Electrical Safety Testing for Biomedical Devices: Why it Matters

Introduction 

Electrical safety testing for biomedical devices has been in practice for almost a century. As technology has evolved, safety standards have adapted to ensure that electrical safety testing remains relevant and effective. However, not all consumers and manufacturers fully comprehend the importance of proper electrical safety testing.

Importance of Electrical Safety Testing Electrical safety testing is crucial to prevent shock hazards that can range from a tingling sensation to a lethal jolt. Shock hazards can exist when voltage and current are accessible to the operator or patient with respect to earth ground. Identifying, correcting, and eliminating shock hazards are the primary reasons for electrical safety testing.

Leakage Current Testing Leakage current is one of the most critical parameters of potential danger to patients or caregivers. It does not take much electric current flowing through the human body to cause harm, especially for patients with weakened immune systems. Therefore, measuring leakage current in electrical medical products is crucial.

Leakage current is measured to ensure that direct contact with the medical equipment is highly unlikely to result in electrical shock. The tests simulate a human body coming in contact with different parts of the equipment, and the measured leakage current values are compared with acceptable limits based on the type of product being tested.

Why Do We Need Electrical Safety Testing for Biomedical Devices? As noted in OSHA’s (The Occupational Safety and Health Administration) Publication 3075, a shock hazard is considered to exist at an accessible part in a circuit between the part and ground or other accessible parts if the potential is more than 42.4 V peak and the current through a 1,500KΩ load is more than 5 mA. Studies have concluded that the human body can feel the sensation of an electrical shock with as little as 1.0 mA of current.

According to NFPA 99 (The National Fire Protection Association), just three conditions occurring simultaneously can result in a shock to a patient or caregiver: one part of the body is in contact with a conductive surface, a different part of the same body is in contact with a second conductive surface, and a voltage source drives current through the body between those two points of contact.

Standards and Regulations There are several codes and standards that govern electrical safety testing for biomedical devices. These include:

• FDA: U.S Food and Drug Administration
• IEC: International Electrotechnical Committee
• NFPA: National Fire Protection Association
• ANSI: American National Standards Institute
• AAMI: Advancement of Medical Instrumentation
• BSI: British Standards Institute
• ISO: International Organization for Standardization
• ECRI: Emergency Care Research Institute
• HEMA: Health Industry Manufacturers Association
• NEMA: National Electrical Manufacturers Association
• NEC: National Electrical Code

Conclusion

Electrical safety testing is crucial for biomedical devices to prevent potential shock hazards to patients and caregivers. Leakage current testing is one of the most critical parameters for biomedical devices. Compliance with codes and standards is essential to ensure that devices are safe and reliable for their intended purpose.