What is the reason for the neutral wire not touching the ground in a circuit?

In a circuit, the reason why the neutral wire is not grounded is mainly related to the design of the circuit, safety, and the way the system operates. Here are some common reasons:

Prevent current leakage

• Current balance: In a three-phase system, if the neutral line is grounded, it may cause current imbalance, which affects the stability of the system.

• Prevent current leakage: If the neutral wire is grounded, when the system fails, a current loop may be formed through the grounding system, resulting in unnecessary current leakage.

Improve security

• Avoid misgrounding: The neutral line is not grounded to avoid the risk of short circuit caused by misgrounding.

• Protection equipment: For some equipment, neutral grounding may cause damage or abnormal operation of the equipment.

System design requirement

• System design: The design of some electrical systems requires that the neutral line is not grounded to meet specific functional requirements.

• Voltage stability: The neutral line is not grounded can help maintain the voltage stability of the system, especially in some occasions with high voltage requirements.

Circuit types and applications

• Single-phase system: In a single-phase system, the neutral line is usually used to return the current, and not grounding can avoid the current forming a closed loop through the grounded system.

• Three-phase system: In a three-phase system, the role of the neutral line is to balance the current between the phases, and ungrounded can avoid the imbalance introduced by grounding.

Avoid interference

• Electromagnetic interference: Neutral grounding may introduce electromagnetic interference, affecting the normal operation of the system.

• Signal interference: In some sensitive electronic devices, neutral grounding may cause signal interference.

Follow standards and specifications

• National standards: Different countries and regions have different regulations for the grounding of electrical systems, and in some cases, the neutral line is not grounded.

• Industry standards: Electrical system design standards in some industries require that the neutral line be ungrounded.

Avoid voltage drift

Voltage reference point: The neutral line is not grounded to maintain voltage stability and avoid voltage drift caused by grounding.

Protect personal safety

• Avoid electric shock: Grounding the neutral wire may cause the device housing to be charged, increasing the risk of electric shock.

• Reduce the risk of faults: The neutral line is not grounded to reduce the risk of faults caused by poor grounding.

Illustrate by example

Single-phase system

In a single-phase system, the neutral line is usually used to return the current, and being ungrounded prevents the current from forming a closed loop through the grounded system. For example, the neutral line in a home electrical system is usually not grounded, but grounded through the neutral point.

Three-phase system

In a three-phase system, the role of the neutral line is to balance the current between the phases, and ungrounded can avoid the imbalance introduced by grounding. For example, in industrial power systems, the neutral line of a three-phase system is usually not grounded to maintain the voltage stability of the system.

Sum up

The reason why the neutral line is not grounded is mainly to prevent current leakage, improve safety, meet system design requirements, avoid interference, follow standards and specifications, and protect personal safety. In practical applications, whether grounding needs to be determined according to the specific circuit type, application occasions, and national and industry standards. Ensuring the safe and stable operation of the electrical system is a primary consideration. If you have specific application scenarios or technical problems, it is recommended to consult a professional electrical engineer or technical personnel.