Code Change Summary: Requirements for isolated ground receptacles in a health care facility have changed.

An isolated ground receptacle has a grounding terminal that has no contact with the receptacle mounting strap or yoke. When installed against a grounded metal box, the receptacle mounting strap is grounded. The receptacle’s isolated ground terminal is then connected to an additional insulated grounding conductor that is installed as a separate grounding path for the reduction of electrical noise on the sensitive electronic equipment plugged into the receptacle. See 250.146(D).

Receptacles installed in the patient care vicinity of a health care facility are often used for life saving medical equipment that is connected to the patient. Equipment grounding becomes increasingly important as more electrical equipment is connected to the patient which is why sections 517.13(A) and (B) work together to require redundant grounding for branch circuits serving patient care spaces.

First, 517.13(A) requires the branch circuit serving the patient care space to be installed in a metal raceway or metal cable that qualifies as an equipment ground, then 517(B) requires an additional insulated wire type equipment grounding conductor to be installed in the metal raceway or cable. Between the two, at least one grounding path will always be present to provide a safe condition for the patient.

A patient care vicinity (defined in 517.2) is located within a patient care space such as a hospital room. For the patient care vicinity, isolated ground receptacles are not permitted since the redundant ground path required by 517.13(A) and (B) cannot be assured by the isolated ground receptacle. Isolated ground receptacles are however permitted within the patient care space but only when installed outside the immediate patient care vicinity.

In the 2017 NEC^®, new rules remove the confusion about the number of equipment grounding paths required for branch circuits serving patient care spaces when isolated ground receptacles are used within the patient care space but outside the patient care vicinity. For such isolated ground receptacles, the new rules require the following:

• Since the branch circuit is still in the patient care space, the wiring method must be a metal raceway or metal cable that qualifies as an equipment grounding conductor per 517.13(A).
• Metal boxes, enclosures and non–current-carrying conductive surfaces of fixed electrical equipment must be grounded with a green insulated equipment grounding conductor installed with the branch circuit conductors to comply with 517.13(B).

The grounding terminal on the isolated ground receptacle must be connected by an insulated equipment grounding conductor with one or more yellow stripes which is permitted to pass through one or more panelboards without a connection to the panelboard grounding terminal bar as permitted in 408.40, Exception, so as to terminate within the same building or structure directly at an equipment grounding conductor terminal of the applicable derived system or service.

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.