Five years ago we conducted an arc flash evaluation on the west coast for one of the largest food factories (of its type) in the world. Almost a million square feet and nine main transformers supplying up to 30MVA of power!
Four of the nine main transformers fed to switchgears all located in the same room. The final report we issued identified large potential incident energies on each of the four switchgear. Not only was the main feed a high hazard but so was the entire switchgear fed off the main. The settings on each of the main devices were turned all the way up – there was no arc flash protection!
Rozel engineers look at every setting during an evaluation – if you have high potential energy, we’ll ask, “how can we reduce this?”. In this facility’s case, we were able to find a remedy. Our recommendation was to change a setting on each of the four main breakers, lowering the arc flash boundary from over 40 feet to under 2 feet. We not only helped them lower available incident energy but we also confirmed that these settings would not affect running conditions of their downstream equipment. Imagine the damage an arc flash could do if it could cause second degree burns 40 feet away! People could be injured and equipment would be destroyed, shutting down production for a long time to come. In the case of this facility, a catastrophic fault on one switchgear would potentially take down four of the nine main switchgears.
Our engineers make recommendations after every evaluation which can lower hazards. These recommendations are followed… and then, well… fingers crossed, nothing ever happens. Hopefully we never have to find out if our recommendations worked. However in the case of this factory, we did find out. A recent modification required new equipment be installed from a sub breaker on one of the four main switchgear mentioned above, in the same room as the switchgear, in fact, right in the middle of the room. Equipment was faulty during install and it was not discovered until it was time to try it out. A qualified worker wearing appropriate PPE turned the breaker on and…. the breaker tripped. Further investigation discovered there was a live phase short to ground. Minimal damage was caused, equipment less than 2 feet away showed burn marks, but nothing further.
Catastrophe avoided. It is very likely that without following our recommendations that the worker could have been very badly injured and equipment down for a long time to come. The simple setting change not only paid for our customer’s arc flash evaluation expense but it reduced downtime and most importantly allowed that worker to go home at night.
Many times we take our electrical equipment for granted but when it fails it can take down a large portion of a facility. The Atlanta airport is a good example of how one important room can slow down normal operations: link. Are you sure that your equipment is set properly?