Westinghouse Type W MCC Buckets: Legacy Equipment Guide

Westinghouse Type W motor control centers represent a significant installed base of legacy MCC equipment across North America. Although Westinghouse Electric Corporation was acquired by Eaton in 1994 (low-voltage division), thousands of Type W MCCs remain in daily operation. This guide helps you identify, maintain, and source replacements for these durable but aging systems.

History

Westinghouse was a pioneer in motor control technology. The Type W MCC was introduced in the 1960s and produced through the mid-1990s when Eaton acquired the product line. During its production run, the Type W became one of the most widely installed MCCs in industrial and utility applications.

After the Eaton acquisition:

Westinghouse Type W production ceased
Eaton's Freedom series became the replacement platform
Many Type W components became increasingly difficult to source
Aftermarket manufacturers like MCC Depot stepped in to fill the replacement gap

Identifying Type W MCCs

Nameplate

Look for "Westinghouse" manufacturer name and "Type W" or "W" designation on the MCC nameplate. The nameplate is typically on the main incoming section.

Visual Characteristics

Type W MCCs have distinctive features:

Door style: Unique Westinghouse door handle and latch design
Section construction: Painted steel with specific Westinghouse fastener patterns
Color: Often medium gray or ANSI 61 gray (though repainting makes this unreliable)
Bucket latch: Specific to Westinghouse design

Stab Configuration

Type W stabs have a unique design that is not compatible with any other MCC manufacturer:

Proprietary contact finger geometry
Specific bus bar engagement pattern
Available in various amperage ratings

Specifications

Physical Dimensions

Section width: 20 inches
Section height: 90 inches (standard)
Section depth: 20 inches
Bucket heights: 6", 12", 18", 24", 36", 48"

Electrical Ratings

Voltage: 600V AC
Horizontal bus: 600A to 2500A (typical)
Vertical bus: 300A (standard)
Short-circuit rating: Varies by vintage and configuration

Legacy Component Challenges

The biggest challenge with Type W MCCs is sourcing replacement components. Many original Westinghouse components are discontinued:

Circuit Breakers

Westinghouse FB, HFB series: Discontinued. Some aftermarket availability.
Westinghouse KDB series: Very limited availability.
Solution: Cross-reference to current Eaton breakers that fit the same mounting pattern. In many cases, an Eaton FD or HFD frame breaker can replace a Westinghouse breaker with minor modification.

Contactors

Westinghouse A200 series: These were actually adopted by Eaton and continued in production. Current Eaton A200 contactors are often compatible with Type W buckets.
Westinghouse Size 00-6 starters: NEMA-rated starters that use standard mounting patterns.

Overload Relays

Westinghouse thermal overloads: Discontinued heater elements can be difficult to source.
Solution: Upgrade to electronic overload relays that offer adjustable protection ranges, eliminating the need for specific heater elements.

Control Transformers

Westinghouse machine tool transformers: Standard VA ratings and voltage ratios. Current-production transformers from any manufacturer can replace these as long as the specifications match.

Common Type W Issues

1. Age-Related Insulation Breakdown

Type W MCCs can be 30-60 years old. Wiring insulation degrades over time:

Cracking and flaking of wire insulation
Brittle insulation on control transformer windings
Degraded bus bar insulation

Action: Inspect all wiring carefully during maintenance. Replace any wires with cracked or deteriorated insulation.

2. Obsolete Components

Finding exact replacement parts is increasingly difficult:

Breakers may be discontinued with no drop-in replacement
Overload relay heater elements are unavailable
Door-mounted devices (pushbuttons, lights) may use obsolete mounting patterns

Action: Work with an aftermarket supplier like MCC Depot that can build replacement buckets with current-production components that fit the Type W form factor.

3. Stab Degradation

After decades of service, stab connections may have:

Significant oxidation on contact surfaces
Reduced spring tension
Evidence of overheating (discoloration)
Physical wear from repeated insertion/removal

Action: Inspect and refurbish stabs when possible. Replace stab assemblies when degradation is advanced.

4. Bus Bar Deterioration

The horizontal and vertical bus bars in very old Type W MCCs may show:

Oxidation at bolted connections
Loose connections from thermal cycling
Surface pitting at stab contact points

Action: Retorque all bus connections during scheduled outages. Clean and treat bus bar surfaces. Consider infrared thermographic surveys to identify hot spots.

Replacement Strategy

Option 1: Replace Individual Buckets

The most common approach. Replace failed or obsolete buckets one at a time with aftermarket units built to fit the Type W form factor:

New components and wiring
Correct Type W stab configuration
Modern overload protection
Maintains the existing MCC structure

Option 2: Complete MCC Replacement

If the MCC structure itself is deteriorated (severe corrosion, bus bar damage, structural issues), a complete replacement may be more cost-effective:

New MCC with current technology
Opportunity to upgrade to arc-resistant design
New bus system with full warranty
Higher upfront cost but lower long-term maintenance

Option 3: Retrofit Program

Systematically replace all buckets over a planned schedule:

Prioritize critical motors and highest-risk buckets
Spread the cost over multiple budget cycles
Maintain production throughout the upgrade process

MCC Depot Type W Solutions

MCC Depot specializes in building replacement buckets for legacy MCCs including Westinghouse Type W. We can:

Match the Type W stab configuration exactly
Build with new, current-production components
Accommodate any bucket height and configuration
Deliver in 3-5 business days for standard configurations

Visit our retrofits page for more information on our legacy MCC solutions.

Call 307-442-0382 or email sales@mccdepot.com with your Type W MCC details.