What is the Normally Permitted Motor Ratings as per DEWA?
Motor ratings are regulated by the Dubai Electricity and Water Authority (DEWA) to minimize starting current, voltage drop and system disturbance. The typically permissible motor ratings (without special approval or additional starting procedures) are shown below:
Normally Permitted Motor Ratings (LV – 415 V, 3-Phase)
1). Direct-On-Line (DOL) Starter
| Motor Rating | Permission Status |
|---|---|
| Up to 7.5 kW (10 HP) | Normally permitted |
| > 7.5 kW | Not permitted with DOL (approval required) |
Note: DOL starting draws 6-7 times the rated current resulting in voltage drops that are inappropriate for heavier motors.
2). Star–Delta Starter
| Motor Rating | Permission Status |
|---|---|
| 7.5 kW to 30 kW (10–40 HP) | Normally permitted |
| > 30 kW | Requires DEWA approval / justification |
3). Soft Starter
| Motor Rating | Permission Status |
|---|---|
| Up to 75 kW | Generally permitted |
| > 75 kW | Subject to DEWA study & approval |
4). Variable Frequency Drive (VFD / VSD)
| Motor Rating | Permission Status |
|---|---|
| Up to 150 kW | Normally permitted |
| > 150 kW | DEWA load study & approval required |
Note: VFDs are popular because they require less starting current and provide regulated acceleration.
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