How we produce an Arc Flash Analysis
Walk Through and Takeoff of Equipment
One of our Electrical Preventive Maintenance & Safety Consultants will meet with you on site to perform a walk through and takeoff of all the equipment required to have an arc flash label. Note many arc flash companies want to tell you 240-208-volt equipment 125 KVA or less do not require labels, * or will give you a number based on sq. ft. without visiting your site. Please beware of these companies, your analysis will most likely be incomplete.
*NFPA 70E requires that Electrical equipment such as switchboards, panelboards, industrial control panels, disconnects and motor controls that are likely to require examination, adjustment, servicing, or maintenance while energized shall be marked with an arc flash label.
Having engineered electrical installation drawings, one lines, previous arc flash drawings and any supporting data would be helpful and may reduce the cost of the arc flash analysis.
Contact the Power Company
We first contact the Power Company supplying your electrical service and acquire the available fault current at the power company’s transformer. Then we perform calculations to get the incident energy at the service mains to determine if it is safe for our technicians to open the equipment for data collection. The last thing we want to do is endanger our technicians and violate OSHA requirements.
ID Equipment and Collect Data
The Techs will affix an ID number then collect the equipment name and type, voltage and amp rating, manufacture, breaker type, size and trip settings, same for relays, fuse type and size, conductor sizes and lengths, and motor horsepower.
Enter Data into Engineering Software and Calculate Incident Energy
We enter this into our EasyPower engineering software and generate an incident energy analysis. We then review the analysis for equipment with an incident energy over 12 calories per centimeter squared and check upstream to see if it can be reduced by selective coordination.
Perform a Short Circuit Study
We perform a short circuit study which is used to evaluate the interrupting rating of the protective devices, such as circuit breakers, fuses, and switches and the equipment that it is installed in. Underrated equipment can fail, sometimes catastrophically, when subjected to short circuit currents that exceed their tested maximum values.
Perform a Coordination Study
A coordination study will be performed to determine proper protective device settings that will quickly isolate system faults and minimize equipment damage and downtime. How in depth you want us to coordinate is depending on the complexity of the facility. If your facility consists of mostly molded case breakers with nonadjustable settings and fuses, then we would only perform the coordination between the largest circuits in the facility i.e. larger motor and feeder circuits to distribution boards. An in-depth study of each circuit if preferred would add to the cost of the analysis.
Install Arc Flash Labels and Review
We then contact you with our recommendations to better coordinate the system and/or reduce the incident energy levels, if possible. If you accept our recommendations, we will change the settings and produce the report, if not we will build the report as is. Once we install the arc flash labels on the equipment, we will setup a time to review the report, drawings, and arc flash labels with you and discuss any deficiencies or possible ways to mitigate the incident energy levels.