1. WESCO Richard Heyse, Vice President & Chief Financial Officer
WESCO Distribution, Inc.

2. Safe Harbor Statement
Note: All statements made herein that are not historical facts should be considered as “forward-looking statements” within the meaning of the Private Securities Litigation Act of Such statements involve known and unknown risks, uncertainties and other factors that may cause actual results to differ materially. Such risks, uncertainties and other factors include, but are not limited to, debt level, changes in general economic conditions, fluctuations in interest rates, increases in raw materials and labor costs, levels of competition and other factors described in detail in Form 10-K for WESCO International, Inc. for the year ended December 31, 2008 and any subsequent filings with the Securities & Exchange Commission. Any numerical or other representations in this presentation do not represent guidance by management and should not be construed as such. 2

3. WESCO Profile …an industry leader Extra-Effort Company Market Leader
Fortune 500 Company headquartered in Pittsburgh, PA
Over 6,300 employees including 2,300 sales personnel
380 Locations
Consistent strategy of market share growth:
Local market penetration with national programs
Accretive acquisitions
Operational excellence and LEAN
Leading Provider of:
National Account Programs
Integrated Supply Services
OEM Direct Materials and Services
Electric Utility Distribution Grid Solutions
Industry-leading cost structure
International operations and global sourcing capabilities
…an industry leader

4. Recession and Recovery
WESCO Evolution
Captive
Distribution Arm
of Westinghouse
Growth Strategy
Deployed
Recession and Recovery
Growth Accelerates
Severe Recession
LBO in 1994 by management and Clayton, Dublier & Rice
~$1.5 Billion in sales
~175 Branches in U.S. and Canada
~85% non-residential construction
Limited supply relationships other than Westinghouse
Sales grew to $3.7B
25 acquisitions
Expanded geographic footprint
Diversified end-markets and supplier base
Launched National Accounts Program
Launched Integrated Supply
Leveraged recapitalization 1998
IPO 1999
Severe industry downturn
High financial leverage
Suspended acquisition program
Strong free cash flow generation
Invested in sales and marketing programs
Launched LEAN
11 quarters of double digit sales growth
Sales grew to $6.1B
Invested in sales capacity expansion
Restarted acquisition program
7 acquisitions with $1.1 B sales
Product category expansion
Improved capital structure
Expanded marketing programs
Expanded LEAN
Significant cost reduction actions taken
Record free cash flow generation
Strengthened capital structure
Accelerating LEAN and extending to customers
International expansion
Investing in attractive growth verticals and geographies
…from captive distributor to global supply chain company

5. Market Opportunity
Large, Fragmented Market
Value of Distribution
$600B Construction, MRO, and OEM Markets
SUPPLIERS
CUSTOMERS
Sales
Marketing
Delivery
Service
Procurement
Warehousing
Logistics Management
MRO
Thousands of electrical and industrial product manufacturers
Over 10,000 electrical and industrial distributors
Top five distributors have 26% share of electrical distribution industry in U.S.
75+% of electrical products get to market through distribution
Continuing industry consolidation
Market Trends Benefit WESCO
Scale
Global sourcing
Value-creating solutions
Enhanced interdependence
…large, fragmented market with trends favorable to WESCO

6. WESCO – A Total Supply Chain Solutions Provider
Providing Broad Solutions to Large & Sophisticated Customers
Extensive products and services
Broad geographic coverage
Deep penetration into customer processes
Difficult to disintermediate
TODAY
TOMORROW
Market-Focused Branches
One WESCO
National Accounts
Global Accounts
LEAN and Integrated Supply
Complete Supply Chain
North American Centric
Global
…beyond electrical and traditional distribution

