I have had the opportunity in the past of determining the extent of damage and providing recommendations for corrections to residences damaged by lightning and several that were incidences of high voltage damage to residences caused the the High voltage line falling across the secondary service drop serving the residence.

In addition I have investigated lightning damage to commercial and industrial facilities, usually to roof top equipment, towers and high structures.

The net result is usually always the same. There will be three types of damage that usually results from higher than normal voltage entering the facility and in some cases phyical damage to the structure itself.

Aside from the structural physical damage, your tasks will be: 1. Identify the point or points of entry of the lightning or high voltage to the residence. The most likely points are: a. Main electrical service entrance fron the utility. b. Telephone service point of entry. c. Cable TV service point of entry. d. Free standing antennas for TV, radio or satellite e. Domestic water service point of entry. f. Gas piping from street or tank. f. Any overhead or underground electric feeder lines to outbuildings or garages. 2. To identify the extent of damage to the electrical system, its components and the appliances. 3. Define and identify the wiring, components and appliances that need to be replaced and those that are safe to remain.

4. The following three basic types of damage at a minimum should be investigated and tests conducted to confirm, rule out and determine the extent of damage. a. Arc and/or flash damage to cables, panels and electrical system components. which leaves conductive residue, tracking and in some cases holes in the cables or enclosures. b. Insulation overvoltage stress damage to cables, electrical panels, disconnects and breakers. c. Internal damage to the appliances, light fixures and components that were connected or plugged into the system at the time of the lightning or high voltage event. (Note damage can occur anytime a component is connected even if not running or on at the time.)

At a minimum the following should be performed by a qualified electrician or certified testing technician. 1. Conduct a visual inspection of all exposed wiring, cables, piping, ground rods and water pipe ground connections for evidence of arcing or heat damage. Pay particilar attention to any termination points and where cables or wires pass over or near other pipes or heat ducts. Lightning induced voltages will arc over to other items with a path to ground causing visible arc damage to both at that point. 2. Open and visually inspect for arc and flash damage in all Electrical panels, sub panels, meter enclosures and feeder junction boxes to all appliances such as ranges, stoves, surface units, dryers, washing machines, Air Conditioning units out side and inside including the ac/blower & heating units. 3. While all of the above are open, systematicly unplug and/or disconnect the terminations between the appliances and the feeders after turning off the power to each and verifying that each has been deenergized. 4. Once isolated all feeder cables should have insulation resistance tests performed on each conductor with respect to ground and to each other. The applied potential should be 500 volts DC for 300 volt rated cable and 1000 volts Dc for 600 volt rated cable. The test duration should be for one minute. Minimum test values should be in accordance with manufacturers published values, comparable with new cable of equal size, type and length but not less than TWO megohms. 5. The branch circuit wiring feeding recepticle outlets, and lighting fixtures should be tested in the same manner and levels as stated above in item #4. Before preceeding with testing, verify the following: a. Circuits are de-energized, and verified as having no voltage present. b. Circuits are isolated by opening each breaker, and/or disconnect. c. Unplug all appliances and utilization equipment from all outlets on the premise. d. Disconnect all ceiling fans and remove all fixture lamps and bulbs. 6. After deenergizing and verifying no voltage is present, perform same tests on all electrical panels, sub panels, breakers and disconnects. 7. After deenergizing and verifying no voltage or other hazard exists perform insulation resistance integrity tests and/or leakage tests on each appliance individually at the voltage level, duration and by the method specified by each manufacturer. 8. Replace all wiring cables, panels, breakers, dicconnects, fixtures, components and appliances that do not past the visual inspections and testing described above and in accordance with the manufacturers instructions. 9. Require that a permit is secured from the local authority by the persons performing the testing prior to the beginning of any testing and verifications. 10. Request a copy of the completed permit bearing the signature of the approving local authority following the completition of the work. Forward this to the home insurance policy carrier.

11. Further consideration should be given to making a recommendation(s) to the home owner for cetain preventive measures against the possibility of future occurances or events of the same type encountered. The recommendations as approiate may include the following: a. Upgrades to the system grounding and bonding of all metal components to lessen the damage and hazard. b. Installation of Transient Voltage Surge Suppression (TVSS) devices at the main electrical service entrance, telephone service and cable TV service entrances, any out building electrical panels and on any high value electronic devices, TV, audio and recording equipment. c. Ask the utility to verify the integrity of ground connections and any surge arrestors at their pole or undergroung service transformer serving the residence.

Note: Each event or occurance of damage caused by lightning induced or other abnormal source of high voltage will be different with respect to the many different types of home constructions, proximity to other structures, trees, towers and the configuration of each homes electrical system as well as the utility system configuration and protective devices. The diagnostics of such damage and recommendations for corrections should be performed only by qualified and experienced professionals.

Thank you for the opportunity to post these comments. I sincerely hope they will be of some value to those with the need.

Larry LeSueur CPQ, CBCP Barrett Woodyard & Associates, Inc. Electrical and Mechanical Consulting Engineers. 3495 Holcomb Bridge Rd. Norcross, Ga. 30092 770-810-8800 llesueur@barrettwoodyard.com