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 Post subject: Qualifications to Perform Arc Flash Risk Assessments?
PostPosted: Mon Aug 19, 2019 11:24 am 

Joined: Mon Nov 10, 2014 11:01 am
Posts: 22
This is a difficult question which brings a mix of responses. My main thought is that the assessment project needs to be performed by a registered professional engineer (PE) – electrical. However, having this requirement will not assure you an assessment is being performed by a thorough and competent electrical engineer.
In performing an arc flash risk assessment, the lead person needs to have a strong commercial/industrial background where you have large electrical systems. In performing these studies there are many options and only experience will provide the correct approach. Normally, I would require a person with their PE license, but I have been working with one company where one of the owners is an electrical engineer but doesn’t have his PE. The other owner has been a licensed master electrician with many years of experience. The company and its leaders definitely know what they are doing. Thus, I would not want to eliminate them from doing a study for me.
I am an electrical engineer with 55 years of experience, licensed in several states. My electrical engineering experience consist of design and project management for electrical control systems and power systems, mostly heavy industrial. I’ve performed over 50 arc flash studies, large and small, working both in the field and building software models using SKM software. In addition, I’ve been hired as an expert witness, investigating electrical accidents involving fire, deaths and verified other contactor arc flash studies. I feel my years of experience offers the skill to perform an accurate arc flash risk assessment.
Examples of Poor Arc Flash Risk Assessments:
In looking for a company to perform an arc flash risk assessment, one might think going to one of the major electrical equipment manufactures and have them perform the study. I know some of these companies provide this service. I have reviewed two studies that were performed by large electrical equipment manufacturers. Both studies were severely lacking in quality.
One company’s study assumed that all cables were 10’, unless the customer provided actual cable lengths. The other study had the electric utility’s short circuit current modeled all wrong.
In one accident I investigated at an industrial plant, the plant manager had decided that they needed to have an arc flash risk assessment performed. So, they went to the local electrical distributer who they normally used. The distributor obtained a quotation from one of the major electrical equipment manufacturers. The plant manager rejected the quotation as being way too expensive, so the distributor went looking. They came back with another quotation. This time they brought in a quotation for $10,000. My rough estimate is that the study would have cost between $25,000 and $30,000. The distributor knew nothing about the company other than what was on their website. The supplier claimed many years of combined testing, repair, troubleshooting experience as well as in-depth knowledge of arc flash hazards. The distributor went ahead and recommended them without further checking.
The study was performed by only walking around the factory and making a list of all the electrical panels, disconnect switches, etc. and their amp ratings. They built a spreadsheet and assigned incident energy information based upon a bogus formula they developed. They labeled all 30 A panels with an incident energy of 0.454 Cal/cm2 (130 panels), all 60 A panels at 0.655 Cal/cm2 (26 panels) and so on. For the main switchboard for the plant, they calculated an incident energy of 27 Cal/cm2 whereas my calculations determine that it was 149.5 Cal/cm2.
This study, as well as other problems, resulted in the main electrical maintenance person working on the main switchboard without de-energizing it, even though there was no valid reason for doing so (pressure from management). While working on the switchboard an insulator failed resulting in a major arc flash event. One reason for going ahead with the energized work was the incident energy rating of only 27 Cal/cm2. In addition to improper calculations, the arc flash company provided inadequate training on the hazards; only training for 1.5 hours, if that long. As a result of the insulator failure, the maintenance person suffered 3rd degree burns over 40 to 50% of his body requiring massive skin grafting and medical bills in excess of $13,000,000. And there is much more to this horror story.
So, the question is, how do we qualify a supplier to perform arc flash risk assessments?
1. If the price is very low as compared to other suppliers, watch out. Going cheap my just result in an accident as described above.
2. An Ideal Condition: Obtain from the supplier the full arch flash risk assessment report for a project of similar size. This report must contain a detailed one-line diagram showing all le lengths the parameters used in the study, such as, cable lengths, etc. Probably most suppliers will be reluctant to provide anything but a sample report. Then, do you have the knowledge to interpret the report.
There needs to be a better approach for companies to evaluate their suppliers.


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 Post subject: Re: Qualifications to Perform Arc Flash Risk Assessments?
PostPosted: Wed Aug 21, 2019 8:02 am 
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Joined: Mon Jan 18, 2010 11:35 am
Posts: 524
Location: Wisconsin
I know of many companies, usually small ones, that only provide the AF incident energy results. They consider the software model (input data, actual output report, and assumptions/option choices) to be propriety material not to be shared with their customer.

This should be part of the vetting process. After all if you don't know what is going on in the model, how can you trust the results.


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 Post subject: Re: Qualifications to Perform Arc Flash Risk Assessments?
PostPosted: Thu Aug 22, 2019 6:33 pm 

Joined: Mon Oct 10, 2016 5:31 am
Posts: 4
I have pondered this question for a long time. I fall into the class of master electrician that I believe could do a very good study and I would be confident in my results. With that said, I don't have the time to dedicate to a study. I have seen in our plant several questionable results by major equipment manufacturers and other engineers. For our latest project I got involved with specifications for the study ( with the help of this board ) and am very pleased with our progress. I may not like some methods used but I am given the reasoning and accept it. Alway thing to learn.
I think the answer may be to qualify the company instead of the individual. I would like to see an inspection of sorts or pull a permit to preform a study. I think there are too many small building owners that have no way of knowing if their study was done well and should have some recourse.
Well thats my 2 cents, I will be interested to hear other opinions.

Jeff


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 Post subject: Re: Qualifications to Perform Arc Flash Risk Assessments?
PostPosted: Mon Aug 26, 2019 6:06 am 

Joined: Tue Dec 31, 2013 12:19 pm
Posts: 32
Thanks jcp for reminding everybody that arc flash studies are serious business.

After reviewing multiple studies from "national" firms, most notably from big name electrical equipment manufacturers, I concur the quality and standard of care are not there. Too many short-cuts, too many assumptions that simply aren't true but do affect the results, not looking at equipment that they didn't supply, not coordinating the actual available short-circuit with the local utility, the list of short-comings is lengthy. Another big complaint, not giving you the input data so that their results are reproducible.

As far as should arc flash studies be done by an engineer or somebody else who has the training. I agree with the contention that experience and some good quality training like Jim Phillips classes, you don't have to be an engineer to learn how to do these studies. However, the standard for calculating arc flash is IEEE 1584. IEEE is Institute of Electrical and Electronics Engineers, not electricians, nor electrical equipment distributors. These are engineering calculations taken from an engineering standard. With the 2018 edition of IEEE 1584, whether arc flash studies should be performed under the supervision of an engineer is no longer a question. According to law in nearly every state, they absolutely should be. In nearly every US state, the requirement for engineering practice is limited to areas of practice for which they have specific training.

The accident you sited is horrible and needn't have resulted in such serious injuries, rhetorically, where was the standard of care, and where is the liability? I've always railed against the commodity mentality for engineering services. Cheapest isn't always best and neither is most expensive. Qualifications, training, and experience do matter.


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