What is the normal practice in the absence of a wattage rating for IT equipment?

In the context of IT equipment, utilizing VA (volt-ampere) ratings for load sizing is considered best practice when there's no wattage rating available. The VA rating measures apparent power, which combines both real power (kW) and reactive power. It is particularly relevant for IT equipment, which often has motors or electronic components that can create a phase difference between current and voltage.

By using the VA rating, one can effectively estimate the electrical load that the equipment will impose on the system. This approach allows for appropriate sizing of circuits, breakers, and backup power systems, ensuring they can handle the load efficiently and safely.

In contrast, estimating wattage based solely on voltage may not account for the specific characteristics of the IT equipment, and configuring all equipment for maximum load could lead to inefficiencies or unnecessary expenses in power supply infrastructure. Relying solely on kW ratings without considering VA ratings can result in underestimating the actual power requirements, especially for equipment with different power factor characteristics. Thus, using VA ratings ensures a more accurate and safer approach to load sizing for IT equipment.