Safety Knights

An arc flash study helps the worker know what the voltage is inside the panel. So when he goes to work inside it (a qualified electrician), he knows what the voltage is, hazards and PPE to use. There is also a lot more information on these labels on the arc flash and electrical boundaries for certain types of qualified workers. I would recommend that you take a low voltage training class (e-hazard has an awesome 1 day class) so you understand the importance of these labels to help the qualified electricians.

NFPA 70E, Section 130.5 Arc Flash Analysis – requires an arc flash risk assessment shall be performed to determine the risk, safety related work practices required, the arc flash boundary, the incident energy at the working distance, and the PPE that people within the arc flash boundary shall use.

I am not sure what qualifications a company needs to do the study but I know it is a lot of work and must be done by training and qualified people. I would confirm the company has done it in the past or is one of the main tasks they do.

1)An arc flash study is the measurement of how much energy can come from an electrical component should something go wrong. This value is not the voltage that comes from the panel (ie 120V/240V) but rather the energy, measured in calories/cm2. Once you know the Calories/cm2 number you will know what type of arc flash suit the electrician should wear when performing the work. Example: After an arc flash study is performed an electrical panel has a label saying that the incident energy is 25 calories/cm2. The electrician will put on their suit rated for 25 calories/cm2. If the panel has a label that states the incident energy is 40 calories/cm2, the electrician will put on their suit rated for 40 calories/cm2.
2) A qualified company should perform this work. Typically electrical engineers will come on site- They will talk with the power company to see how much power is coming from the utility company, they will assess the main circuit breaker, transformers, power distribution, wire length, wire gauge, wire type, motor control center, they will take voltage readings. Your electrician will need to help them navigate the facility and show them the different panels. One of the deliverables will be an single line diagram. Arc flash studies typically are in the 100,000s of thousands of dollars and should be done by qualified people only.

Remember, PPE is the last line of defense. You should do everything in you power to de energize the electrical circuit before putting people in front of live electrical equipment.

Just my 2 cents, arc flash hazard is something that needs to be in your site’s safety program. An arc flash will vaporize metal. Yes, turn metal into vapor. The temperatures involved and resulting pressure wave are very serious.

Slow motion example:
https://m.youtube.com/watch?v=PO6see7_ODY