Second quarter revenues increased 42% year-over-year to $603 million compared to our guidance range of $535 million to $550 million.
Organic growth is a key priority, and revenues increased 28% year-over-year on an organic basis.
Incoming order rates were strong during the quarter, increasing 74% year-over-year and 18% sequentially.
This resulted in a healthy book-to-bill ratio of 1.19 times.
EBITDA increased 90% year-over-year to $93 million.
EBITDA margins expanded 390 basis points from 11.6% in the year-ago period to 15.5%.
EPS increased 163% year-over-year to $1.21 compared to $0.46 in the year-ago period and our guidance range of $0.88 to $0.98.
For the full year 2021, we are increasing the high end of our revenue and earnings per share guidance ranges by 170 and $0.77 respectively.
Industrial Solutions revenues increased 32% organically with broad-based strength in each of our primary market verticals and regions.
During the second quarter, we received a $6 million award for a project with a large investor-owned utility in the United States for the implementation of a critical communications network.
These products previously contributed approximately $15 million in annual revenue, with an immaterial contribution to EBITDA and cash flow, and we were pleased with the $11 million sales price.
Enterprise Solutions revenues increased 23% year-over-year on an organic basis in the second quarter.
Within the segment, revenues in broadband and 5G increased 13% organically.
Broadband fiber revenues increased 28% organically year-to-date in 2021 after similar growth in 2020.
Revenues in smart buildings increased 36% year-over-year on an organic basis, substantially exceeding our expectations.
Revenues were $603 million in the quarter, increasing $178 million or 42% from $425 million in the second quarter of 2020.
Revenues increased 28% organically compared to the prior year and 9% sequentially.
Incoming order rates were also very strong during the quarter, increasing 74% year-over-year and 18% sequentially.
This resulted in a book-to-bill ratio of 1.19 times, including 1.22 times in Industrial Solutions and 1.16 times in Enterprise Solutions.
Gross profit margins in the quarter were 35.7%, increasing 30 basis points compared to 35.4% in the year-ago period.
In the second quarter, the pass-through of higher copper prices had an unfavorable impact of 320 basis points.
Excluding the impact of this pass-through, gross profit margins would have increased 350 basis points year-over-year.
EBITDA was $93 million, increasing $44 million or 90% compared to $49 million in the prior year period.
EBITDA margins were 15.5%, increasing 390 basis points compared to 11.6% in the year ago period.
Excluding the impact of higher copper pass through pricing, EBITDA margins would have increased 510 basis points year-over-year, demonstrating solid operating leverage on higher volumes.
At current foreign exchange rates, we expect interest expense to be approximately $62 million in 2021.
Our effective tax rate was 18.2% in the second quarter as we benefited from incremental discrete tax planning items.
We expect an effective tax rate of approximately 19% in the third quarter and 19.5% for the full year 2021.
Net income in the quarter was $55 million compared to $20 million in the prior year period.
Earnings per share was $1.21 compared to $0.46 in the second quarter of 2020.
The Industrial Solutions segment generated revenues of $335 million in the quarter, increasing 51% from $221 million in the second quarter of 2020.
Segment revenues increased 32% organically.
Revenues in industrial automation, our largest market, increased 36% year-over-year on an organic basis, with broad-based strength across each of our primary market verticals.
Non-renewal bookings increased 12% year-over-year in the first half of the year.
Industrial Solutions segment EBITDA margins were 16.9% in the quarter, increasing 500 basis points compared to 11.9% in the year-ago period.
The Enterprise Solutions segment generated revenues of $268 million during the quarter, increasing 32% from $203 million in the second quarter of 2020.
Segment revenues increased 23% organically.
Revenues in broadband and 5G increased 13% year-over-year on an organic basis.
This supports continued robust growth in our fiber optic products, which increased 21% organically in the second quarter.
Revenues in the smart buildings market increased 36% year-over-year on an organic basis, substantially exceeding our expectations.
Enterprise Solutions segment EBITDA margins were 13.2% in the quarter, increasing 230 basis points compared to 10.9% in the prior year period.
Our cash and cash equivalent balance at the end of the second quarter was $423 million compared to $371 million in the prior quarter and $360 million in the prior year period.
Working capital turns were 7.6 compared to 6.7 in the prior quarter and 5.5 in the prior year period.
Days sales outstanding of 53 days compared to 54 in the prior quarter and 60 in the prior year period.
Inventory turns were 5.1 compared to five in the prior quarter and 4.5 in the prior year, and our financial leverage improved significantly during the quarter.
Net leverage was 3.3 times net debt-to-EBITDA at the end of the second quarter compared to four times in the prior quarter.
Specifically, in July, we issued EUR300 million in new 10-year notes maturing in 2031.
The interest rate on these notes is 3.375%, which matches the lowest interest rate on 10-year notes in the history of the company.
Following the redemption, our debt maturities will range from 2026 to 2031, with an average interest rate of 3.6%.
Cash flow from operations in the second quarter was $68 million compared to $40 million in the prior year period.
Net capital expenditures were $16 million for the quarter compared to $20 million in the prior year period.
And finally, free cash flow in the quarter was $52 million compared to $20 million in the prior year period.
We are pleased with the year-to-date free cash flow generation, which is approximately $50 million better than the first half of 2020.
We anticipate third quarter 2021 revenues of $590 million to $605 million and earnings per share of $1.11 to $1.21.
For the full year 2021, we now expect revenues of $2.32 billion to $2.35 billion compared to prior guidance of $2.13 billion to $2.18 billion.
This $170 million increase to the high end of our guidance range includes approximately $140 million from improved operational performance and $30 million from higher copper prices and current foreign exchange rates.
Our revised full year guidance implies consolidated organic growth of approximately 15% to 17% compared to our prior expectation of 6% to 9%.
We now expect full year 2021 earnings per share to be $4.37 to $4.57 compared to prior guidance of $3.50 to $3.80.
Our revised guidance for the full year 2021 implies total revenue growth of 25% to 26% and earnings per share growth of 59% to 66%.
We expect interest expense of approximately $62 million and an effective tax rate of 19.5% for the full year 2021.

Summary:
EPS increased 163% year-over-year to $1.21 compared to $0.46 in the year-ago period and our guidance range of $0.88 to $0.98.
Earnings per share was $1.21 compared to $0.46 in the second quarter of 2020.
We anticipate third quarter 2021 revenues of $590 million to $605 million and earnings per share of $1.11 to $1.21.