoy the list and note that similar failures can be seen in a variety of manufacturers and breaker types. Note that the performance of corrective actions should be done by a QEW in an electrically safe condition.
GE AK Breakers
On this style of breaker, the trip latch is notorious for being sticky and not dropping into place to allow the breaker to close after a charge operation (Figure 4). AK–25s are the easiest example. Rotate the charging handle to 9:00. During the rotation back to 6:00, if the breaker does not close, the trip latch needs attention, including proper lubrication — or more often, correcting improper lubrication (WD40 or similar).
Another common challenge if the breaker doesn’t close in the cell is that the racking mechanism interlock on these breakers is a sleeve that slides along the outside of the round racking shaft. It is easy to miss the fact that it didn’t slide back out after removing the racking handle.
Most breakers can have mechanical issues related to improper lubrication, including Siemens RLs, Westinghouse/Cutler Hammer DSs, and ITE/ABB K-lines.
GE Power Break II (PBII)
If you come across one of these in the field, be prepared for this breaker not to close or charge if you open it. Unlike the AK, a little lubricant will not fix the issue. The issue with these breakers is the stop block (over-travel bumper). Over time, the bumper material degrades (Figure 5). This degradation allows the mechanism to overtravel, and the breaker trips free. In some cases, it won’t even allow the mechanism to charge. The fix requires removing the breaker from service and installing a new block kit. You can get more information by searching for DEH40466 Installation Instructions.
Pro-tip note: After closing a mechanically operated PBII breaker, manually charge the closing springs. This removes the force the mechanism places on the stop block, allowing the bumper to recover, in theory, extending its serviceable life. Other breakers with over-travel issues can include DBs, GE AKRs, and Siemens LAs.
Sq-D P-Frame Breakers
It might just be me, but I have had many poor experiences with these breakers (Figure 6). You might have one that operated during a fault and will not reset, or you opened it for maintenance, and you get that sick feeling in your gut because you know the mechanism isn’t properly engaging the closing mechanism. To make matters worse, these are insulated-case breakers and technically not intended to be serviced, particularly in the field. Encourage customers to upgrade to a modern breaker version of the Sq-D breaker line.
Siemens RL Breakers
Several things to remember when it comes to these breakers (Figure 7):
- Broken phase barrier boards are routine, probably because they stick up above the frame and arc chutes. Handle with care.
- These are difficult to close because the close hood is behind the charging handle. Many of us use the racking handle or a long screwdriver to close them.
- Follow all instructions to avoid damaging the breaker while racking. Depress and hold the red trip bar while opening the racking window.
- The RL discussion would be incomplete if I didn’t mention what a pain these can be to remove and reinstall the arc chutes for inspection of the breaker contacts.
Push the trip lever for racking.
SOMETIMES IT’S THE OPERATOR (I MEAN YOU)
I had a particularly bad experience in the middle of an outage because I ignored a warning label. The breaker I am talking about is a Sq-D Fluarc. The warning was to discharge the closing springs before removing the breaker from the cell (Figure 8). I didn’t follow that simple instruction and pulled the breaker from the cell. Like many — if not all — breakers, the spring discharge cell interlock discharged the springs. When it did, I heard parts jingle inside the breaker, and a retaining clip fell to the ground under the breaker. After removing the cover from the front of the breaker, I found the closing spring loose from its attachment point on the charging mechanism.
I don’t recall which friend I phoned to see how to reattach the spring. What I do remember is that a 500-MCM two-hole cable lug saved the day. I have made it standard practice to close the breaker and then open the breaker (in the disconnected position) before removing it from the cell on all breakers.
Regularly enough to make it worth noting, I get a call from a customer or technician with a VCP-W that won’t close. The first and easiest thing to check, especially if the breaker was racked out and back in, is the position of the racking mechanism (Figure 9). There is a nice feature on these cubicles where the racking mechanism lock-out slide can be used to hold the racking interlock back, exposing the racking shaft head. Basically, it makes racking the breaker in/out easier. The trouble is remembering to release the interlock when you are done. It’s an easy fix to open the door, release the slide, and close the breaker. Don’t feel too embarrassed when it happens to you…most of us have done it.
SUPERIOR PERFORMANCE TIP
Have you ever done LV breaker testing and needed to change settings? Of course, you have. Have you ever forgotten to put them back to the as-found settings? I like to take a picture of the settings before the breaker leaves the cell, then a final picture when the breaker is back in the cell to compare with the previous pictured settings (Figure 10). The time stamps of the two pictures can be used to defend against any questions about possible setting discrepancies.
This information came in handy when another contractor (working for another person at the plant) was asked to make changes to breakers after we departed the site. When issues ensued with the changes that our plant contact was not aware of, the ability to be able to document the as-left settings absolved us of responsibility.
CONCLUSION
Circuit breaker reliability requires vigilance, routine operational verification, and periodic maintenance to ensure optimal performance. As this article has shown, failures attributed to electrical issues often originate from overlooked mechanical faults, especially in secondary contact blocks, limit switches, and lubrication deficiencies.
No breaker, regardless of make or model, is immune to the wear-and-tear of time, environment, and human error. Proper maintenance, a thorough understanding of equipment operation, and respect for warning signs are key to preventing failures and ensuring safe operation. In the end, a little attention to detail can save hours of frustration and keep systems running smoothly.
Mose Ramieh is Vice President of Business Development at CBS Field Services. A former Navy man, Texas Longhorn, Vlogger, CrossFit enthusiast, and slow-cigar-smoking champion, Ramieh has been in the electrical testing industry for more than 25 years. He is a Level IV NETA Certified Technician with an eye for simplicity and utilizing the KISS principle in the execution of acceptance and maintenance testing. Over the years, Ramieh has held positions ranging from field service technician, operations, sales, and business development to company owner. To this day, he claims he is on call 24/7/365 to assist anyone with an electrical challenge. That includes you, so be sure to connect with him on the socials.