Eliminating the jolt from lightning strikes

In June 1993, a lightning storm passed over the Public safety Answering Point (PSAP) located at the Deerfield police Department, Deerfield, Ill., and within seconds of one bright lightning flash, Deputy Chief Gary Stryker realized he had a problem.

All the E 9-1-1 answering stations, including the police computer system communicating on an IBM token ring network, were rendered inoperative. As a result of the lightning strike, the Deerfield Police Department could no longer monitor the many alarm systems wired back from local businesses, and it became clear that the problem could not be fixed in a matter of minutes. As a result, the decision was made to switch all E 9-1-1 operations to the emergency atternate site, which can be an expensive decision. The clean-up process took time, a full three days in fact, and the cost to replace damaged hardware exceeded $100,000. And that 1993 lightning strike was the department’s third. Statistics show that this is not an unusual or extreme example of lightning damage, which can pose major problems for most electronic equipment, particularly networked equipment.

Because of the radio antenna mast, E 9-1-1 sites are often more vulnerable than the average commercial electronic installation. Additionally, preventive action is often hampered by misinformation. Deerfield’s solution to its PSAP lightning problem was to install Atlantic Scientific’s Emergency Management Systems Protection system. For instance, secondary telephone suppressors were installed on all incoming telephone lines because they achieve better control of transients than the crude gas discharge devices normally installed where the line enters the site, and a main panel surge protection device was installed to block lightning surge currents at the AC power service entrance. The IBM server and terminals were each protected from AC-induced transients as well as transients on communication lines using a modular surge protection system. Power and communication links to both the E 9-1-1 system and the taped recorder system were also protected.

Two lightning seasons later, no problems have been reported on protected equipment at the police department, particularly impressive considering the proximity of several lightning storms. In fact, during one close storm, extensive damage was reported to the systems in other nearby buildings, but the police department experienced no problems.