7.2 Electrical Systems & Illumination Design

7.2 Electrical Systems & Illumination Design

Quick Answer: Detailed electrical system design belongs to a licensed Professional Electrical Engineer (PEE) working under the Philippine Electrical Code (PEC), but the ALE tests an architect's coordination fluency: where the service entrance lands, how panelboards and circuits shape floor plans, and - squarely an architectural responsibility - how illumination design balances daylight and artificial light against the lux level a space's function demands and the energy limits of the Green Building Code of the Philippines.

The Governing Code and Standard Service Voltage

The Philippine Electrical Code (PEC), currently in its 2017 edition, sets the wiring, protection, and equipment rules for every occupancy type. Most residential and small-commercial services in the Philippines run on a standard secondary voltage of 230 volts, single-phase, supplied by the local distribution utility (Meralco in Metro Manila and analogous utilities and electric cooperatives elsewhere). Larger loads - commercial buildings, condominiums, industrial facilities - typically take three-phase, four-wire service at 230/400 volts, which lets the design split loads across phases for efficiency and balance.

Service Entrance and Distribution: What the Architect Must Reserve Space For

The service entrance is the physical and electrical path from the utility's point of delivery (the revenue meter) to the building's main distribution board (MDB). On a residential lot this is often a simple meter pedestal and a short conduit run; on a mid-rise or high-rise project it becomes a design problem the architect must solve early:

• A meter room or meter bank accessible from the property line for utility reading and maintenance, without requiring utility staff to pass through private units.
• A main electrical room or transformer/switchgear vault, usually at the ground floor or basement, sized and ventilated for the incoming service equipment and sited away from water sources (cisterns, drainage lines) that could flood it.
• Vertical electrical risers/shafts running from the main room to floor-level panelboard closets, planned alongside - never inside - plumbing and fire-protection shafts.

Skipping this early reservation is one of the most common causes of redesign once a project reaches the engineering-design phase, which is why the ALE treats it as a utilities-coordination topic rather than a pure electrical-engineering one.

Panelboards and Circuiting Basics

From the MDB, feeders run to panelboards (also called load centers) distributed by floor or by zone, each panelboard breaking power down into branch circuits - the wiring between the final overcurrent protective device (a circuit breaker) and the outlets or equipment it serves. The PEC requires that a lighting-and-appliance branch-circuit panelboard carry overcurrent protection no greater than 30 amperes per branch circuit of that class, and that conductors be protected according to their ampacity rating. For the architect, the practical implication is that circuiting logic drives closet and wall space: panelboard closets need clear working clearance in front of the panel door (a PEC life-safety requirement, not just a convenience), and circuit counts scale with the number and type of loads - general lighting, convenience outlets, and dedicated circuits for air-conditioning units, water heaters, and kitchen appliances all typically require separate branch circuits.

Illumination Design Principles

Illumination level is measured in lux (lumens per square meter) or, in older Philippine references, footcandles (1 footcandle is approximately 10.76 lux). Occupational illumination standards commonly cited in Philippine practice set general targets by task and space type:

The architect's role is not to select every fixture's wattage but to make sure the room geometry, ceiling height, and finishes can deliver these targets - a deep, narrow room with a low, dark ceiling forces artificial lighting to work far harder (and consume more energy) than a shallow, light-finished room with good daylight penetration.

Daylighting and Window Design

PD 1096 Rule VIII requires that any room not served by mechanical ventilation and artificial lighting systems have window openings totaling at least 10% of the room's floor area, and never less than 1.00 square meter - a rule that ties directly into daylighting strategy, since a compliant window is also the room's primary daylight source. The Green Building Code of the Philippines pushes this further, directing designs to maximize daylight harvesting through windows, light shelves, clerestories, and skylights, so that interior perimeter zones need little or no artificial lighting during the day. Where daylight is harvested for energy savings, the code expects daylight-controlled lighting systems - photoelectric sensors that dim or switch off luminaires when daylight is sufficient - paired with occupancy sensors that override the photoelectric control so lights don't stay off in a still-occupied but dim room.

Energy-Efficient Lighting Strategies

The Green Building Code caps Lighting Power Density (LPD) - the installed lighting wattage per square meter of floor area - using the 2010 PSVARE Standards referenced in its Table 11. Two figures worth remembering for the exam: a maximum of 10.8 W/m2 for business/office space and 12.9 W/m2 for educational (school) space. Meeting these caps in practice means specifying efficient LED sources, pairing daylighting with sensor controls, and designing fixture layouts that avoid over-lighting spaces beyond their functional lux target - every watt above the functional need is wasted energy and, in a tropical climate, added air-conditioning load from the extra heat the fixture generates.