700.27 Coordination Study on renovation projects?

[MEP_PM]

I have a general knowledge of the purpose of coordination studies but I?m not really clear on how to approach this on a renovation project. For example: A healthcare facility is about to start a renovation where most of the main electrical equipment will remain. However there are several new breakers being added to existing MDPs, new transformers, and new branch panels that connect to existing subpanels. There is not an existing coordination study to reference.

Who should be responsible for providing the coordination information on the existing equipment? Should the engineer investigate the existing conditions and provide information on the drawings where the new work starts? Are there assumptions that are typically made? Or should the Electrical Contractor/Equipment Supplier be required to complete a coordination study on the existing system as it affects their new work?

Don?t worry, I won?t be performing any work or calculations. I?m just trying to understand the best way to approach this.

 

[ron]

Some EE's require the vendor/manufacturer to provide the overall study via the bid specification.
Some other EE's perform the study them self and start with the settings of the first existing device in the distribution that will serve the new equipment. If the new stuff coordinates with the existing device, then some will guess that the existing device already coordinates with devices further upstream.
And some others probably know that the existing settings don't coordinate and perform the study them self with existing and new, to show the AHJ that all works together.
Some how you need to show the AHJ proper coordination.

How it happens is based upon the EE's contract with the Owner.

 

[jim dungar]

In Wisconsin, the simplistic answer is: all of the new equipment must meet the current code requirements for selectivity. The existing equipment does not need to be considered.