There is a recent trend in the review process for electrical distribution equipment submittals. These days, I see more of an effort toward a collaborative submittal review, where the manufacturer’s information is reviewed concurrently with the design and construction team. The contractor, construction manager (CM), manufacturer, owner, and design engineer all sit in a room and walk through a submittal — sometimes in painstaking detail. Although this sounds laborious, it is actually extremely effective in resolving concerns or questions regarding the proposed equipment.
In a typical review process, the effort consists of many weeks of manufacturer submittal compilation, contractor input, CM remarks, engineering review, and owner comments, which then result in manufacturer modifications to the submittal. Once the submittal is modified, the whole process starts again — and usually occurs several times. By bringing all the parties together for a concurrent review, all of the issues are laid out on the table and addressed immediately. Not only is this a forum where questions are raised, but answers are also provided, which often leads to more questions. Breaker configurations and ratings, switchboard attributes, and compliance with the specifications and contract documents are discussed and validated. By having a roundtable submittal discussion, the process is accelerated and enhanced by multidisciplinary experts bringing their input to the effort.
Another shift in the review of the electrical distribution equipment is the requirement to provide a submittal for a selective coordination, arc flash, and fault current study prior to reviewing and approving the electrical distribution equipment. Back in the old days, these studies were not requested to be submitted before the equipment was ordered — or sometimes even at all. This often resulted in a significant amount of time and money spent trying to modify the new equipment so it could be coordinated and have a withstand and fault condition rating specific to that particular installation. There also were situations where equipment was ordered with a higher fault current rating and with more bells and whistles than was necessary for the installation. This conservative design was often done to ensure a compliant system regardless of the design variables. This practice typically added money to the project for characteristics that were not necessary.
Let’s not be too quick to judge and point a finger at the engineer, the contractor, or equipment supplier for this scenario. In the old days, we did not always know which manufacturer we would be using, the equipment was not as intelligent as it is today, and selective coordination was not a code requirement, so the options of equipment available to submit, review, and approve was a completely different process. We did our due diligence by assuming an infinite bus for the utility and checked select loads utilizing manufacturers’ onion skin curves for coordination. We would do a spot check based on curves to coordinate the system, but because each manufacturer’s devices have different characteristics, the coordinated device selection may not necessarily be valid. Even with this coordination, the fault current still needed to be confirmed. The required fault current could change the frame size of the breaker in order to get the necessary AIC rating, which then affects the coordination curves, which then may change other pieces of equipment. Different breakers require different space configurations, and the larger the frame size the larger the panel. When a panel has to increase in physical size, the electrical room is affected, which then impacts the architecture and … see how this just snowballs out of control?
These days, we have more control over the variables and more tools as design engineers to specify a system based on known parameters. We do preliminary calculations, so when the information is provided to the contractors and manufacturers their role is to confirm the basis of design with their equipment instead of starting from point zero. As you see, there is a lot of upfront preparation required for the design documents and before the submittal documents are even submitted for a job. Why make it more difficult for the next stage of the process by playing pass the submittal? By providing the construction team with all of the required parameters upfront, using the actual site information and gathering all of the parties together for a concurrent review, the process is streamlined and the best and most cost-efficient solution can be implemented efficiently.