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Wet locations and isolated systems in health care facilities

Posted By Ark Tsisserev, Tuesday, March 01, 2011
Updated: Wednesday, January 09, 2013

Let’s say, you are undertaking design and installation or inspection of such electrical installation in patient care areas of a health care facility. Do you consider certain parts of patient care areas as wet locations, and which criteria do you use for such consideration?

In light of these questions — which wiring methods should be used, and which types of equipment construction should be specified in design? Is use of a solidly grounded system allowed in patient care areas or must only isolated systems be used?

Let’s check which electrical safety requirements are applicable for design and installation of electrical equipment in respect to these subjects, where consistency of design, installation and inspection is far from perfect.

First of all, let’s state the following undisputed facts:

1. Installation requirements in patient care areas of health care facilities are governed by Section 24 of the Canadian Electrical Code.

2. Application of electrical safety associated with provision of health care and application of essential electrical systems in a health care facility are covered by the CSA standard Z32 "Electrical Safety and Essential Electrical Systems in Health Care Facilities.”

Section 24 of the CE Code and the CSA standard Z32 mandate a variety of very specific conditions related to electrical installations and to application of electrical safety in health care facilities. However, the object of this discussion is to concentrate on two particular issues indicated at the outset of this article.

First of all, let’s discuss the subject of wet locations in patient care areas.

This question might surprise some readers. Why would we discuss wet locations when we deal with electrical installations in patient care areas of a typical health care facility (i.e., in patient care area of a major hospital)?

The readers may be referred to Rule 24-106(2) of the CE Code which states: "24-106(2) Receptacles located in areas that are routinely cleaned using liquids that normally splash against the walls shall be installed not less than 300 mm above the floor.”

The question is: "Does Rule 24-106(2) refer to areas that are defined as wet location in Section 0?”

Before offering the answer to this question, let’s check the definition of wet location in Section 0.

Section 0 offers the following definition ofwet location, "Wet location – a location in which liquids may drip, splash, or flow on or against electrical equipment.”

After reading this definition, the Code users may immediately review provisions of Section 22, where use of electrical equipment and wiring methods in the environment with liquids that may drip, splash or flow on or against electrical equipment is governed by specific provisions. Rule 22-102(4) mandates that "where the electrical equipment is, or likely to be, exposed to splashing of water, it shall be of a weatherproof or watertight type of construction.” Furthermore, Rule 22-200(1)(a) mandates that conductors that are exposed to moisture must be of the types specified in Table 19 for exposed wiring in wet locations.

Section 24, however, does not make any references to wet locations for the wiring methods or for selection of electrical equipment. Z32 also does not provide any references to wet location for the purpose of application of electrical systems in health care facilities.


Appendix B Note on Rule 24-116 states: "Areas subject to standing fluids on the floor or drenching of the work area can create a condition where a patient or staff member can become a path for ground-fault current under fault conditions. Routine housekeeping procedures and incidental spillage of liquids are not intended to be considered for the purpose of this Rule.”

Therefore, the answer to our highlighted question above is the definite: "NO.”

This answer is based on the following criteria:

1. If the areas described in Rule 24-106(2) should be classified as "wet locations,” such areas would have to be referenced in Appendix B on Rule 22-002 for Category 1 locations.

2. If these parts of a patient care area (where a routine cleaning takes place by using liquids that normally splash against the floor and wall surfaces) are intended to be classified as wet locations, Section 24 would impose requirements for wiring methods and installation of electrical equipment — to conform to Category 1 of Section 22.

It should be noted, for example, that the EMT is not allowed to be installed in wet locations by Rule 12-1402(1), and the EMT is a commonly used raceway in patient care areas.

3. Rule 24-106(2) deliberately mandates a minimum height restriction for receptacles in parts of patient care area that are routinely cleaned by use of liquids, as such areas are not considered to be "wet locations.” Otherwise, such restrictions would not exist, and the receptacles installed in these areas simply would have to comply with Rule 22-108.

4. This rule only mandates a clearance from a receptacle location and does not stipulate otherwise that the area of cleaning with liquids is a wet location.

5. Z32 does not mandate any specific conditions in this regard in Clause 4.2.6, Patient Care Area Classification, although this standard covers all relevant aspects of electrical safety in health care facilities. It should be also noted that Z32 requires use of medical electrical equipment that is designed, constructed, tested and certified to very stringent provisions of the CAN/CSA–C22.2 No. 60601 series standards, and that these standards take into account required mitigation of any leakage and risk currents associated with a specialized use of this type of equipment.

