By Ark Tsisserev M.Sc. P.Eng. FEC
By Ark Tsisserev M.Sc. P.Eng. FEC
May 26, 2017 – Which areas of a healthcare facility’s electrical system must be tested for voltage difference between ground points, for ground return path voltage rise in grounded systems, or for impedance to ground in isolated systems?
Which loads in a healthcare facility are considered essential system loads, and what kind of power supply must be provided to them?
These questions are often asked by the electrical designers and contractors, and the answers can be found within the following documents:
• National Building Code of Canada (NBC)
• CE Code-Part I
• CAN/CSA Z32-15 “Electrical safety and essential electrical systems in healthcare facilities”
NBC Article 22.214.171.124. states an emergency electrical power supply system for emergency equipment required by the building code (i.e. for essential electrical system loads, as described in Section 24 of the CE Code) must be installed in conformance with CAN/CSA Z32-15.
Z32-15 defines an emergency electrical power supply system as:
one or more in-house electrical generator sets intended to be available if all other supplies fail, and capable of supplying all of the essential loads.
Z32-15 defines an essential electrical system as:
an electrical system that has the capacity of restoring and sustaining a supply of electrical energy to special loads if the normal supply of energy is lost.
Section 6 of Z32-15 provides requirements for those essential electrical systems, and explains the essential electrical system consists of both the emergency equipment required by the NBC and special loads that are intended to provide effective and safe patient care in a healthcare facility.
Z32-15 Table 6 classifies essential system loads and branches, and their intended performance (vital, delayed vital or conditional) for a specific type of patient care.
Is this correct for all healthcare facilities?
So it seems some of the questions posed at the outset have been answered. But are there any differences in electrical installations between hospitals and, say, doctors’ offices?
CE Code Section 24 helps bring clarification. First, some history: prior to the 2002 edition of the CE Code, Section 24 was limited only to electrical installation requirements in patient care areas of hospitals. When the 19th CE Code was published in 2002, the Scope of Section 24 had been expanded to cover installations within patient care areas of, not hospitals, but healthcare facilities.
As such, the definition of “hospital” was deleted from Rule 24-002 “Special terminology” and a new definition for “healthcare facility” was added.
This change from hospital to healthcare facility was made throughout CE Code Section 24 and Appendix B to harmonize with CSA Z32, which separates healthcare facilities into three classes:
1. Healthcare facility, Class A
A hospital, so designated by Canada or one of its Provinces or Territories, where patients are accommodated on the basis of medical need and are provided with continuing medical care and supporting diagnostic and therapeutic services. (Example, a typical public hospital.)
2. Healthcare facility, Class B
A facility where residents, as a result of physical or mental disabilities, are unable to function independently and are accommodated due to a need for daily care by healthcare professionals. (Example, a nursing home.)
3. Healthcare facility, Class C
A facility where ambulatory patients are accommodated on the basis of medical need and are provided with supportive, diagnostic, and treatment services. (Example, a walk-in clinic.)
Z32-15 provides a variety of examples of such healthcare facilities in addition to hospitals, including surgical, outpatient and doctors’ clinics, dentist offices, and psychiatric and rehabilitation facilities.
Impact on your wiring practices
So facilities that were previously not included under Section 24 now have to follow the electrical installation requirements for Patient Care Areas (Rules 24-100 to 24-114), which have very specific criteria for circuits, bonding, receptacles and other equipment.
Which means the electrical installation in a typical doctor’s office located in an commercial building follows the same requirements as the patient care area of a large teaching hospital.
If you think these installation requirements seem rather drastic and excessive for the patient care areas of, say, a psychiatrist or massage therapist—whose offices are likely established in a typical commercial unit where there have never been any special requirements for receptacles, bonding, etc.—you’re right. They absolutely would be.
That’s why the relevant Rules of Section 24 apply to the installation of electrical wiring and equipment within patient care areas of those types of healthcare facilities where permanently or cord-connected electro-medical equipment is used for the purpose of intentional contact at a patient’s skin surface, or internally during the patient’s treatment, diagnosis or monitoring.
Your inspection authority may require the involvement of a professional electrical engineer at the permit and installation stages to ascertain the specific class of healthcare facility, the conditions of use of the electro-medical equipment, and to supervise tests referenced in the Appendix B Note for CE Code Rules 24-104(1) and 24-112.
Some jurisdictions provide additional clarifications to electrical contractors on the application of Section 24 requirements.
Again, where the installation of electrical wiring and equipment is done in patient areas of those types of healthcare facilities where permanently or cord-connected electro-medical equipment is used for the purpose of intentional contact at a patient’s skin surface or internally during the patient’s treatment, diagnosis or monitoring, then all applicable provisions of CE Code Section 24 must be met, and all test requirements for voltage drop, voltage difference between ground points, impedance to ground, etc., as mandated by Section 5 of CSA Z32-15 must be met.
And, as usual, authorities having jurisdiction must be consulted by designers and contractors contemplating electrical installations in the patient care areas of healthcare facilities.
Ark Tsisserev is the former chief electrical inspector for the City of Vancouver, and immediate past chair of the CE Code-Part I Technical Committee. He is both chair of CSA Group’s Strategic Steering Committee for the requirement of Electrical Safety, and the Canadian National Committee on IEC 60364 “Low-voltage electrical installations – Part 1: Fundamental principles, assessment of general characteristics, definitions”. Currently a senior associate with AES Engineering, Ark is a certified electrical inspector in British Columbia, and a registered Professional Engineer with a Masters in Electrical Engineering.