Building Electrical Installation Design Principles

Principles of Electrical Installation Design for Building

To design electrical systems for buildings, many elements must be considered. In the first phase, the design or style of energy distribution in the building should be decided. Despite the presence of numerous kinds of structures, the design criteria for electrical installations are an important procedure with practical implications. The architectural style of energy distribution has a considerable influence on the efficiency and longevity of electrical infrastructure.

The influence of these decisions starts with the construction of electrical infrastructure. Important concerns during execution include installation implementation time, task execution rate or efficiency, and needed team qualifications, among others. The technique of energy distribution used has an impact on the performance of installations while they are in operation. Important operational considerations include the quality and continuity of providing sensitive loads, losses, and so on. The kind and execution of electrical systems should be examined when recycling them after the end of their useful life. The procedures for selecting an architectural style in energy distribution are as follows:

1. Configuring or determining the space and position of equipment.
2. Identifying and describing various distribution levels.
3. A single-line diagram
4. Selection of Equipment

Electrical installation standards in buildings must be properly evaluated. This section explains 12 critical design factors for electrical systems in buildings. These features are critical for determining the principles and specifics of the architecture of electrical energy distribution. Each aspect will be explained, classified, and given potential values.

What You’ll Read In This Article: Principles of Electrical Installation Design for Buildings

1. Scope of Activity
2. Site/Complex Structure
3. Plan Extent
4. Reliability of Service
5. Maintenance Capability
6. Flexibility of Electrical Installation
7. Required demand
8. Load distribution
9. Sensitivity of installations to voltage interruptions
10. Sensitivity to Disruptions in Power Source
11. Potential or ability to disrupt circuits
12. Other Significant Factors and Constraints

1. Scope of Activities:

Buildings are planned and built to accommodate their intended use or activities. The kind of activity has a considerable impact on electrical installation design principles. This section describes the definitions contained in IEC 60364-8-1 Standard Section 3.4.

• Residential Building: A structure planned and built for private dwelling.
• business Building: Spaces developed and constructed for business purposes. Commercial buildings include offices, retail areas, distribution centres, public buildings, banks, and hotels.
• Industrial Building: Sections planned and constructed for manufacturing or particular procedures. Industrial buildings include factories, workshops, distribution centres, and assembly plants.
• Organisational and Infrastructure Buildings: Industrial and transportation facilities. Airports, ports, railroad stations, and other transportation hubs.

2. Site/Complex Structure:

This section describes the architectural aspects of the building or structures. Key characteristics are the number of buildings, the number of levels, and the size of each floor. Increasing the number of storeys challenges the layout of electrical infrastructure. For example, crucial design features for electrical systems in a single-floor structure vary dramatically from those in high-rise buildings or skyscrapers. Some categories include:

• A single-story building
• A multi-story building
• Site with many buildings.
• High-Rise Buildings and Towers

3. Plan Extent:

Electrical equipment cannot be placed and utilised in every area of the building. Paying attention to these limits is an important factor throughout the design process. Important considerations to consider while deciding the location of electrical equipment in the structure are:

• Aesthetic
• Accessibility.
• Presence of certain spaces.
• Use installation corridors on each floor.
• The use of vertical channels or ducts.

Different categories include:

• Low: The position of electrical equipment is fully stated.
• Medium: The position of electrical equipment is considerably restricted to avoid harm.
• High: There are no limits, and the location of electrical equipment may be decided to ensure compliance with rules.

4. Reliability in Service

Reliability in service refers to a power system’s ability to function under particular circumstances throughout a given time period. When planning electrical systems for buildings, consider the various degrees of dependability. There are several categories in this field, including:

• Minimum: This degree of dependability suggests a possibility of interruption due to geographical, technological, or economic limits. Geographical restrictions might include a separate network and a distance from the manufacturing centre. Technical restrictions may include inadequate overhead wires or a faulty ring or loop system. Economic restrictions may include low maintenance and tiny size or requirements.
• Standard.
• Advanced: This level of dependability includes extra efforts to limit the likelihood of outages. Underground lines, a strong ring or mesh network, distinctive design, the installation of emergency generators, and so on are all examples of risk reduction techniques.

