Does back-feeding a low voltage dry type distribution transformer 15kVA or larger void the transformer's UL label?
Issue:
Is it recommended to back-feed a low voltage dry type distribution transformer, 15kVA or larger, or will it void the transformer's UL label?
Product Line:
LV Transformers
Environment:
Product Features
Cause:
Application.
Resolution:
Square D does not label its low voltage dry type distribution transformer`s terminals as primary or secondary, so backfeeding is not a violation of UL. The terminals are labeled as high voltage (H`s) or low voltage (X`s).
In the event that the primary voltage is identical to that of the secondary, the primary is marked high voltage (HV) and the secondary is marked low voltage (LV).
Square D does not recommend backfeeding transformers due the high inrush currents developed and the upstream protection tripping due to the inrush. There are precautions to be observed in backfeeding.
Is it recommended to back-feed a low voltage dry type distribution transformer, 15kVA or larger, or will it void the transformer's UL label?
Product Line:
LV Transformers
Environment:
Product Features
Cause:
Application.
Resolution:
Square D does not label its low voltage dry type distribution transformer`s terminals as primary or secondary, so backfeeding is not a violation of UL. The terminals are labeled as high voltage (H`s) or low voltage (X`s).
In the event that the primary voltage is identical to that of the secondary, the primary is marked high voltage (HV) and the secondary is marked low voltage (LV).
Square D does not recommend backfeeding transformers due the high inrush currents developed and the upstream protection tripping due to the inrush. There are precautions to be observed in backfeeding.
Released for: Schneider Electric USA
