The Largest Independent Electrical-Mechanical Sales and Service Company in the Northeast
Case History:
Fire and explosion from water damage

A Northwest NJ manufacturing plant was coping with one of those intense Jersey downpours, a couple of inches an hour. It was a little after 6 am when the water from the downpour appeared to shourt out the electrical system's main feeder. The transformer exploded, sending flaming oil into the switchgear. In a milli-second it was game on.

Longo has handled just about every type of electrical crisis, disaster, or catastrophe. The sources for these range from raccoons paying the ultimate price when shorting out equipment to old unmaintained equipment, to makeshift wiring, and Mother Nature. The causes of these events can be interesting, but Longo, which comes in after the fact is concerned with how to quickly get the equipment up and running again, whether by repair or replacement.

The Incident
Longo was contacted at 8:30am the day of the explosion. Talking to the customer it was quickly evident that the scope of the damage would require a swift and concentrated effort. Within 30 minutes a Longo Field Service Technician was on site evaluating the scope of the damage. A triage of the facility and the damage would consist of what is the extent of the damage, what is involved in getting the customer back up and running until repairs and new equipment can be installed, and how to manage this effectively.

The Assessment
The equipment that blew up was a 3500 KVA transformer, with a primary voltage of 12,470 and a secondary voltage of 480. Initial observations indicated the low voltage buss going into the building failed causing a bolted short circuit on the 480 volt side. The cause of the buss failure was assumed to be water intrusion into the buss duct resulting in a short circuit This led to very high currents in the transformer secondary (480 volts) which caused it to heat rapidly and fail violently. A rupture of the transformer tank spilled its oil which caught fire. Unlike many of these cases, the equipment in this situation seems to have been maintained and functioning prior to the incident The customer also had functioning safety equipment in the form of sprinklers and an automatic fire door.

The Response
Within 4 hours 18 Longo Field Service Technicians were on sit£. While some were isolating the damaged equipment from the company's electrical system, others were testing the existing electrical system and preparing to connect auxiliary power to the remaining power system. This team was also assessing what materials would be needed to reestablish power to the facility. Contact with our procurement personnel made sure the delivery of the materials would enable the team to maintain its pace. Our switchgear specialist was on site reviewing the damage, possible causes, and developing an estimate to supply and reinstall new equipment to replace the fire damaged units. Immediately after the initial contact Longo made arrangements for two emergency generator trailer's to be on the site within 6 hours two generators, 4MW of emergency power, were on site and the technicians were laying out the cables and preparing to re-establish power to the company. Longo management clearly outlined our procedures and actions with the customer. Since the pace of activity would be intense, communication with the customer's facility team was essentially constant

The Repair
The generators supplied 480 volts to most of the building via cables that were routed, suspended and connected to the remaining electrical systems that were determined to be still functional through electrical testing. In other words, the generator power was bypassing the damaged areas. They were like huge extension cords supplying power at points some distance from the destroyed switchgear. Much of the existing overhead buss duct was either destroyed or damaged enough to be unusable. To replace this amount of buss duct would have seriously delayed this project and seriously impacted our customer's bottom line. Replacing the buss with cables is something Longo was very familiar with and able to do with exceptional speed There was approximately 22,500 feet of conduit and cable installed replacing the 30 year old buss duct A new 4000A switchboard was manufactured in one week and a new transformer was installed All this work was completed within 30 days minimizing the cost of the emergency generators and providing the customer with peace of mind

973-537-0400          One Harry Shupe Boulevard          Wharton, NJ 07885          elongo.com