jmbelectrical
Electrical
- Jul 16, 2011
- 126
I am involved in a project in which an existing building is being stripped and renovated in its entirety. Its incoming utility service is 480V, corner-grounded delta.
As the project is presently designed, we are stepping this down to 208/120Y and serving all of the building's loads via the 208/120V distribution system. Aside from serving the step-down transformer, the 480V side is mostly going unused. The size of the step-down transformer is increasingly becoming an issue, as the existing electrical room can only accommodate so much equipment. I am considering shifting some loads (A new elevator and some new HVAC equipment, in particular) to the 480V side of the distribution system, but I have some concerns.
I know that a typical three-phase load with a rated voltage doesn't "care" whether a voltage is line-to-line or line-to-neutral, so long as the voltage's value is correct. But what about equipment involving the use of VFDs, soft starters, and solid-state electronics? Is it safe to serve such equipment from a 480V, corner-grounded delta system? Or does a possibility exist that some component is going to be expecting a reduced line-to-neutral voltage, as would be the case in a Y-connected system?
Are there any other potential issues that I may not be considering?
As the project is presently designed, we are stepping this down to 208/120Y and serving all of the building's loads via the 208/120V distribution system. Aside from serving the step-down transformer, the 480V side is mostly going unused. The size of the step-down transformer is increasingly becoming an issue, as the existing electrical room can only accommodate so much equipment. I am considering shifting some loads (A new elevator and some new HVAC equipment, in particular) to the 480V side of the distribution system, but I have some concerns.
I know that a typical three-phase load with a rated voltage doesn't "care" whether a voltage is line-to-line or line-to-neutral, so long as the voltage's value is correct. But what about equipment involving the use of VFDs, soft starters, and solid-state electronics? Is it safe to serve such equipment from a 480V, corner-grounded delta system? Or does a possibility exist that some component is going to be expecting a reduced line-to-neutral voltage, as would be the case in a Y-connected system?
Are there any other potential issues that I may not be considering?