What is leakage current? The importance of leakage current to medical power supply

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• Introduction: What is leakage current?
• Why is controlling leakage current important?
• Why medical power supplies need low leakage current?
• What is the safety regulation on the leakage current of medical power supplies?
• Why choose FSP for low leakage medical power supplies?
• Summary

Author: FSP Group

Introduction: What is leakage current?

Leakage current is a term used to describe current that is non-functional. Current that flows from either a DC or AC circuit to the ground, a chassis or any other conductive component in the absence of a grounding system is considered leakage current. Leakage current from the input or output cannot be avoided, but it must be controlled. There are specific limits for leakage current, depending on the industry or application.

Leakage current in different types of equipment flows when there is an electrical connection between the ground and a conductor, which has not been designed intentionally. If the equipment you are using is not grounded correctly, current will flow through other energized components or conductors. In the case of electrical devices, leakage current usually occurs as a result of faults in insulation or the fabrication of materials used to make parts, such as semiconductors.

Why is controlling leakage current important?

Controlling leakage current is important for several reasons. Most electrical installations and equipment utilize grounding systems to protect against outages and hazards. In cases where there are faults or failures in the insulation between power lines and conductive parts, or the grounding connection is disrupted, current flow can cause a circuit breaker or a blown fuse. There is also a risk to human safety, particularly when using medical equipment.

There are standards in place to enhance safety and reduce risks. When using equipment and devices, it is critical to ensure that you are aware of permissible leakage current levels for the relevant application. It is important to note that limits are stricter and more rigorous for medical equipment.

Why medical power supplies need low leakage current?

Electrical equipment is increasingly commonplace within clinical settings. Electricity plays an essential role in enhancing treatment outcomes and saving lives, but using medical equipment can pose risks. Medical power supplies need low leakage current, and there are stringent guidelines in place. Medical equipment leakage current limits are significantly lower than non-medical equipment. This is a safety measure, which is used to protect both healthcare teams and patients.

In many parts of a hospital or healthcare facility, patients and staff are exposed to electrical currents, which have the potential to be fatal. Leakage current can pass through the human body either directly through the skin (this is known as macro shock) or through devices, supplies or equipment, such as pacemakers or catheters (this is known as micro shock). Electric shocks can be particularly hazardous for patients who are undergoing treatment in hospital, as they are likely to be more vulnerable.

What is the safety regulation on the leakage current of medical power supplies?

Medical power supplies are regulated using strict limits, which are considerably lower than equipment and devices used for non-medical purposes. This is to offer enhanced protection for patients and staff who are exposed to currents through the use of specialist medical equipment and devices.

Equipment that is intended for use within the medical industry must meet guidelines set out in the safety standard IEC -1. This is an internationally-recognized safety standard, which applies to any piece of equipment, which is connected to a mains power supply and used in the observation, diagnosis, treatment or management of a patient. Examples include:

• Heart monitors
• Blood pressure monitors
• Ultrasound equipment
• Laser technology for surgery

Under normal conditions, the leakage current limit for medical equipment is 10uA-500uA. This applies to a single fault condition. The table below outlines safety standards for different types of medical devices:

Leakage Current

Type B

Type BF

Type CF

NC

SFC

NC

SFC

NC

SFC

Earth Leakage current

500uA

1mA

500uA

1mA

500uA

1mA

Enclosure Leakage current

100uA

500uA

100uA

500uA

100uA

500uA

Patient Leakage current

100uA

500uA

100uA

500uA

10uA

50uA

If you are looking for more details, kindly visit leakage current monitor.

NC= Normal Conditions    SFC= Single Fault Conditions

Why choose FSP for low leakage medical power supplies?

FSP specializes in low leakage medical power supplies, providing equipment, which meets international safety standards and certifications. FSP’s medical power supplies include PC medical power supply, medical power supply adapter, open frame power supply and backup power for medical applications. With decades of experience in supplying clients with high-quality products and services, FSP is a leading name in the field of medical power supplies. If you have any questions, or you need advice about medical equipment, don’t hesitate to get in touch.

Summary

Leakage current is current that flows from an AC or DC circuit to the ground or another conductor. If the equipment or device is not grounded correctly, it is possible for current to flow through the human body. This is why it is vital to regulate and control leakage current for medical power supplies. Safety standards help to reduce risks and keep patients and healthcare providers and support staff safe.

Leakage current concept

Leakage current is a common electrical leakage phenomenon in electrical equipment. This phenomenon causes energy loss and causes electric current to escape out of the device's case, leading to the risk of incidents such as electric shock, electric shock, or even fire.

What causes leakage current?

