NEC 517 for Apprentices: Patient Care Spaces, Redundant Grounding, Receptacles at the Bed and the Essential Electrical System

Tsai Electro is an independent learning site. Not affiliated with TDLR, PSI or NFPA. We explain the ideas in our own words and do not reproduce NEC text. Check every rule and table value in your own 2026 NEC, follow the project documents and NFPA 99 requirements the facility uses, and follow your supervisor and the local inspector.

Patient care space categories

The facility’s governing body decides the category of each patient care space, and the electrical rules follow from that.

Category	Typical spaces	Why it matters
Category 1 (critical care)	Operating rooms, intensive care, emergency treatment	Failure could cause major injury or death
Category 2 (general care)	Patient bedrooms, exam rooms	Failure could cause minor injury
Category 3 (basic care)	Spaces where failure is not likely to cause injury but can cause patient discomfort	Requirements depend on the space
Category 4 (support)	Spaces where failure is not likely to have a physical impact on patient care, often waiting rooms, offices and storage	Not a patient care space for these rules

On the job, the drawings and the facility tell you the category of each room. You do not choose it.

Redundant grounding

Branch circuits that serve patient care spaces need two separate grounding paths (NEC 517.13):

• The wiring method itself. The branch circuit is installed in a metal raceway, or in a cable whose metallic armor or sheath qualifies as an equipment grounding conductor under 250.118, and the boxes and fittings in that path are metal. Ordinary Type MC with an armor that does not qualify on its own is not enough. Many jobs use Type MC cable listed for health care facilities, often called HCF cable.
• An insulated copper equipment grounding conductor. It runs with the branch circuit conductors and connects to the grounding terminals of receptacles and the metal enclosures and equipment in the patient care vicinity.

If one path is damaged, the other is still there. That is the reason for the rule: in patient care, a lost ground can expose a patient to current through equipment connected to their body.

Receptacles and circuits at the bed

Bed location	Minimum receptacles	Branch circuits
General care (Category 2)	8 (NEC 517.18)	Normally at least one from the critical branch and at least one from the normal system
Critical care (Category 1)	14 (NEC 517.19)	Normally at least one from the critical branch and at least one from the normal system; a critical branch circuit at a critical care bed serves only that bed location
Operating room	36	Set by its own rule in 517.19

The code allows some exceptions to the normal plus critical branch arrangement, for example where the beds are fed from two separate critical branch transfer switches. Check 517.18 and 517.19 before you plan the circuits.

• Hospital grade. Receptacles at general care and critical care bed locations are generally listed hospital grade. They are made to hold a plug firmly and survive heavy use.
• Pediatric areas. Receptacles in pediatric spaces are listed tamper-resistant or use a listed tamper-resistant cover (NEC 517.18).
• Identification. Receptacles and cover plates on the essential electrical system are identified, often with a distinctive color, and many facilities also label the panel and circuit number on each plate.

The essential electrical system

A hospital’s essential electrical system has three branches. Each branch is supplied through transfer switches, and in smaller systems the code allows one transfer switch to serve more than one branch:

• Life safety branch. Egress lighting, exit signs, fire alarm, alarms for medical gas systems and similar loads.
• Critical branch. Task lighting and selected receptacles in patient care spaces, including the critical branch receptacles at each bed.
• Equipment branch. Large equipment needed for patient care and building operation, such as selected heating, ventilating and medical vacuum equipment.

The wiring of the life safety and critical branches is kept independent of all other wiring, except in the places the code allows, such as transfer switches and certain shared enclosures. Check the branch rules in Part III of Article 517.

Worked example: counting receptacles on a nursing unit

A new nursing unit has 6 general care bed locations and 4 critical care bed locations, none of them operating rooms. Find the minimum number of receptacles at the beds.

1. General care. 6 beds × 8 receptacles = 48 receptacles.
2. Critical care. 4 beds × 14 receptacles = 56 receptacles.
3. Total. 48 + 56 = 104 receptacles at the bed locations, as a minimum.
4. Circuits. Assume the usual normal system plus critical branch arrangement. Then all 10 bed locations need circuits from both systems, and each critical care bed gets its own critical branch circuit, so plan both systems to reach every bed.
5. Check. 48 ÷ 6 = 8 and 56 ÷ 4 = 14, which match the minimums. The design can always add more.

Check yourself

1. What are the two grounding paths for a branch circuit in a patient care space? A metal raceway or qualifying cable armor, plus an insulated copper equipment grounding conductor.
2. How many receptacles does a critical care bed location need at minimum? 14.
3. Name the three branches of a hospital’s essential electrical system. Life safety, critical and equipment.

FAQ

Sources checked October 2026

• PSI Candidate Information Bulletin, Texas electrician examinations (updated September 15, 2026): https://test-takers.psiexams.com/api/content/bulletin/1682
• NFPA 70, National Electrical Code, 2026 Edition, Articles 250 and 517