5. Maintenance Capability:

Maintenance capability refers to the placement of specified characteristics during the design of electrical infrastructure. These characteristics mitigate the effects of repairs and maintenance on the performance of a segment or the whole system. Classifications of repair and maintenance capacity include:

• Minimum: To perform repairs and maintenance at this level, the whole system must be halted or de-energized.
• Standard: Repairs and maintenance may be undertaken while the installations are operational, although at a reduced capacity. In this instance, scheduled repairs and maintenance should be carried out at certain times, such as low-load hours or decreased routine activity. Consider a system having many transformers that may be connected in parallel. In this setup, one of the transformers may be removed from the circuit and serviced under a low-load condition.
• Advanced: With particular design activities, operations, servicing, and maintenance may be carried out without worry or disturbance to other portions. Configurations with double-sided electrical installations, for example, are an option.

These principles serve as a basis for designing electrical systems in buildings, taking into account a variety of elements that influence performance, dependability, and simplicity of maintenance. Each concept is essential in developing a system that suits the building’s particular demands and activities while maintaining safety and efficiency.

6. Flexible Electrical Installations

Flexibility in the electrical system refers to the capacity to reposition energy delivery points or boost power supply in certain portions of the installation. For example, it should be simple to branch a piece of the system or enhance the current flow in a branch. Flexibility is an important quality in the early phases of a project because of uncertainties in the construction and electrical infrastructure. The degree of flexibility in electrical systems is classified into the following groups:

• No Flexibility: In these structures, load locations are fixed throughout their entire cycle. These limits might develop for a variety of reasons, including the construction of the building, the high voltage line path, or the manufacturing process. For example, equipment in melting lines is thought to be rigid.
• Flexible Design: In this system, the number of energy delivery points or branches, power level, and load placement are not fixed.
• Flexible Implementation: Flexible implementation is the process of installing loads after the installations have been commissioned.
• Flexible Operation: The load locations in these installations alter when the process is reorganised. For example, in industrial structures, growth, partition into parts, and changes in use may necessitate the shifting of loads. In office buildings, this procedure involves separating vast hallways or rooms into smaller parts. To view hundreds of additional specialised articles, visit the Medium Voltage Electrical Installations Design area.

7. Required Demand

The word necessary demand refers to the maximum active and visible electrical power required by a building’s electrical systems, which is defined by its size. For further details, please see the article How to Calculate the Electrical Consumption of a House or Chapter A, Section 4. The demand classifications based on perceived power are as follows:

• Less than 630 KVA
• Between 630 and 1250 kVA.
• From 1250 to 2500 kVA
• More than 2500 kVA.

8. Load Distribution

This feature refers to the homogeneity of load distribution in terms of kVA per square metre in a sector or across the structure. Information on load distribution is critical for determining the needed demand for electrical infrastructure. Load distribution may be classified as follows:

• Uniform Distribution: Each load unit has moderate or low power and is dispersed across a big area or the whole structure. These loads, such as lighting or particular work systems, have a constant density across the facility.
• Medium Distribution: Loads in this system are generally of moderate power and distributed throughout the structure. Medium load distribution includes assembly line equipment, conveyors, workstations, logistics modular sites and so on.
• Local Loads: Local loads are often high in power and spread unevenly across the building. Ventilation systems are instances of local load.

9. Sensitivity to voltage interruptions.

This section classifies circuit groups depending on the permissible period for voltage interruptions.

• Removable or Reducible Circuit: Loads in this circuit may be detached at any moment and for an indefinite period.

• Circuit with Long Disconnect Capability: Loads in this category have a disconnect capability of more than three minutes.

• Circuit with Short Disconnect Capability: The power supply to these circuits may be terminated in less than three minutes.

• Non-Disconnectable Circuits: These circuits and their associated loads should never lose power. According to the [EN50160 standard], the time length might be less than or more than 3 minutes. This standard specifies the characteristics of voltage or power sources obtained from public distribution networks. Voltage disruptions in each circuit may have a variety of outcomes. Electrical circuits and loads linked to them are also classified according to the damage caused by power outages. These categories include:

• There is no significant damage

• Production Loss

• Production Equipment Damage or Critical Information Loss

• Fatal Consequence The mentioned categories of time and damage caused by power source disruptions may be combined. In electrical systems, the relevance of power source disruptions is often divided into four categories:

• No Priority: Loads or circuits without priority may be terminated at any moment. For example, turning off the electricity to the water heating system has no difference.

• Low Priority: Disconnecting low-priority loads or circuits can cause momentary displeasure among building occupants and may impede productivity or efficiency if the disruptions are extended. Circuits that feed heating, cooling, and HVAC systems are considered low-priority.

