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My 30 A dryer outlet reads 122 and 123 V on my multimeter (a total of 245 V). Will this be a problem for a new modern dryer if it is higher than 240 V?

It is a three prong outlet.

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  • Every time someone turns on an electrical device, it draws current. When it draws current, the grid voltage drops. If someone turns off an electrical device the current draw stops - the grid voltage rises. During the day, millions of people are turning things on an off. During the day the grid voltage goes up and down. If it gets too high, grid operators turn off generating plants to bring the voltage back down. If it gets too low, they activate generating plants to bring the voltage back up. This is why voltage floats within a range. – J... Feb 8 at 13:59
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That is well within ANSI C84.1 North American Utlity Standards.

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    For OP: The important column is "Utilization", which are the allowed voltages at the outlet. – BlueRaja - Danny Pflughoeft Feb 3 at 20:54
  • @BlueRaja-DannyPflughoeft Citation? I would have assumed the NEMA numbers would be authoritative and applicable (granted, the posted chart doesn't define exactly what "Service" / "Utilization" / "Nameplate" mean...). – Dai Feb 5 at 8:39
  • @Dai ANSI C84.1 mentioned in the answer. I believe "NEMA" refers to what the equipment needs to be certified for. Not sure about "nameplate" - maybe what goes on the label? – BlueRaja - Danny Pflughoeft Feb 5 at 10:43
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240 V is the "nominal" reading. You'll usually get ±10% voltage from the utility lines, and your appliances are designed to accommodate that variation.

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You will be fine with that. The power company usually delivers 5% +or - the normal 120/240 residential voltage. Your meter also has a tolerance of up to 3%.

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    @GeorgeAnderson My dryer's been three prong since I moved in in 1982. New townhouse and they ran 10/3 w GND but used three prong receptacle... I never changed it. OMG, hope Harper doesn't read this. – JACK Feb 3 at 14:57
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    Because when you moved in, I bet your builder asked you whether your dryer was 3-prong or 4-prong @JACK. (3-prong was legal in 1982). Since changing the wall socket is in the builder's bailiwick and changing the dryer cord is not. Now, everytime you get a dryer, the appliance store changes the cord, because changing the cord is in their bailiwick and changing the socket is not. It's a frickin' virus. If nothing is done, all dryer sockets will be 3-prong by 2050! :) – Harper - Reinstate Monica Feb 3 at 17:45
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    Meanwhile in the rest of the world, everything is 240v, and we don't centre tap it. 3 conductors, live, neutral, ground. – Phil Feb 3 at 21:32
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    @Phil I believe it's actually 230V in the rest of the world. Which is interchangeable with 240V for most practical purposes – user253751 Feb 3 at 21:36
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    230 is a myth, in practice it's actually either 240 or 220 depending on where you are. – Jasen Feb 4 at 5:36

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