Isolation transformers output voltage higher than wall

Hi @cleeds - I think the difference between your numbers and mine is service (what the power company provides) vs. voltage at the outlets, no? The minimum acceptable voltage at the outlets I believe is therefore lower, as I interpret the data on the link site. Still, we are not in disagreement that the max is 126 VAC.

The difference is that the NEC allows for a certain amount of sag in the household.

@jc4659 Depends how fancy you want to get. Ideally the two are combined, so the isolation transformer and the AVR are the same transformer. Makes for less power loss and higher efficiency. The best place for a voltage regulator otherwise is after any isolation transformers.

I think it’s most important to isolate cheap wall warts and digital supplies. So put any Ethernet, Roku, gaming appliances outside your clean zone.

Hey,

Trannies often are wound so the input to output is a little more than 1 to 1 when no load is applied. This is to compensate for inefficiencies that happen under load.

That is, with no connected devices it’s 1:1.05 but when the load is applied the output voltage will drop to around 1:1.

Acceptable AC voltage range in the US is 110V to 126V.

I have been in an apartment in San Francisco with 130V and PG&E did rebalance their loads to bring that down in a couple of weeks.  They said it was safe but not ideal.

Personally I notice a daily variance of 15V and use a voltage regulator as the front end of my audio conditioner chain. This happens even without the stereo being on or the heat pumps engaged. The VR keeps my voltage consistently between 117 and 122, regardless of the appliances or stereo state.

https://amzn.to/3IrSpXX

PS - Here is a good resource on acceptable voltage ranges:

https://voltage-disturbance.com/voltage-quality/voltage-tolerance-standard-ansi-c84-1/