AC Surge Protection and Power Quality Controls

From our discussions, it was indicated that the main AC power supply and sub-panels that feed areas containing sensitive electrical equipment are not provided with a surge protection device (SPD).  Because of the value and critical nature of the equipment housed at this facility, we recommended your organization consider providing such protection at the main panel and key sub-panels, and standardize the type of plug-in SPD units used at high-value/critical equipment.  A number of the areas we noted had “multi-outlet power taps” rather than an SPD.  As a general rule, plug-in SPDs should have a proper functioning indicator, built in short circuit protection, a correct wiring indicator (for the outlet into which it is plugged) and a UL1449 listing (3rd ed.).  SPDs for the electrical distribution system should be listed by an approved testing agency such as UL, and should be designed/selected for the loads that they will handle and installed by a qualified contractor.  Related to this, we noted that you may want to pursue a unit that also provides you with power quality monitoring to help in identifying and correcting power problems outside of surges that can also lead to equipment damage and failures.  At present, the 911 area uses the UPS devices as a means of surge protection; however, due to the cost of these units you may find that a well-designed SPD system will provide you with a higher level of protection at a lower cost and protect the UPS units from damage that could shut down 911 operations.