Allowable Overvoltage Limit
Allowable Overvoltage Limit
(OP)
ANSI C84.1-1989 voltage tolerance limits specifies a maximum overvoltage of 218Y/126V for a 208Y/120V nominal base. Our system includes a 600V-208Y/120V transformer feeding a panelboard. Due to maximum demand loading at a worse case scenario, a primary tap of -2.5% is required to maintain the voltage drop at the 208V panelboard to within 3~4%. However, if I simulate a black start, on the 208V panelboard with minimum loading on the upstream system, the overvoltage on the panelboard bus is 105.8% which exceeds the 105% maximum imposed by ANSI C84.1-1989.
The 208Y/120V panelboard is feeding office loads and I have concerns during weekends when the loading is almost neglgible (all loads are shut-off).
Is there a way I can strike a balance or compromise?
The 208Y/120V panelboard is feeding office loads and I have concerns during weekends when the loading is almost neglgible (all loads are shut-off).
Is there a way I can strike a balance or compromise?






RE: Allowable Overvoltage Limit
RE: Allowable Overvoltage Limit
You could also replace your current transformer with one that has a lower tap.
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