What Is a GOAB Switch?

Group-operated air-break switches, or GOABs, are three-phase disconnects that operate from a single shaft. They do the visible isolation work at substation entrances, transformer tie points, and bus-section breaks. They are simple, robust, and usually the last thing anyone thinks about until one will not open.

Where you find them

Walk into any utility substation and the most visible piece of equipment is usually a row of GOAB switches mounted high on the steel structure. Three phases, opening and closing in unison from a single mechanical operator at ground level connected through a vertical drive shaft and linkage.

Their job is isolation, not interruption. A GOAB opens after the load has been removed by an upstream breaker. The visible open gap, the air break itself, is the clearance that lets crews work safely on the de-energized side.

Three places they live: at the substation entrance ahead of the main bus, between transformer banks and the secondary bus, and at tie points between sub-buses. Same switch, three jobs.

The manufacturers you will see

Southern States dominates distribution and sub-transmission voltages in North America. The EV1, EV2, and EV3 series cover 15 kV through 230 kV. The EV2 in particular is the most installed GOAB across the southeastern United States.

Cleaveland/Price shows up at higher voltages and in vertical-break designs at transmission substations.

USCO makes a wide range of distribution-class GOABs.

Pascor and a handful of smaller manufacturers serve specific utility specifications and retrofits.

Most of these switches have been in service for 40 to 60 years. Either the original manufacturer no longer supports the design, or they were acquired and the product line was discontinued. Reverse-engineered replacement parts are the realistic path to keeping them running.

How they work

A standard three-phase GOAB has three identical blade-and-jaw assemblies on a horizontal frame. The blades pivot through bearing housings at each phase. A vertical drive shaft connects the assembly to a manual handle (or motorized operator) at ground level. Turning the handle drives a horizontal shaft across all three phases, opening or closing the blades together.

The current path runs from the line terminal, through the jaw contact, along the blade, through the pivot contact at the hub, to the load terminal. Every contact in that chain is a potential resistance and a potential heat source. The contact surfaces are silver-plated copper for low resistance and arc resistance.

Air-break clearances scale with voltage. A 15 kV GOAB has about 12 inches of clearance when open. A 138 kV GOAB has about 60 inches.

Why GOABs fail

Bearings seize first. The pivot bearings live outdoors for decades, accumulating moisture, dust, and salt-spray. Once they stiffen, the operator has to push harder to open the switch. That bends linkages and accelerates wear on everything else. Southern States EV2 bearings are the most common failure we see in southeastern utilities, and salt-laden coastal humidity makes it worse.

Contacts wear and develop hot spots. Open-and-close cycles under no-load are gentle, but silver plating still wears off over decades. Once the underlying copper is exposed it oxidizes, contact resistance climbs, and a thermal-imaging survey will pick up the hot spot before the switch fails.

Linkage gets sloppy. Connecting rods, universal joints, and operator gearing all accumulate slop. A GOAB that needs four or five handle revolutions to open instead of two is telling you the linkage has stretched.

Insulators deteriorate. Porcelain post insulators chip, crack, or accumulate contamination tracks. A flashover during operation can take a substation offline and badly damage the switch frame.

The Southern States EV2 in particular

The EV2 is so widely installed that its failure pattern deserves its own paragraph. The original design uses a mild steel shaft running in a bronze sleeve bushing. That works fine for most environments. In coastal Florida, salt-laden humidity drives accelerated corrosion of the steel shaft, and we see the bearing seize on a 10 to 15 year cycle.

Southern Switch & Contacts builds a stainless-shaft upgrade for the EV2 bearing. The kit replaces the steel shaft with 17-4 PH stainless, adds new brass lock nuts, and seals the assembly with Viton o-rings. It installs with no structural modification to the switch frame. The upgraded bearing comes back to like-new condition and outlasts the original.

For utilities running EV2 switches in coastal or industrial environments, the stainless upgrade during routine maintenance is a one-time fix that ends the recurring bearing-replacement work.

Running a GOAB maintenance program

Annual substation inspections (semi-annual for transmission) should always include the GOABs. The checklist is short: operator effort during a test cycle, blade alignment when fully closed, contact-finger spring tension, IR scan during the load survey, insulator visual, and linkage hardware torque.

Catching a stiff bearing or a hot contact during an inspection is a planned maintenance event. Finding it when the switch will not open during a crew callout is an outage.