Old electrical equipment: When equipment is used for a long time, components will gradually wear out and become damaged, increasing the risk of electrical leakage.

Placing electrical equipment close to a wall or in a humid environment: Placing equipment near a wall or in a place with high humidity can easily cause them to become damp, thereby causing electric leakage.

Improper installation and repair: When components are installed incorrectly or in the wrong order, the product structure may change, leading to electrical leakage at connection or joint locations.

External influences: Mice, insects or other pests can bite off electrical wires or damage internal components of the device, causing electric current to leak.

What leakage current level is safe?

Regulations on safe leakage current may vary depending on the purpose and conditions of use.

For medical equipment, leakage current standards are strictly managed because of the risk of causing electric shock to the patient. Normally, the maximum allowable leakage current level in the medical field is 0.5mA. Exceeding this level may pose a high risk to the user.

For common electrical equipment, the safe leakage current level is in the range of 0.7-3.5mA. For handheld devices, the limit is 0.75mA, while other devices can accept a maximum of 3.5mA.

Instructions for checking equipment for electrical leakage

To check for electrical leakage, you will need electrical measuring devices such as an electrical tester, clamp meter or multimeter.

Use an electrical tester

An electrical tester is a tool that helps detect electrical leaks quickly. You just need to bring the pen into contact with areas or devices suspected of having electrical leaks. If the pen glows, it indicates a leak and needs to be addressed immediately. Electrical testers such as Hioki's -20 or are good choices for performing this test.

How to use a multimeter to check for electrical leaks1 Another method is to check for electrical leaks with a multimeter. You will need a multimeter capable of measuring leakage current.

Below are the steps to check electrical leakage with a multimeter:

- Step 1: Connect the meter to the probe.

- Step 2: Put the meter into current measurement mode.

- Step 3: Choose the appropriate scale. If you are unsure about the level of electrical leakage, start from the highest measuring range and gradually decrease to protect the meter from overload.

- Step 4: Place the probe at the point to be tested in the circuit and read the results displayed on the screen.

Check leakage current with clamp meter

Some popular clamp meter lines for this purpose such as Hioki -10F and Hioki are options worth considering. Below are the steps to check leakage current with a clamp meter:

- Step 1: Disconnect the power source  

Ensure safety by shutting off the circuit breaker or disconnecting the power supply. Always keep your hands dry and use protective gloves to limit risks.

- Step 2: Unplug the devices  

Disconnect all electrical appliances in the test area such as televisions, refrigerators, microwaves, etc.

- Step 3: Prepare measuring equipment  

Start the clamp meter, use the jaws to clamp the device around the wire to be measured. Make sure both jaws of the clamp meter are clean and completely closed when measuring to obtain accurate results.

- Step 4: Check ground leakage current  

Perform measurements on single-phase circuits by clamping the jaws to the phase and neutral wires to detect ground leakage current. The device will display the level of leakage current present in the system.

Points to note when checking for electrical leaks

When you detect signs of electrical leakage, keep a safe distance and use protective measures to avoid risks. To perform the test safely, you need to note the following points:

- Keep distance and insulation: First, stay away from areas where there is suspected electrical leakage. Wear footwear with insulated soles to prevent electrical current from leaking to the ground, protecting you from the risk of electric shock.

- Use protective equipment: Wear rubber gloves and protective shoes before conducting the inspection. These items help you minimize the risk of exposure to electric current during operations.

- Avoid direct contact with the device: Do not touch the device directly with signs of electric leakage to avoid electric shock.

- Disconnect the power source before handling: To ensure maximum safety, disconnect the main power source before removing the problematic device from the system.

The above measures help ensure safety for inspectors and limit risks when handling electrical leaks in the system.

Tips for preventing and handling electrical leaks

To ensure safety, periodically use an electrical tester to check underground power lines. If a leak is detected, immediately disconnect the power source and carry out repairs to avoid danger.

In the event of a serious problem with underground wiring, such as a fire affecting the home's electrical system, you should consider switching to exposed wiring for easy monitoring. Or, if necessary, the wall can be drilled to replace damaged underground lines.

When installing a new electrical system, you should choose electrical wires with two layers of insulation to ensure safety. Make sure the installation process complies with technical standards, and use plastic pipes to cover the lines for protection. Plastic pipes should be highly durable, waterproof and have good strength.

Do not place the power outlet in places susceptible to moisture, as this may increase the risk of electrical leakage.

Conclude:

Above are my shares about the concept of leakage current, ways to check leakage current and notes when checking leakage current. You can refer to safe leakage current measuring devices at emin.vn, if If you have any questions, please contact us immediately for answers as soon as possible.

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