Neutral and grounding wires are often confused outside of the electrical trade, since both conductors have zero voltage. Actually, if you connect the grounding wire as a neutral by mistake, most devices will operate correctly. However, such a connection is against code, since each conductor has a different function in an electrical installation.
The National Electrical Code (NFPA 70 NEC) establishes insulation colors for the neutral and grounding wires. Standard colors simplify an electrical installation, while making it safer.
- Neutral wire colors: White or grey
- Grounding wire colors: Green, green-yellow or bare
These insulation colors are only allowed for neutral and ground conductors, and using them for any of the live voltage phases is against the code. Electricians work with the assumption that wiring of these colors is at zero voltage, and using white or green insulation for a live conductor would be a deadly trap (and against code in the first place).
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Role of the Neutral Conductor in Electric Circuits
To visualize how the neutral conductor works, consider that electric power is delivered as current across a voltage difference. Voltage is carried by the live conductor, but a neutral conductor is also necessary for two important functions:
- Serving as a zero voltage reference point.
- Completing the circuit, providing a return path for the current supplied by the live conductor.
If only the live conductor is connected to an electrical device, it will not activate because current cannot circulate, regardless of the voltage applied. This is similar to how a hydroelectric turbine requires an outlet to produce motion: if the turbine discharge is blocked, water cannot flow and the turbine cannot rotate.
When an installation uses three-phase power, there may be cases in which the neutral conductor is not required.
- A three-phase system with a line voltage of 120V provides 208V between phases, and you can connect a 208V load between two phases without using a neutral wire. Both live conductors carry voltage, but current can flow because they have different voltages.
- Three-phase loads like electric motors are often designed to run with three live conductors and no neutral conductor. The same principle applies here: current can flow between live conductors at different voltages.
Even if some loads don’t use the neutral conductor in a three-phase installation, it is needed for single-phase loads that only use one of the line voltages. In theory, when identical loads are connected to the three phases, their currents cancel out and the neutral conductor carries zero current. However, this is unfeasible in real-life installations, and the neutral conductor carries the current imbalance between the three phases.
Role of the Grounding Conductor in Electric Circuits
The grounding conductor has zero voltage just like the neutral conductor, but it accomplishes a different function. As implied by its name, this conductor provides a grounded connection for all appliances and equipment.
- Under normal conditions, all current returns through the neutral conductor, and the grounding conductor has no current.
- When a line fault occurs, the grounding conductor provides a return path for the fault current. Electrical protection devices can detect this condition, and they immediately disconnect the circuit from the power supply.
Without a grounding connection, appliances and equipment become energized if a live wire touches them accidentally. The fault is not disconnected, since protection devices can only respond when there is a fault current in a grounding wire. In this case, anyone who touches the energized surface will suffer an electric shock.
Since a ground fault can affect any circuit, the grounding conductor is required even when there is no neutral wire. For example, if a motor uses three live conductors and no neutral, grounding is still required because any of the live wires can cause a fault.
Sizing Neutral and Grounding Conductors Correctly
Live conductors are sized for the current they are expected to carry, and the same applies for neutral conductors in single-phase circuits (they carry the same current as the live wire). However, different rules apply for three-phase circuits: a common practice is using the same wire size as the phase conductors, but some applications require a larger wire size for the neutral conductor.
- Grounding conductors for branch circuits are sized based on the capacity of the overcurrent protection device, using tables provided in the NEC.
- On the other hand, grounding conductors for the main service entrance are sized based on the capacity of service conductors. The NEC provides tables for both cases.
By working with qualified electrical engineers from the start of the project, you can rest assured that all components are specified according to the NEC and local codes. This not only provides safety, but also a quick project approval with local authorities. Electrical engineers can also suggest energy efficiency measures to save on power bills.
Why Hire Electrical Engineers To Handle Development Projects
When you’re developing a real-estate or office project, you need to get everything ready for what your future tenants will need. From an HVAC system to an optimal energy plan, you’re better off hiring professionals than going with cheaper solutions. Our teams of electrical engineers are very familiar with the entire construction process and will always come up with the best solution for your building. Electrical engineering design is no simple task.
Hiring Electrical Engineers Will Ensure the Success of Your Project
Electrical engineering is an essential part of every residential development project. You want your building to follow all of the legal guidelines, and our electrical engineers will help you do just that. Networks are complex and must be able to sustain all of your equipment and facilities. A team of professional contractors will design and install a network that’s tailored to your building’s specific needs, ensuring that your activities can go on without any hitches.
Electrical Engineering Design that Saves You Money
Your building’s electrical circuits are the cornerstone which supports your activity. Whether you need to support specialized equipment, office equipment, heating, ventilation, water pumps, we can help you save money in the long haul. With the constant surges registered on the energy markets, having professionals to provide a design that minimizes costs is definitely the way to go.
New York Engineers has you covered. We have professionals trained in every field, so we have the knowledge that’s required in designing feasible, low-maintenance electrical engineering projects.
What Makes Us Different From Other Firms
We know that your time and money are valuable. That’s why we provide you with accurate estimates and a very quick design proposal. You’ll be getting an estimate in less than 24 hours after requesting for one. We do our best to stay within the original estimate, and we make sure to finish our projects as fast as possible. Some people work smart, some people work hard. We do both.
Something as trivial as a 24-hour delay can mean huge shifts in your budget. That is why we guarantee that our design process is 50% faster than anything else you can find in the industry.
We Keep You in the Loop
Our professionals will keep you constantly informed in regards to the project’s development, possible delays, anything that you’d want to know about. Any questions that you have will be answered by someone who is up to speed and working within the development team.
Take the First Step and Reach Out for a Free Estimate
If you’re on the ropes, then our free estimate should put your worries to rest. Our teams of electrical engineers are sure to send you an accurate initial cost and help you understand your future building’s electrical needs. Save money, and work with a team of dedicated professionals who will keep you informed every step of the way.