Proponents of classifying these areas as "wet locations” argue that a typical operating room is a prime example of a wet location, as an OR is subject to standing fluids or drenching of the work area. However, the CE Code addresses this matter in Rule 24-116, by mandating GFCI protection of receptacles installed in such areas or by mandating use of isolated systems conforming to Rule 24-200. Impact of routine standing fluids or drenching of the work area is different (from the CE Code and Z32 perspective) from the impact of incidental spillage of cleaning liquids in patient care areas. The latter impact is not intended to be addressed by provisions of Rule 24-116. In fact, Appendix B Note on Rule 24-116 states: "Areas subject to standing fluids on the floor or drenching of the work area can create a condition where a patient or staff member can become a path for ground-fault current under fault conditions. Routine housekeeping procedures and incidental spillage of liquids are not intended to be considered for the purpose of this Rule.”

It should be noted that some CSA C22.2 No. 60601 series standards might also mandatea GFCI protection in the design and construction of specific cord-connected medical electrical equipment, but such requirements are outside the scope of the installation Code.

So, by now we should be comfortable with the conclusion that the electrical equipment and wiring methods in patient care area do not have to be selected for use in a "wet location,” and that only the receptacles in areas subjected to standing fluids on the floor or drenching of the work area must be protected by a GFCI of the Class A type or must be suppliedby an isolated system. Now is the appropriate time to discuss the Code and Z32 provisions for isolated systems.

Isolated systems are not specifically mandated by the CE Code to supply all loads in patient care areas.

In general, isolated power in operating rooms represents an outdated design and installation approach. The concept of using isolated systems was traditionally utilized in the past in order to reduce the risk of a spark which could cause an explosion in the presence of flammable anesthetic agents. Flammable anesthetic agents have not been used for quite some time. As such, isolated systems are required as the power supply sourceonly as an alternativeto solidly grounded systems under provisions of Rule 24-110 of the CE Code. Rule 24-110 states: "The branch circuits supplying receptacles or other permanently connected equipment in intermediate or critical care areas shall be suppliedfrom either a grounded system meeting requirements of Rule 24-102, or an isolated system meeting the requirements of Rule 24-200….”

Appendix B Note on Rule 24-116 explains in part that use of a GFCI of the Class A type for receptacles in areas subject to standing fluids on the floor is intended for those "locations within a patient care area where interruption of power to the receptacles by actuation of a GFCI is deemed to be acceptable in accordance with the provisions of CAN/CSA-Z32.

These receptacles are intended to be supplied by an isolated system where such power interruption to the receptacles is not acceptable in accordance with CAN/CSA-Z32.

It is interesting to note that 2009 edition of CAN/CSA-Z32 "Electrical Safety in Health Care Facilities” offers the following statements:

"5.11.1 General
Use of isolated power is not required by the Canadian Electrical Code, Part I, or by this Standard.
Note: The requirements of Section 24 of the Canadian Electrical Code, Part I, apply to the design and installation of isolated power systems.

H.2.13
The probability of persons receiving an unintended electric shock from a properly grounded system is very remote.

H.2.14
Because a grounded system does not require a line isolation monitor, isolating transformer, or special panelboard, additional space is not needed.

H.2.15
The capital cost is typically lower for grounded systems; however, additional testing is required on commissioning to ensure the safety of the system.

H.4 Choice of system
For intermediate and critical care areas, the decision to use a grounded system or an isolated system is made jointly by the provincial/territorial or federal body having jurisdiction, the HCF administration, and the professional engineer responsible for the electrical design.”

Many electrical designers and biomedical engineers responsible for operation of medical electrical equipment in patient areas of the health care facilities are of the opinion that an isolated system provides a very intangible additional level of safety to the patients and staff. Z32 mandates a very stringent testing protocolfor the electrical equipment and branch circuitssupplied by a solidly grounded system. Experience has demonstrated that the power supply provided by an isolated system may, in fact, camouflage electrical safety problems with medical electrical equipment. Thus, from a practical view point, use of an isolated system is not a desirable alternative to a solidly grounded system.

So, where the areas that are subjected to standing fluids on the floor or drenching of the work area can create a situation where a patient or staff member may become a path for ground-fault current under fault conditions, where means to mitigate such situation by the appropriate maintenance procedures are not deemed to be practicable and where a GFCI protection of receptacles in such areas is not acceptable due to a possible power interruption, a decision to use an isolated system as an alternative to a solidly grounded system is a combined decision by the HCF administration, respective regulators and design professionals.


Read more by Ark Tsisserev

Tags:  Canadian Perspective  March-April 2011 

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