Code Quiz

Oct 7, 2005 11:02 AM, By Steven Owen

Question. A small strip mall consists of the following 10 tenants: a pharmacy; a 24-hour emergency medical treatment center, which provides a limited amount of critical care; and eight different retail shops. The common service disconnecting means for the entire group of tenants is equipped with ground-fault protection (one service and 10 feeders). Does the Code require any additional level of ground-fault protection at any of the feeder disconnecting means?

A) No. An additional level of ground-fault protection is not required for this commercial occupancy.

B) No. There is no requirement for any GFCI protection at any service or feeder level for this commercial occupancy.

C) No. Similar to other health-care occupancies (generally hospital complexes), ground-fault protection is required for the feeder level (as well as the service disconnecting means). This applies only to the medical tenant as listed above.

D) Yes. Similar to other health-care occupancies (generally hospital complexes), ground-fault protection is required for the feeder level (as well as the service disconnecting means). This applies to all tenants in the example above.

Answer: D

Explanation: Section 517.17 of the 2005 NEC was revised to require a second level of selective ground-fault protection for all occupants of multiple occupancy buildings where one or more of the occupants has critical-care areas or uses electrical life-support equipment. This rule also applies to buildings that provide essential utilities or services for the operation of critical-care areas or electrical life-support equipment. The requirement is set up so that a ground-fault on any feeder in any occupancy should not trip the ground-fault protection equipment (GFPE) at the service, and therefore, initiate a power loss for all occupancies, including those that do not have critical-care life support equipment. This requirement has been in effect for some time now in health-care/hospital complexes. This change now extends the rule to retail and other similar complexes.