Hello - I'm a retired EE who spent a career working in and around coal-fired electric generating plants. Nowadays I make my own electricity from the sun, while selling any excess back to the grid.
I came across this forum while googling for what the acceptable standards are for US household voltage. I found a couple of old threads and most seemed to indicate plus or minus 5% of 120 volts, but in my experience here in NE Ohio, my house sees over 130 volts quite often in the springtime, before my utility changes their xfmr taps for summer loads (at least, I think that's the explanation...). The reason for my search is that my home power system has grid-tied inverters that don't like it when the voltage on either 120 volt leg rises above 130.
I first observed this about 12 years ago after my first inverter install. At that time I enquired with the Ohio Consumers Council (a public consumer advocacy group) about it, and they told me the standard for us here was plus or minus 10%, which would allow voltages up to 132 volts and as low as 108.
Long story short, I recently installed an isolation transformer between the grid and one of my GTI's and set it up for 1:1 turns ratio, but now I'm considering changing that to 95% at the secondary, which would allow voltages as low as 103 volts.
I wonder if any of your forum readers would care to comment on acceptability of this low voltage? Not likely I'd see it much if at all, but...
Thanks in advance. - Mike
I came across this forum while googling for what the acceptable standards are for US household voltage. I found a couple of old threads and most seemed to indicate plus or minus 5% of 120 volts, but in my experience here in NE Ohio, my house sees over 130 volts quite often in the springtime, before my utility changes their xfmr taps for summer loads (at least, I think that's the explanation...). The reason for my search is that my home power system has grid-tied inverters that don't like it when the voltage on either 120 volt leg rises above 130.
I first observed this about 12 years ago after my first inverter install. At that time I enquired with the Ohio Consumers Council (a public consumer advocacy group) about it, and they told me the standard for us here was plus or minus 10%, which would allow voltages up to 132 volts and as low as 108.
Long story short, I recently installed an isolation transformer between the grid and one of my GTI's and set it up for 1:1 turns ratio, but now I'm considering changing that to 95% at the secondary, which would allow voltages as low as 103 volts.
I wonder if any of your forum readers would care to comment on acceptability of this low voltage? Not likely I'd see it much if at all, but...
Thanks in advance. - Mike
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