Electrical Design - Building Services

Explore how codes, standards, and specifications govern electrical design, ensuring safety and quality through national and international bodies like BIS, IEEE, IEC, NBC, NFPA.

Explore switchgear fundamentals, including circuit breakers, contactors, and releases, and learn how protection coordination, instantaneous and inverse time-delay settings, and pickup current govern safe, reliable switching.

Explore circuit breakers for fault protection, residual current devices, earth leakage protection, and current-limiting and microprocessor-based releases; learn discrimination, coordination, and rated performance concepts for reliable switchgear.

Transformers transfer energy via mutual induction between primary and secondary windings, stepping voltage up or down for transmission, with laminated cores, oil tanks, and copper, eddy current, and hysteresis losses.

Learn how a diesel engine drives a generator to convert mechanical energy into electrical energy via electromagnetic induction. Explore generator ratings, synchronization, loads shedding, and installation factors for emergency power.

Explore how capacitors store energy and shape signals, differentiate linear and nonlinear loads, and enable power factor correction and harmonic management in electrical systems.

Examine bus bar trunking systems with copper or aluminium conductors, sandwich and flat configurations, current ratings, safety advantages, and IP ratings for installation.

Learn the principal components of a conventional structural lightning protection system, including termination networks, down conductors, bonding, earth termination networks, air terminations, rolling spire method, and inspection, testing, and maintenance.

Understand luminaries general and emergency, including lighting fixtures, lamp fixtures, control fixtures, and luminance measurements. Explore downlights, recessed, pendant, landscape, and emergency lighting with battery backup and energy implications.

Learn to assess electrical switchboards, their degree of protection and internal separation, classify switchboards by category and type, and understand harmonics, power quality, and causes of distortion.

Compute the total connected load by summing lighting, plumbing (if present), and air conditioning loads per NBC standards. Lighting load uses room index, utilization factor, and maintenance factor.

Calculate the total connected load, add 10% for future use, apply diversity and demand factors, and account for motor starting currents to determine a safe transformer size.

Calculate total connected load, add a 10 percent future allowance, determine maximum demand with power factor and overload considerations to size a diesel generator.

Learn how to perform uninterruptible power supply sizing calculations by following steps and applying data from the table to determine the required UPS size.

Size a battery from nominal system using 110% (264) max and 90% (216) min; compute cell count from max allowable over cell voltage, apply 1.15 to max DC current.

Learn to size cables for building services using catalogs and de-rating factors, compute load current, verify carrying capacity, and choose copper or aluminium cables with runs for air and underground.

Calculate voltage drop in feeders using cable size, length, and catalog resistance and reactance; compare results to local limits, such as 3% for lightning loop and under 5% for loop.

Explore short circuit calculations to size circuit breakers using single-line diagrams, per-unit values, and maximum fault levels, enabling accurate fault current estimations.

Compute the tripping time and verify proposed cable adequacy against fault current by applying the given equations, site voltage ranges, and cable ratings for high and low tension installations.

Learn earthing calculations to size cables for 24 kA fault current, using copper, aluminium, and galvanized iron conductivities, while keeping earth resistance under 0.6 ohms and a 3-second breaker trip.

Apply bus bar sizing calculations by dividing the load current by the current carrying capacity of copper or aluminium bus bars to determine sizes.

Learn to determine cable tray sizes by calculating total cable diameters from catalog tables, adding space allowances, and selecting tray dimensions (width, depth, length) for multiple cable runs.

Develop skills in capacitor sizing calculations to design a capacitor bank that improves power factor from 0.8 to 0.99 for a 500 kW load, using available capacitor sizes.

Assess lightning protection needs using NFPA risk factors, yearly average flash density NG, building dimensions, location, and weighting factors. Determine whether protection is required based on the calculated overall risk.