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Blog posts tagged with 'Parts'

Medium Voltage Load Break Switches





Medium voltage load break switches control power to circuits with voltage ratings from 1kV to 52kV. They are used in a variety of applications and are differentiated from non-load break switches because as the name suggests they can safely be opened while power is flowing through the cricuit that they are installed in.

Applications include:

  • Selector Switches - Sometimes called A-B switches which select which power source will be used to energize the primary of a transformer.
  • Power Distribution - A group of switches, can be with or without a main, which direct power to various locations in a factory or other large facility.
  • Primary - For a single transformer powering a secondary switchgear.
  • Isolation - To de-energize equipment not being used or so that the switchgear can safely be serviced.

Typical ratings for the most common switches used on a 2.4kV through 15kV will have a continuous rating of 600 amp but are most often fused well below that.

They can be designed for use both indoor and outdoor and are used to interrupt the flow of power under both normal and emergency situations. They are most often operated manually but some are also equipped with a motor driven mechanism with a shunt trip which allows them to be opened and closed remotely.

The components of a medium voltage load break switch include the switch body and housing, contacts and mechanism and arc extinguishing medium. The arc extinguishing medium can be air, vacuum of SF6 (sulfur hexafluoride) gas. Vacuum and SF6 gas are used when a medium is needed to provide effective current interruption with minimal contact wear. Air is a cost effective option, especially if the switches will see minimum cycling.




As with any mechanical or electromechanical device, regular scheduled maintenance is required. This includes visual inspection, lubrication of mechanism and contact joints, testing of insulators and conductivity testing of the closed switch to ensure minimum internal resistance. Frequency of this maintenance will vary depending on factors including frequency of operation and environmental considerations. Failure to properly maintain these switches can and will result in non-scheduled power outages with damage to surrounding property and can injure or kill personnel in the area.

Many switchgear installations are in service well past the time that the OEM stopped supporting them or items may have long lead times which will extend the time of the unintended outages causing loss of production that run into tens or hundreds of thousands of dollars. This makes your local used equipment dealers like National Power Equipment invaluable. NPE not only has switches and parts in stock and available for quick shipment but also the experience and knowledge to guide you through pitfalls in things like parts interchangeability that wouldn't otherwise be apparent in the field. As always, knowledge and information is critical. Gather not only nameplate information but photos of both the overall switch and details of the parts in question. This will make it much easier for NPE to live up to its motto of "The right part, at the right price, right now!"

Are we in an Economic Recession now?



Many say that we are currently in a recession, others say not yet but one is due to hit soon. Either way we are all dealing with rising prices, longer lead times and shortages in available equipment. At NPE, we are here to help recession-proof your business.

Here's how we can help!

* Used, reconditioned equipment is at least 40%-60% less expensive than buying new.

* Used, reconditioned equipment is always quoted from available inventory so there are no supply chain issues.

* All reconditioned equipment is tested and warranted for up to two years! That's longer the manufacturer warrented it as new!

National Power Equipment specializes in:

Pars for Equipment Maintenance and Repair- We can support you with parts and supplies to keep your breakers, switchgear and medium voltage starters safely maintained and running for years to come. Many of the most problematic parts are available online at Aftermarket Parts Store for Replacement Circuit Breakers or Switchgears ( Many of these parts are available as new and upgraded by NPE (or one of our partners) to eliminate the defect that caused the problem in the first place.

Increase Capacity - As your business grows we can help your switchgear grow with you! From simply supplying a breaker for a future cell or adding and entire unit substation we have the equipment and expertise to help you expand economicly and without down time. Circuit Breakers, Relays, Transformers National Power Equipment (

Equipment Upgrades - Solid State trip upgrades with reputable companies, such as Utility Relay, are one of our many specialties. Do you need to upgrade the ampacity of a line from say 1200 amp to 2000 or 3000 amp? We have the parts and experience to help there, too! Reconditioned Equipment (

Rentals and Exchanges - With an inventory of literally thousands of breakers in every configuration, we can help you avoid longer term outages and stay up and running by purchasing upgraded and warranted breakers and equipment and swapping them out with your existing breakers, then return your original back to us for credit for the core. Quick Ship Inventory for Reconditioned Circuit Breakers & Switchgears (

Technical Support - With decades of hands-on experience, literally 1,000's of breakers on hand for reference and huge online library of technical manuals and renewal parts books. Just give is a call and we will figure it out! Circuit Breakers, Relays, Transformers National Power Equipment (

As Bob Dylan said, "The times they are a-changin'!" but that doesn't mean change has to be bad. With NPE's inventory, staff and decades of experience, we can all navigate these economic changes and grow.

