CABT Healthcare and Electrical Safety 3

Question 1

Which NFPA 99 category designation applies to spaces where failure of equipment is likely to cause major injury or death to patients or caregivers?

Accepted Answer

Category 1

Answer

NFPA 99 Category 1 (formerly 'critical care') covers areas where equipment failure could result in major injury or death.

Question 2

Which physiological effect occurs when 60 Hz AC current in the range of 10–20 mA passes through the thorax?

Accepted Answer

'Let-go' threshold exceeded, causing inability to release the conductor

Answer

At 10–20 mA, sustained muscle tetany prevents voluntary release of the energized conductor, defining the 'let-go' threshold.

Question 3

A line isolation monitor (LIM) alarms at 5 mA. Which action is most appropriate?

Accepted Answer

Unplug equipment one at a time to identify the faulted device

Answer

Sequentially unplugging devices while watching the LIM reading identifies the faulted equipment without interrupting essential power.

Question 4

What does the term 'double insulation' (Class II equipment) mean?

Accepted Answer

Two independent layers of insulation so no grounding conductor is needed

Answer

Class II (double-insulated) devices have two independent insulation barriers, eliminating the need for a protective earth connection.

Question 5

For cardiac catheterization laboratory equipment, NFPA 99 specifies a maximum patient lead leakage current of:

Accepted Answer

10 µA

Answer

In critical care (Category 1) areas with intracardiac leads, the patient lead leakage limit is 10 µA to prevent microshock-induced fibrillation.

(CABT) Certified Associate in Biomedical Technology Practice Test