CBET - Certified Biomedical Equipment Technician Electronics and Electrical Safety Questions and Answers

Question 1

According to NFPA 99, what is the maximum allowable chassis leakage current for a new, cord-connected, non-patient care-related electrical appliance used within the patient care vicinity?

Accepted Answer

500 microamps

Answer

100 microamps

Answer

300 microamps

Answer

10 milliamps

Question 2

A biomedical equipment technician is performing an electrical safety inspection on a portable medical device. The resistance measurement between the ground pin of the attachment plug and the device's metal chassis should be less than what value to be considered safe?

Accepted Answer

0.5 ohms

Answer

0.1 ohms

Answer

1.0 ohm

Answer

5.0 ohms

Question 3

Which of the following describes the primary danger associated with microshock?

Accepted Answer

A very small current applied directly to or near the heart, potentially causing ventricular fibrillation.

Answer

High-voltage burns on the skin surface.

Answer

A large current passing through the limbs, causing muscle contraction.

Answer

A static discharge that causes discomfort but no lasting harm.

Question 4

A newly installed, permanently wired (fixed) piece of medical imaging equipment is being tested. Before any grounds are connected, what is the maximum allowable ground leakage current according to NFPA 99 standards?

Accepted Answer

10 milliamps

Answer

500 microamps

Answer

1 milliamp

Answer

5 milliamps

Question 5

What is the primary function of an isolation transformer in medical equipment used in a hospital operating room?

Accepted Answer

To create an ungrounded electrical system that reduces the risk of macroshock from a single fault.

Answer

To increase the voltage for high-power devices.

Answer

To convert AC power to DC power for sensitive electronics.

Answer

To provide a grounded power source for all connected equipment.

Question 6

When testing a medical device with patient-applied parts (like ECG leads), the international standard IEC 60601-1 establishes specific, very low leakage current limits. This is primarily to protect against which hazard?

Accepted Answer

Microshock

Answer

Macroshock

Answer

Radiofrequency interference

Answer

Overheating