Give us a call 1-800-647-0815 or send us an email and let us know how we can help you.

Remember, at NPE our motto is "The Right Equipment, at the Right Price, Right Now!"

Get the right breaker or part- Right Now!

NPE's staff has been specifying breakers, parts and accesories for over 40 yrs. 

Our hands on experience starts with current production equipment and goes back to equipment dated in the 1940's!




Image of an expert at a circuit breaker supplier.



- Get more information than you think you'll need. Details matter!

- Photo's really are worth 1000 words! From the front, back, bottom they all help!

- Nameplates help but rarely have enough information and serial numbers are rarely helpful. 

- When in doubt go to our mobile ap NPE on the Go.  We'll walk you through the details and give you a place to attach some picture!



Find a Circuit Breaker Supplier That Asks the Right Questions

We realize we ask a lot of questions that's because we want you to get the right stuff- the first time

Just think what you might be getting from somone who doesn't ask these questions!

When you have questions about your circuit breakers, contact us today. If we can’t help you with your specific problem, we’ll tell you and direct you to someone who can. That’s what we are here for.

Where to Find Old, Discontinued, or Refurbished Circuit Breakers from General Electric, Westinghouse, Allis Chalmers, and More

Trying to find replacement circuit breakers for your facility? It’s time to review a few facts.

  • Over 75%* of Switchgear running commercial and inustrial facilities is over twenty years old
  • Original equipment manufacturers consider many of these obsolete and no longer support them with new components yet the with proper maintenance will remain reliable for many years to come.
  • Used equipment dealers are your source for equipment and solutions to stay up and running:
    • Safely
    • Reliably
    • Economically

National Power Equipment Inc's (NPE) warehouses are filled with thousands of circuit breakers and switchgear cabinets, and tens of thousands of parts. These product lines date all the way back to World War II, and its staff is well versed in specifying equipment for them.

National Power Equipment’s “Class One” process of reconditioning equipment brings equipment back to “like new” condition. The process includes:

  • Breaker disassembled to its smallest components and inspected for wear and damage.
  • Parts re-plated, stripped, and painted or buffed and polished to “like new” condition.
  • Breaker reassembled with new wiring and upgrades and testing to industry standard.

An old industrial circuit breaker for sale.

Available Old, Obsolete, and Discontinued Circuit Breakers

NPE warehouses a wide variety of old, obsolete, re-manufactured, and refurbished circuit breakers, specializing in low voltage (600 Volt AC or less) through medium voltage (15KV) circuit breakers, switchgear, and parts. Our inventory includes equipment from the following circuit breaker brands:

Keep the Power Running with Replacement Parts

In order to maintain your equipment, you're going to need access to parts!  

These parts can include relays, transformers, trip devices, fuses, and switchgear and don't forget our Aftermarket Parts Store!

The Aftermarket Parts Store is loaded with the kind of hard-to-find parts that always seem to be needed. These parts are available as new copies of the original part, often complete with improvements that will help keep the part in service longer than the originals!

Hard-to-Find Circuit Breakers

If you’re unsure where to look for an older or obsolete circuit breaker, start with our circuit breaker equipment search or our mobile ap NPE on the GO to see if the product you’re looking for is in our inventory. If you can’t find what you’re looking for, there’s a good chance we know how to help. Contact us for those hard-to-find circuit breakers or equipment, and we’ll be happy to navigate you in the right direction. 

At NPE our motto is always, " The right equipment, at the right price- right now!"

 ED 12/22

*Based on informal survey of customers 1994-1996