DEWA Electrical Requirements for Facade Lighting in Dubai

What DEWA tariff applies to facade lighting?

Facade lighting is billed under the building's primary DEWA tariff classification — there is no separate facade lighting tariff — with commercial rates following a progressive slab structure from 23 fils/kWh to 38 fils/kWh plus fuel surcharge and demand charges.

The slab structure makes energy efficiency directly financial. A 40-story tower consuming 15,000 kWh/month for facade lighting at Slab 4 rates pays 6,675 AED/month (38 + 6.5 fils × 15,000). Reducing consumption by 35% through Al Sa'fat Platinum scheduling and high-efficacy fixtures drops consumption to 9,750 kWh/month — saving 2,340 AED/month or 28,080 AED/year. Over a 10-year fixture lifecycle, the cumulative saving (280,800 AED) typically exceeds the capital cost premium for the higher-specification system.

Does facade lighting require separate metering?

DEWA does not require separate utility-level metering for facade lighting, but Al Sa'fat Gold and Platinum tiers require internal sub-metering at the distribution panel level for energy monitoring and compliance reporting.

Sub-metering uses current transformer (CT) based energy meters installed on the facade lighting circuit breakers within the building's main distribution panel or sub-distribution panel. The meters connect to the building management system (BMS) via Modbus or BACnet protocol, providing real-time and historical energy consumption data. This is internal building infrastructure — not a DEWA meter — and does not require a separate DEWA account or connection application.

The sub-metering data serves three purposes: Al Sa'fat annual compliance verification, internal energy cost allocation (assigning facade lighting costs to the correct cost center in multi-tenant buildings), and system performance monitoring (detecting anomalies that indicate fixture failure, control system malfunction, or scheduling override).

How should facade lighting circuits be separated?

Facade lighting circuits must be electrically separated from life-safety circuits (emergency lighting, exit signs, fire alarm) and from general power circuits, served from dedicated circuit breakers in the distribution panel with clearly labeled identification.

DEWA's Distribution Regulations mandate separation for three reasons:

• Maintenance isolation. Facade lighting must be isolatable for maintenance without affecting any other building system. A dedicated circuit breaker allows complete de-energization of facade circuits while life-safety and general power continue uninterrupted.
• Scheduling control. Separated circuits enable clean contactor or relay-based switching under smart control systems. Mixed circuits prevent clean zone-based scheduling.
• Fault containment. A short circuit or ground fault in facade lighting wiring (which is more exposed to environmental damage than interior wiring) must trip only the facade lighting circuit breaker, not cascade to life-safety or general power circuits.

What are DEWA's earthing requirements for exterior lighting?

DEWA requires all exterior lighting installations, including facade lighting, to be connected to the building's main earthing system with a maximum earth impedance of 1 ohm — verified by measurement during commissioning and recorded in the completion test certificate.

Earthing for facade lighting involves three paths:

• Circuit protective conductor (CPC). A dedicated earth conductor (green/yellow) within the supply cable to each fixture, sized per BS 7671 Table 54.7 (minimum 1.5mm² for cables up to 16mm², equal size for larger). This provides the primary fault return path that triggers the circuit breaker on earth fault.
• Fixture body bonding. Metal fixture housings must be bonded to the CPC at the terminal block. Fixtures with Class I construction (metal body, earth terminal) require this connection. Class II fixtures (double-insulated, no earth terminal) do not require body bonding but are relatively rare in high-power facade applications.
• Supplementary bonding. On buildings with metallic facade systems (aluminum curtain walls, steel structures), the facade framework itself must be bonded to the main earthing system. All fixture mounting brackets in contact with the metallic facade create potential fault paths that must be controlled through deliberate bonding rather than incidental metal-to-metal contact.

What power quality standards affect LED facade lighting?

DEWA's Grid Code requires all connected loads to maintain a power factor above 0.85 lagging and total harmonic distortion (THD) below 10% — requirements that affect LED driver specification because poor-quality drivers may introduce harmonic distortion that exceeds these limits.

LED drivers are non-linear loads that draw current in short pulses rather than smooth sine waves, generating harmonic currents that distort the supply waveform. High-quality drivers incorporate active or passive power factor correction (PFC) that reshapes the input current to closely follow the voltage waveform, achieving power factors of 0.95 to 0.99 and THD below 10%. Low-quality drivers without PFC may have power factors as low as 0.50 and THD above 30%, which violates DEWA requirements and creates operational problems including overloaded neutral conductors, transformer heating, and tripped protection devices.

For the complete LED driver specification including power factor, THD limits, and DEWA-compliant surge protection ratings, see the LED technology section. For cable sizing and installation requirements that complement DEWA circuit standards, see the installation guide.