Low Voltage Electrical Systems and Material Science

REBT and Low Voltage Electrical Installations

REBT refers to the technical conditions that must be met by electrical installations connected to a low voltage supply.

Components of the Installation Link

• General protection box: This includes host protection elements such as fuses.
• General line supply: This connects the protection box with the centralization of the building counters.
• Counter (Meter): A device designed to measure the electrical energy consumed by the subscriber.
• Individual referral: The electrical line that joins the counting team to the main distribution panel.

Interior Installation and Control Panels

The interior installation is divided into the main panel and the feeding and earthing circuits. The panel includes:

• ICMP: Maximum power control.
• ID: Detects leakage current.
• PIAs: Switches that separate different circuits within the house.

Electrical Command and Control Devices

These are operators that govern electrical circuits:

• Switches: Feature two stable positions (ON / OFF).
• Push buttons: Feature one stable position (normally open [NO] or normally closed [NC]).
• Commutators: Switches that toggle between one circuit or another.
• Crossover switches: Used for turning lights on or off from more than two locations.
• Other devices: Includes teleruptors and electronic door systems.

Home Automation and Domotic Systems

Home automation involves the automation and control facilities of a housing unit.

System Elements and Classification

• Elements:
  • Sensors: Capture information such as temperature or smoke.
  • Actuators: Execute actions like heating or alarms.
  • Drivers: The domotic controller that manages the system.
• Classification: Systems can be centralized (most common), distributed, or mixed.

Applications of Domotics

• Energy management: Control of heating and lighting.
• Comfort: Automation of irrigation and lighting.
• Security: Alarms and leak detection.
• Communications: Internet integration.

Electricity Pricing and Technical Formulas

Pricing is set by the BOE (Official State Gazette) through different rates. Technical calculations for light bulb rows and circuits include:

• Power: P = V · I
• Resistance: R = P / I²
• Voltage: V = P / I
• Energy: W = V · I · t

Material Selection Criteria and Properties

When selecting materials, designers consider physical properties, aesthetics, manufacturing processes, cost, availability, and environmental impact.

Mechanical Properties and Stress Types

Mechanical resistance is the ability of a material to resist efforts without breaking. To support greater effort, a larger section must be applied. Types of effort include:

• Tensile: Stretching.
• Compression: Crushing.
• Flexion: Bending.
• Torsion: Rotating.
• Shear: Cutting.

Deformation and Material Behavior

• Elastic deformation: The material recovers its original form when the effort ceases.
• Plastic deformation: The deformation is permanent.
• Fragile: Breaks with minimal deformation.
• Ductile: Supports significant deformation before breaking.

Key indicators include E (stiffness or elasticity) and σt / σe (mechanical resistance and plasticity).

Hardness, Tenacity, and Testing

• Hardness: Opposition to surface penetration. Calculated via the Brinell hardness test or using a diamond drive.
• Tenacity: Ability to resist shock. Measured via resilience testing and fatigue testing.
• Non-destructive testing: Includes magnetic testing and radiation testing (X-rays and Gamma rays).

Engineering Formulas

Calculations for stress and area:

• Stress (σ): F / A
• Area (A): π · r² (where r = diameter / 2)
• Units: N/mm² (MPa)
• Yield/Tensile Strength: σe or σt