Distribution Transformers for Commercial Buildings
Because the substation usually sits inside or on top of the building, the transformer is specified as much for fire performance, noise and footprint as for its electrical rating.
Commercial buildings concentrate a lot of electrical load into a small footprint: chillers and HVAC, lifts and escalators, lighting, kitchens, IT rooms, tenant panels and standby generation.
Because the substation usually sits inside or on top of the building, the transformer is specified as much for fire performance, noise and footprint as for its electrical rating.
What Matters for This Application
- Fire and smoke regulation inside occupied buildings
- Noise limits for plant rooms near tenanted space
- Restricted access: basement loading, lift dimensions, rooftop lifting
- Heat rejected into the plant room affecting ventilation design
- Energy performance targets and green building certification
- Tenant fit-out changing the load profile over time
Recommended Transformer Solution
- Cast resin or VPI dry type transformer for indoor installation
- Low-noise design with anti-vibration mounting
- Class F or H insulation with forced air cooling for overload
- Compact, low-weight designs matched to site access limits
- Temperature monitoring relay with BMS alarm interface
- Low loss design to support energy and certification targets
Sizing Guidance
Commercial sizing uses demand factors per load type — HVAC, lighting, lifts, kitchen, IT — as set out in the applicable electrical code or consultant standard, then applies a diversity factor for the building as a whole.
Installation Notes
- Confirm fire separation, ventilation and access with the building's fire strategy
- Provide anti-vibration mounts and flexible connections to limit structure-borne noise
- Check plant room heat rejection against the ventilation design
- Integrate temperature alarm and trip contacts with the BMS
Testing and Commissioning
Before energisation the unit is checked on site: insulation resistance, voltage ratio and vector group, earthing and terminations, and functional checks of protection and monitoring devices. See the testing page for the full programme.