When a terrorist bomb exploded underneath the World Trade Center on Feb. 26, 1993, it ripped out a three-story crater, shut down most of the building's electrical power, and caused $500 million in structural damage. The first international terrorist attack on U.S. soil, the bombing claimed the lives of six people, injured more than 1000, and forever changed the level of security at the landmark complex.

E-J Electric Installation Co., the country's oldest independent electrical contractor, won a $28 million contract in 1996 to tighten security at the World Trade Center. The Long Island City, N.Y.-based contractor installed 2 million ft of fiber optic cable, hundreds of security cameras, access control, and 110 turnstiles (including systems integration).The parking garage also became restricted after a terrorist drove a van containing a bomb into the underground parking garage in 1993.

“There's no public parking down there anymore after the bombing,” says E-J Vice President Jim Usher, who has been on the project since October 1996. “It's for the Port Authority and the tenants. We're much more concerned with below grade in terms of security than we are up here.”

The World Trade Center sits on top of the largest indoor mall in New York City as well as a major regional transportation hub.

“Thousands of people come through here every day,” says Usher. “There's another whole city below this complex.”

To control the flow of people, a total of 110 turnstiles, which were hand built on the job, restrict access to the World Trade Center complex, says Usher.

“This used to be unlimited access,” says Usher. “Now there are turnstiles that go all the way around in a circle. Where there isn't a turnstile, there's a glass rail.”

The 55,000 tenants in the complex have a permanent identification card they lay on top of a scanner, while visitors are issued a temporary, swipe-through card. While a tenant can use a card for an entire year, some visitors only get a card that's good for 20 min.

“If a visitor is just here to see someone, they're good for a day and that is it,” says Usher. “If you're a courier or a pizza delivery guy, you would only get a pass that would be good for 20 min. You would have to go through the turnstile, go upstairs, and deliver the pizza. Once you come back out, you can't come back in.”

Visitors also only have access to certain buildings in the complex.

“If you came to visit your brother on the 100th floor, you can only go in Tower 1 if that is where your brother is,” says Augustine Calabro, former general foreman for the World Trade Center. “You couldn't go in Tower 2. It's simple, but elaborate.”

Smile, you're on camera. Hidden cameras in the ceilings and light fixtures record anything and everything that goes on in the complex.

“Up here in the ceiling, in the domes, there are all hidden cameras,” Usher says. “The lobbies are covered by closed-circuit television.”

When visitors approach the desk to request a badge, they have to show a photo I.D. and give their name. The operators will then call the tenant and request permission to issue a visitor's badge. At that time, a strategically placed video camera takes a photo of the visitor.

“Visitors are being photographed and their images are permanently stored,” Usher says. “We can track every card — what turnstile it went through and what time it went through. So if there is a problem, we can go back and pull their image back up from storage and print it. We have no idea when anybody leaves here, but we know when they enter.”

The buildings surround a five-acre plaza, which has hidden security cameras. Cameras on the rooftop also monitor every street that borders the property.

“This entire complex and plaza are under closed-circuit television and constant surveillance, day and night,” Usher says. “There's cameras all over the place inside and out.”

Hundreds of cameras videotape the activity both inside and outside of the complex. The videotapes are archived for reference. The security operators can videotape the entire plaza or zoom in on a suspicious individual.

Americans want both security and convenience, which poses a challenge in New York, Usher says. Rather than jumping on an elevator and going to their desired floor of the center, visitors have to wait in line, get a visitor's badge, and swipe it through the turnstile.

“New Yorkers are such fast-paced people,” Usher says. “Then you add to the fact that they're paying more rent per square foot than anywhere in the world. They would say: ‘Wait a minute. My visitor had to wait in line for two minutes. I'm paying millions of dollars in rent.’ So it's trying to design a security system that's user-friendly, tenant-friendly, yet still gives some security. That's the key.”

Twin towers. To ensure top security and reliability, the 1380-ft, 110-story Twin Towers both have command centers.

“It's totally redundant security,” Usher says. “The theory is that if you had a bomb and you took one of the command centers out, everything is totally redundant so the other command center would pick up. If the computers fail, they automatically switch over to other computers at another location.”

The security system was designed as a redundant loop, Calabro says.

“You had a network that went up one building from Source A and returned to Source B,” Calabro says. “At any time, if the network was interrupted, you would not lose the system because it could be fed simultaneously from both sides.”

E-J installed miles of fiber optic cable for the redundant system.

“This is the largest installation of fiber optic cable in the world, Usher says. “More fiber has run through this complex in the last two years than any other system.”

