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What is the standard sound level (in dB) of Transformers of various kVA ratings?

Issue:
Sound level can be a factor when specifying Transformers

Product Line:
LV Transformers

Environment:
Applies to Low Voltage Transformers by SquareD/Schneider Electric

Cause:
Transformers of different kVA sizes can generate varying levels of sound when energized

Resolution:
Square D/Schneider Electric Transformers are built to standard sound levels listed in NEMA Standard ST-20. The transformers and corresponding sound levels per NEMA ST-20 are as follows . These can also be found in the Digest :

kVA <> NEMA standard sound level
0 - 9 <> 40dB
10 - 50 <> 45dB
51 - 150 <> 50dB
151 - 300 <> 55dB
301 - 500 <> 60dB
501 - 700 <> 62dB
701 - 1000 <> 64dB