7. WESCO Market Mix and Product Portfolio
Markets and Customers
Products and Suppliers
Industrial
National Accounts
OEM
Integrated Supply
General Industry
Utility
Investor Owned
Public Power
Utility Contractors
Distribution Equipment
Wire, Cable & Conduit
Data Communication
13%
39%
16%
20%
12% 6%
11%
34%
Controls & Motors
39%
10%
Construction
Non-Residential
Data Communications
Pre-Fabricated Structures
Residential
CIG
Government
Education
Healthcare
General Supplies
Lighting & Controls
115,000 active customers
Majority of Fortune 500 companies are our customers
1,000,000 different products shipped annually, with 250,000 in stock
19,000 suppliers
Note: Percentages based on 2008 Sales
…diverse market, customer base, product lines, and suppliers

8. WESCO’s LEAN Journey …continuous improvement culture founded on LEAN
2003 and beyond
Customer Focus
LEAN:
The process of continuously eliminating waste across the business and value chain
Solution Categories
2003 launch
Initial focus on sales and warehousing
Centralized LEAN team
3,300+ Kaizen events
Enterprise-wide results
Leader in applying LEAN to supply chain
A competitive differentiator
Maintenance and
Production Support
Safety and Security
Green and Sustainability
…continuous improvement culture founded on LEAN

9. WESCO Today vs. Last Downturn
2009 YTD
Average
Industrial
40%
42%
Better End Market Diversification
Construction
25%
37%
(Seven Accretive Acquisitions
Utility
16%
15%
from )
Data Communications
13%
CIG 6%
Liquidity (millions)
$439
$176
Free Cash Flow (millions)
$280
$48
Free Cash Flow per Share (millions) $6 $1
Improved Operating Margins
4.0%
2.5%
LEAN Continuous Improvement
Launched Spring 2003
N/A
Experienced Management Team
Improved
Good
Solid Capital Structure
3.7x Leverage
7.2x Leverage
Note: Percentages based on 2008 Sales
…bigger, more diversified and more profitable with a stronger capital structure

10. WESCO Growth Strategy & Financial Objectives
Long Term Financial Objectives
Markets & Customers
Grow faster than the market plus acquisitions
Maintain industry-leading cost position
Expand operating profit
Provide superior return on invested capital
Generate strong operating cash flow through the cycle
Geography
Products & Suppliers
Target sales and marketing initiatives on attractive verticals
Sell complete set of products to all customers and service all their locations
Expand product and service portfolio and capabilities
Expand internationally
…focused on shareholder value creation

11. WESCO Growth Engines
Fortune 1000 focus
Sell all WESCO products and services
Capture new customers and expand with current customers
Maintain 100% National Account renewal rate
National Accounts and Integrated Supply
Leverage WESCO National Accounts position and geographic footprint
Data centers (data plus electrical products)
Targeted marketing initiatives (secure networking, security, etc.)
Data Communications
Electrical plus data communications
National Accounts model
Construction project management
LEAN applications to construction life cycle
EPCs and National Contractors
Expand scope of supply and value proposition to Investor Owned Utilities
Grow share in Public Power
Grow high voltage business serving transmission, substation and alternative energy markets
Utility
Aligned WESCO government resources into one team
Expanded government sales resources
Dedicated stimulus team established
Government
Use LEAN Value Creation toolset as a differentiator
Target major metropolitan markets with a density of healthcare institutions
Expand agreements with Group Purchasing Organizations and Integrated Delivery Networks
Healthcare and Education
Migrate from National to Global accounts
Invest and take share in Canada
Expand global footprint (China, Dubai, Australia)
Broaden geographic reach in Mexico
International
Invest and take share in lighting
Marketing and sales initiatives focused on lighting solutions
Dedicated region resources coupled with a focused set of lighting branches
Lighting
…aggressively targeting attractive opportunities during the downturn

12. Invest in WESCO Market leader with low business risk profile
Organic sales growth faster than market
Proven business model uniquely positioned in large, fragmented market
Operational excellence culture focused on LEAN
Solid ROIC performance and excellent cash conversion results
Proven acquirer in a consolidating industry
…strong company, excellent value creation opportunity