Healthcare and Electrical Safety Flashcards

Which class of electrical equipment relies solely on basic insulation for protection and has no grounding conductor?

Answer: Class 0

Class 0 equipment relies only on basic insulation with no additional safety measure such as grounding or protective extra-low voltage.

The maximum allowable chassis leakage current for a patient-connected device in a general care area per NFPA 99 is:

Answer: 100 µA

NFPA 99 allows a maximum chassis leakage current of 100 µA for patient-connected devices in general care (Category 2) areas.

In a patient care environment, 'equipotential grounding' primarily protects against:

Answer: Microshock from potential differences between grounded surfaces

Equipotential grounding ensures all conductive surfaces in a patient care area are at the same potential, preventing microshock from small current flow through the patient.

A biomedical technician discovers that the ground pin of a 3-prong medical device plug is broken. The safest immediate action is to:

Answer: Tag out the device and remove it from service

A broken ground pin eliminates the primary fault-current path, creating a shock hazard; the device must be removed from service immediately.

Which test instrument is used to measure the insulation resistance of medical electrical equipment to detect degraded insulation?

Answer: Megohmmeter (megger)

A megohmmeter applies a high DC test voltage (typically 500 V) and measures the resulting resistance to assess insulation integrity.

When performing an electrical safety inspection, a 'point of care' device is found to have a leakage current of 450 µA chassis-to-ground. This finding indicates:

Answer: A safety hazard requiring removal from service

450 µA exceeds both general care (100 µA) and critical care (10 µA) NFPA 99 chassis leakage limits, making the device unsafe for use.

The purpose of an isolation transformer in a line isolation monitor (LIM) system is to:

Answer: Isolate the power circuit from earth ground to reduce shock hazard

An isolation transformer breaks the direct connection to earth ground, so a single fault does not complete a shock circuit through a grounded patient.