The contractor worked all four towers at one time from the B6 level to the 110th floor to install the cabling for the security system.

“We peaked at about 60 electricians,” Calabro says. “We had smaller crews with more supervision because the men were spread throughout the complex.”

Built in the early 1970s, the World Trade Center is spread out across 16 acres. Because of the large scope of the retrofit project, it became a challenge for the electricians to move their equipment, Calabro says.

“Getting from point A to point B was a job in itself,” Calabro says. “We went to Nextels to improve communication.”

The team also had to work nights to finish the job.

“Most of the work we had to do was in occupied tenant spaces where we had to run up the risers,” Calabro says. “Tenants don't want anyone disturbing their normal operation, so a lot of the work had to be done off hours. We had a lot of late nights and night crews.”

While they were working on the security, E-J picked up some other jobs, such as working on the fire-alarm system and setting generators on the top of Tower 5 to feed the Twin Towers with emergency power.

“The Trade Center was never designed for the amount of emergency power necessary for all those trading floors they have there,” Calabro says. “Tenants would come in and need emergency power, and it was not available.”

To solve that problem, E-J Electric set four generators on the roof of Tower 5, which was nine stories, as opposed to the 110-story Towers 1 and 2. E-J then ran high-voltage feeder cable to Towers 1, 2, 4, and 5, installed three substations, and distributed power to the tenants.

“We pulled 6000 ft of high-voltage feeder cable from the roof of Tower 5, through the building, down through the concourse, through the parking garages and to the roof of Tower 1 and 2,” Calabro says.

Calabro says E-J is fortunate to have a maintenance contract along with some other jobs for the World Trade Center.

“Security was the original contract that got us in the building and then we were fortunate enough to get these other jobs,” Calabro says. “The generator job is up to about $6.5 million right now.”

Calabro, who is now supervising the work at Madame Tussaud's wax museum in Times Square, says he is proud to have worked with the security on the World Trade Center.

“I would like to believe that it was an important job in the company,” he says. “We have been there for four years. That's a challenge in itself. Contractors come and go in that building.”

Usher says E-J plans to continue to take on projects at the World Trade Center.

“We have a maintenance contract, so we'll be here forever,” he says. “It's going to keep growing and changing.”

Fischbach is a staff writer for CEE News Magazine.

World Trade Center Stats
  • The bombing claimed the lives of six people, injured more than 1000, and caused $500 million in damage. After the bombing, the owner tightened security. Now, more than 300 security guards secure the complex, hundreds of cameras provide surveillance, and 300 doors are monitored and secured.

  • A tenant I.D. and visitor pass program is in place. An electronic access-control system using proximity photo I.D. cards for building tenant/employees helps streamline tenant and visitor access. Visitors receive photo I.D. swipe cards for turnstile access.

  • Current standard tenant power capacity is 6W (up to 10W) per usable square foot depending on location. The World Trade Center's electricity supply is segmented for greater reliability and safety. Eight dedicated 13.8kV feeders divide into 23 building substations. On-floor electrical distribution is routed via at least two electrical closets per floor, each with separate high- and low-voltage bus ducts for tenant-dedicated use.

  • The World Trade Center has multimode fiber optic cables that loop through both towers and the plaza buildings and are accessible to every floor.

  • 55,000 people work in the World Trade Center Complex.

  • More than 1.2 million cubic yards of earth and rock were excavated for the World Trade Center.

  • Four generators on the roof of the World Trade Center (8.8MW capacity) provide standby power to tenants throughout the complex.

  • More than 200,000 tons of steel was used in constructing the complex.

  • The 425,000 cubic yards of concrete used in building the World Trade Center is enough to build a 5-ft sidewalk from New York City to Washington, D.C.

  • 3500 workers were on the site daily during peak periods of construction.

  • The World Trade Center's refrigeration plant is the largest in the world with 60,000 tons of cooling capacity.

  • There are 239 elevators and 71 escalators in the four buildings operated by the Port Authority at the complex. The Sky Lobby express elevators are capable of carrying 55 people, a 10,000-lb capacity. Express elevators can travel at speeds of up to 27 ft per second.

  • The complex is situated on a 16-acre site and consists of seven buildings with 12 million sq ft. All are constructed around the five-acre Austin J. Tobin Plaza.

  • The World Trade Center sits atop the largest indoor mall in New York City and a major regional transportation hub.

Source: Port Authority of New York and New Jersey Web site and Jim Usher and Augustine Calabro of E-J Electric Installation Co.