Code Change Summary: A new code section was added to address surge protective devices (SPD’s) for fire pump controllers.

A surge is a transient wave of voltage or current. The duration is not consistent but is usually less than a few milliseconds. Transients and Surges can have peak values in excess of 10kA or 10kV. During a surge, the waveform has a very rapid rise to the peak and then falls off at a much slower rate. Transients and Surges can be caused by external sources such as lightning or short circuits, or from internal sources such as variable speed drives, contactor or capacitor switching.

The study, “Data Assessment for Electrical Surge Protective Devices” commissioned by the Fire Protection Research Foundation, provides results of a 2014 survey of facility managers concerning surge damage.  It shows that 12% had damage to fire pumps due to voltage surges.  This damage could have been prevented with properly sized SPD’s. 

The new code section provides necessary requirements for fire pumps which are extremely critical for life-safety. As seen in the NFPA Research Foundation report there are a significant number of fire pump installations that suffer damage that could have been prevented by a SPD. The purpose of the NEC^® is the practical safeguarding of persons and property from hazards arising from the use of electricity. Surges are a hazard that occurs from the use of electricity and it makes sense to justify the code change based on the fact that a fire pump controller damaged by a surge may not perform as intended when it matters most.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC^® edition of NFPA 70.