As a result of the recent weather, those of us in South Carolina have gained a renewed appreciation of the damage that can result from flooding. Even a few inches of flood water can result in property damage and a loss of services in addition to the immediate risk of physical harm.
Flood damage to electrical equipment can manifest itself either immediately or progressively over time. Flood waters are not pure and often contain chemical or biological contaminants that can exacerbate water damage.
Short circuits and improper operation are the most common forms of immediate damage from flood waters, while corrosion and high resistance connections are forms of damage that progress over time.
Flood damage to electrical equipment can be difficult to judge – the equipment may appear undamaged and operate normally at first but could fail prematurely years after the event. Investigative steps to evaluate electrical equipment that has been in a flooded area include the determination of whether:
– The equipment was within the flood elevation.
– The equipment was energized at the time of the flood.
– The equipment was open, watertight, or waterproof.
– There is any residual water or sediment inside cabinets or enclosures.
– Paper labels and diagrams are water damaged.
– There is new metal corrosion on a visual or microscopic level.
– Cut ends of waterproof electrical cables were submerged.
– The equipment had pre-existing damage.
– The equipment meets current codes or must be upgraded to current codes
The National Electrical Manufacturer’s Association (NEMA) has published “Evaluating Water-Damaged Electrical Equipment” to provide guidance on whether electrical equipment can be repaired or must be replaced after flooding. The publication provides a simple table listing electrical equipment types and classifying them as either “Replace equipment” or “May be reconditioned (contact the manufacturer)”. The publication also provides rationales for the recommended actions.
Two caveats regarding the NEMA publication are that it provides only for generic equipment types and only for repairs/reconditioning by the manufacturer or in consultation with the manufacturer.
Often manufacturers are not identifiable, are no longer in business, or no longer produce the equipment model. Manufacturers also can have unacceptably long lead times for replacement equipment or repairs, particularly after a large flooding event. There are competent service companies available to repair most types of electrical equipment, both at the site of a flood and at their facilities.
John Phillips, senior consulting engineer at Warren, has more than 30 years of crane and heavy equipment experience and more than 19 years of experience in forensic engineering. A licensed professional engineer in South Carolina, North Carolina, Georgia, Louisiana and Ohio, he’s NCEES registered both as a model engineer and with The United States Council for International Engineering Practice, USCIEP. John has designed crane systems, supervised installation, tested and certified lifting equipment even serving as a project engineer for maintenance and certification of nuclear weapon lifting and handling systems. John is a certified fire and explosion investigator and fire and explosion investigator instructor by the National Association of Fire Investigators. John is a member of the American Society of Materials and American Society of Testing and Materials, as well as a voting member of ASTM Ships & Marine Forensic Sciences, Forensic Engineering, and Performance of Buildings committees.