The EMSPEC vertical break switch is a high-voltage disconnect switch for 15 kV to 245 kV systems, rated from 600 A to 5000 A, built for tight phase spacing, heavy terminal loads, coastal sites and retrofit work.

A disconnect switch is what gives crews a visible open gap when they need to isolate a line, bus or piece of equipment. Because it sits outdoors for decades and has to work the same way every time, the details that matter are the materials, how the contacts engage and how easy it is to maintain.

This guide covers how the EMSPEC design works, what it is made of, the options you can add, and what to have ready when you ask for a quote.

How does the EMSPEC vertical break switch work, and where is it used?

According to the EMSPEC product page, the design focuses on getting full, repeatable contact every time the switch closes.

• Opening: the hinge is balanced so gravity pulls the blade back before it reaches 90 degrees.
• Closing: the blade swings down into alignment with the jaw, then pushes horizontally into it. EMSPEC says this axial entry guarantees full contact pressure on every operation.
• Contact: the jaw uses multiple spring-loaded finger contacts to reduce current density at the contact point.
• Verification: the closed position can be checked from the ground.
• Maintenance: the mechanical transmission components sit outside the current path, with no parts hidden inside the conductors, and the bearings use maintenance-free dry lubricant.

EMSPEC points to these applications:

• Installations that need minimal phase spacing
• Installations with heavy terminal pad loading
• Coastal environments, where the aluminum current path is a good fit
• Retrofit work, helped by field-adjustable mounting provisions on the base

The switch can be mounted horizontally, vertically or underhung, and operated by swing handle, worm gear or motor operator.

What are the key features and options?

Options you can add:

• Vacuum or SF6 interrupters
• Built-on grounding switch
• Key interlock system
• Silver-inlaid contacts
• Arcing horns and high-speed whips
• Outriggers and strain insulator provisions
• Ice hood, to prevent ice buildup on the contacts

Source: EMSPEC.

What should you specify before ordering a vertical break switch?

Have these ready when you ask for a quote:

1. System voltage and continuous current: the standard range is 15 kV to 245 kV and 600 A to 5000 A. Higher current or copper construction is a consult-EMSPEC item.
2. Mounting: horizontal, vertical or underhung, based on your structure.
3. Operating method: swing handle, worm gear or motor operator, depending on how crews or SCADA will operate it.
4. Interrupter: whether you need a vacuum or SF6 interrupter, or a plain disconnect.
5. Grounding and interlocking: a built-on grounding switch and key interlock, if your switching procedures call for them.
6. Environment: coastal salt exposure, ice (the optional ice hood), and any heavy terminal pad loading.
7. Phase spacing and retrofit constraints: the design is meant for minimal phase spacing, and the base has field-adjustable mounting provisions.

The EMSPEC page does not list basic impulse level (BIL), short-circuit ratings, applicable standards or model numbers. Ask for those, along with drawings, before you finalize a specification.

Frequently asked questions about the EMSPEC vertical break switch

What voltage and current ratings does it come in?

15 kV to 245 kV and 600 A to 5000 A. Copper versions and models up to 7000 A are available, so consult EMSPEC for details.

What is it made of?

The current-carrying parts are 6063-T6 extruded aluminum. Other parts are extruded aluminum or machined solid billet, including 304 stainless steel and hard-drawn copper. Contacts are field-replaceable, silver-plated hard-drawn copper, and the base is hot-dip galvanized steel.

Is it suited to coastal environments?

EMSPEC describes the high-conductivity aluminum current path as suitable for coastal environments.

How can it be mounted and operated?

Mounting is horizontal, vertical or underhung. Operation is by swing handle, worm gear or motor operator.

Can it include an interrupter or grounding switch?

Yes. Vacuum or SF6 interrupters and a built-on grounding switch are available options, along with a key interlock system.

Is there an option for icy conditions?

Yes. An optional ice hood prevents ice buildup on the contacts.

Can it be used in retrofit installations?

EMSPEC lists retrofit work as an application, and the base has field-adjustable mounting provisions.

How do I know the switch is fully closed?

The closed position can be verified from the ground.

What standards and BIL ratings apply?

The product page does not list them. Ask EMSPEC or Powertech for the ratings and standards that apply to the model you need.

Where can you get the EMSPEC vertical break switch?

For questions or a quote, contact Powertech Associates and UPSC at info@powertech-upsc.com or (860) 678-8772. Send us your voltage, current, mounting, operator and interrupter requirements and we can help scope it.

Sources

• EMSPEC: Vertical Break Switch