• Medium Priority: Disconnecting medium-priority circuits will have a significant cost effect and disrupt operations or services. These circuits have a maximum permitted duration for power outages. Extended downtime in the power supply for medium-priority loads may have economic effects, such as lost output or the cost of restarting lines. Refrigeration, freezers, and lifts are some examples of medium-priority loads in buildings.

• High Priority: Power outages pose life-threatening threats and intolerable cost effects for high-priority loads. Medical facilities, information technology, and security are among the highest priority loads.

10. Sensitivity to disturbances in power supply

Sensitivity to disturbances refers to a circuit’s capacity to perform normally under specified situations. Power supply interruptions may cause a variety of improper performance modes. Disruptions in power supply may cause process stalling, erroneous operation, lower equipment lifetime, higher losses, and so on. Circuits may be classified into the following classes depending on their proper functioning under power supply disturbances:

• Low Sensitivity: Variations in the power supply voltage have minimal effect on the performance of these loads. For example, a heater falls within the low-sensitivity category.
• Medium Sensitivity: Voltage disruptions cause severe damage or injury to these loads. Motors and lighting systems fit under this category. Voltage fluctuations in these loads produce damage over time, rather than all at once.
• High Sensitivity: Voltage disturbances in this group result in process shutdowns or full equipment failure. Computers and other information technology equipment, for example, are sensitive to substantial disruptions. The amount of sensitivity of loads to power disturbances is an important consideration in circuit design. The system’s sensitivity determines the number of shared or dedicated circuits. It is advised to employ load grouping while designing electrical facilities. In fact, it is preferable to segregate sensitive loads from those that cause disruptions. For example, you may separate lighting and motor circuits. The separation of circuits is also determined by operating parameters. The separation of circuits allows you to monitor and analyse the power consumption or demand of each group separately.

11. Potential or Capability of Disrupting Circuits

Loads attached to a circuit may interfere with the functioning of adjacent circuits and equipment. Harmonics, inrush currents, imbalance, high-frequency currents, magnetic field emissions, and other phenomena may all cause circuit disruptions. Circuits are classified into the following classes based on their capacity to produce interference with the functioning of other equipment:

1. No Disturbances:

• These loads do not cause interference and do not need any protective or preventative actions.

2. Medium to Occasional Disturbance:

• If there are sensitive or highly sensitive loads, the circuit and power source may need to be separated. For example, lighting circuits that generate harmonics should be segregated from other portions.

3. Severe Disturbance

• To provide high loads, specialised circuits and interference-reducing technologies must be utilised in installations. Electric motors with high beginning currents and welding equipment with varying currents should be powered separately.
• To manage motor inrush current, different soft starters and drives may be employed. It is crucial to note that soft starts do not generate harmonics; nonetheless, drives must be managed in this respect. Large drives, or the presence of several drives in a circuit, may produce harmonics. If drives create harmonics, a variety of chokes and reactors should be employed.

12. Other Important Factors and Constraints

The characteristics stated thus far are present in most electrical setups and are very prevalent. When constructing electrical systems for a building, it is important to consider certain limits and situations. Some of these criteria are:

• Building-specific restrictions, such as those for hospitals and high-rise structures.
• Regulations governing distribution firms, such as limitations on connecting to the LV network and access to the MV substation.
• Load connections, such as connecting two heavy loads to different circuits for better current management and operating efficiency.
• The designer’s ability to match the intended system with past instances via the use of standardised subsets, installation bases, or equipment utilisation.
• Power supply constraints, including voltage levels and energy delivery systems. The voltage may be 230, 400, or 690 volts, and it can be delivered in buildings that use single-phase, two-phase, three-phase with neutral, or three-phase without neutral systems.

Conclusion:

The process of choosing architecture begins with the original design of the building’s electrical infrastructure. This process includes the primary distribution of medium and low pressure, low-pressure energy distribution, and terminal distribution. In buildings, all loads are wired to low-pressure circuits. Given the lack of MV consumers in the building, the medium-pressure energy distribution network is only implemented in the following sections:

• Connect to the distribution company’s network to get electricity.
• An internal network that distributes medium-pressure energy between substations.
• Substations that operate at medium pressure.

The factors listed above are intended for gathering information before planning electrical systems in buildings. The basics of planning electrical systems will be discussed more below.