National Electrical Code

No Room for Error

Dec. 14, 2015

Interpreting the intent of the National Electrical Code

All references are based on the 2014 edition of the NEC.

Section 517.19(C)(1) was added to the 2014 edition of the NEC in order to correlate with Sec. 6.3.2.2.6.2 of The Health Care Facilities Code (NFPA 99). Both codes now require operating rooms to have a minimum of 36 receptacles. This is a smart idea due to the amount of equipment that is likely to be used during an operation. But when it comes to figuring out the requirements for the branch circuits supplying power to these receptacles, it’s not so clear as to how many receptacles, if any at all, need to be connected to the critical branch of power.

Ecmweb Com Sites Ecmweb com Files Uploads 2015 12 Nec Operating Rooms

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Section 517.19(C)(1) of the NEC states that at least 12 of these 36 receptacles must be connected to either a normal power branch circuit or a critical power branch circuit. What about the other 24? Could they also be connected to a normal power branch circuit? The NEC simply doesn’t say what circuits to connect the other 24 receptacles to. That could potentially lead to all of these remaining receptacles being connected to normal power circuits — with none being connected to the critical branch power.

I’m not so sure that is the intent of either code in this particular case. However, the literal wording could allow this to happen. This would be especially bad for the patient on the operating table if the power were to go off during the middle of an operation. I don’t think the lawyers representing the health care facility would prefer this situation either. Perhaps a deeper look into the Health Care Facilities Code could help clarify things a bit.

Section 4.1.1 of NFPA 99 states, “Activities, systems, or equipment whose failure is likely to cause major injury or death of patients, staff, or visitors shall be designed to meet Category 1 requirements as detailed in this code.” Section 6.3.2.2.1.2 of that same code then requires Category 1 spaces to be served by circuits from a critical branch panelboard plus a minimum of one normal power circuit or another critical branch circuit originating from a different transfer switch. While this does not specifically address which circuits to connect the receptacles to, I believe the intent is to allow some of the operating room receptacles to continue to provide power in the event of a loss of power from the normal power source. Of course, it’s always best to check with your AHJ whenever you have any questions regarding interpretation of a code requirement.

About the Author

Russ LeBlanc | Owner

Russ started in the electrical trade as an apprentice in 1985. He worked his way up to become a Journeyman Electrician and then eventually became a Master Electrician and Licensed Construction Supervisor. In 1999 Russ become an Electrical Instructor for The Peterson School of Engineering in Massachusetts where he developed his passion for teaching, and quickly became Department Head of Electrical Instruction. Russ has taught thousands of apprentices, electricians, engineers, inspectors, and other electrical professionals during his career as an instructor. He continues to provide electrical professionals with Electrical Code seminars, Arc-Flash Awareness training seminars and educational material through his LeBlanc Consulting Services in North Reading, MA whose specialty is educating electricians. He has been an active member of the NFPA Electrical Section and has authored hundreds of National Electrical Code proposals and comments which have become Code rules to improve the safety for the electrical industry. Russ is also an IAEI certified Electrical Inspector.

Please visit www.russleblanc.net for more information.