Planning to install 220 electrical outlet

120 and 240 have been the standard as long as I can recall, and I'm old. However, my circa early-60s GE iron is marked for 115v.
Some UL standards require appliances to pass tests at 120v±10%, that is 108, 120 and 132v. Actual voltage of nominal 120v outlets where I live stays near 124v, so I'd assume the nominal 240 ones are running around 248v.

 

My own theory is that the root of the 220/240 error is linguistic, occurring in the absence of knowledge that two 120v legs can be used to make 240v.

"Is one twenty enough?"

"no, need two."

...and then the word mnemonic gets learned before the physics, gets the better parking spot and sticks around.

 

Edison in the late 1800s started with 110v dc distribution.

Tesla and Westinghouse offered 110v ac rms 60 hz in competition because it was easier to transform and send longer distances. It could also run Tesla's and others ac induction motors. RMS is the average power of the sine wave, in this case 110v.

Some island countries like Cuba and Taiwan still use 110 vac but the US gradually increased to 120 vac by the 1930s.

In reality many parts of the country are now higher than 120 vac rms. I get 125 vac routinely or 250vac across both legs of the center tap utility transformer. It will dip slightly on extreme systemwide loads.

When a large psc residential ac or heat pump starts it will often drop the observed ac voltage by ten to fifteen volts. Appliances and equipment need to stay running and avoid damage. High voltage spikes from nearby lightning strikes are the most damaging, often from instantaneous rises of the ground voltage.

 

I'm more curious about when the actual standard became 120 / 240 nominal (which it has been throughout my career, and still is). Naturally, actual measured voltages can deviate up or down ... 115 and 125 are both within ±5%, as is 250 with respect to 240.

About a dozen years ago, I had occasion to go the university library repository here and have them dig out National Electrical Code editions for me going back to 1920 or so. But I was looking up something else that time, not the voltage spec.

 

The largest factor is… How far is your Electrical panel from where you will have the sun panel for your car charger? If it is short I would run 6G and 240 for future anything. I just did this exact thing for my hot tub. The run was far.. 87’ to the subpanel then 24’ to the actual Hot tub connection. It was very expensive for that much wire. But I did the work myself including pulling the permit, documenting it with photos for pre approval. Installing self closing and self latching gates. I saved $2,987.00 by doing it myself. However I have a lot of experience and have done this about 6 times in my life. If your electrical panel is in your garage already it will be a lot less cost in materials and labor. Shorter run is less materials less time. Get a few electrical quotes. Ask neighbors for recommended electricians. Enjoy your Prime. Don’t forget to run the ICE engine and the AC for 15 mins each month. Even in the winter. To lube the AC components. A park the Prime inside and get a Hyloft system to put your stuff OVER your Car. Or a Shed if you are allowed.

 

220 * 30 = 6.6
240 * 30 = 7.2

Remember that the next time someone asks why specifications state "6.6 kW" as the maximum charging speed and wants to know why reports from owners says it delivers "7.2 kW".

 

According to what I've read, it was 1967 when 120V became standard. It was a gradual increase over the decades from the original 110V, which Tesla and Westinghouse settled on to match Edison's 110V DC system in voltage.

At my house, though, I consistently measure 123 VAC and 245 or 247 VAC depending on which power meter I believe. (I have one on my 6-30 outlet another on my 14-50 outlet.

Interesting side note: I read that the hotel in NYC where Tesla died in 1943 had a large DC generator that operated until the 1960s.

Here's one reference:
https://electronics360.globalspec.com/article/10511/how-the-u-s-came-to-adapt-120v-while-others-are-using-230v

 

NYC still has some weird old electrical stuff. The rotary converters used by the subway system are really something else.

Many older buildings have elevators actuated by very large DC permanent magnet motors. They make the DC on demand with generators driven by modern AC motors.

 

That's earlier than the oldest edition of the N.E.C. that I actually have on my shelf, which is 1990.

Yeah, in the 1990 edition the definition of Voltage, Nominal in Article 100-A says "A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class (as 120/240, 480Y/277, 600, etc.). The actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment."

And in that same edition, in Article 220 "branch-circuit and feeder calculations", section 2 "Voltages" says "Unless other voltages are specified, for purposes of computing branch-circuit and feeder loads, nominal system voltages of 120, 120/240, 208Y/120, 240, 480Y/277, 480, and 600 volts shall be used."

Section numbering sometimes bounces around between editions but the basic information seems to stick around.

The library here has older N.E.C. editions than I have; I think I checked out a few back to 1920-ish once. Maybe I'll go do that again for a few from before and after 1967.

The voltage drops within a building are supposed to be kept less than 5%, by sizing feeders to drop no more than 3%, and branch circuits also no more than 3%, with the combined feeder and branch loss to the farthest outlet to be no more than 5%. In the 1990 edition, that appears in both Article 210 "branch circuits" and Article 215 "feeders" but only as a fine-print note in both places, so it was encouraged, but you wouldn't be dinged over it.

The utility also has some leeway in the range of voltage around "nominal" they can deliver to you, but that might not be in the scope of the N.E.C. but in some other standard covering distribution systems. The N.E.C.'s "voltage, nominal" definition has a fine-print note mentioning an ANSI standard C84.1 "Voltage Ranges for Electric Power Systems and Equipment (60 Hz)", so that might be where the real action is.

Annnd bingo, allowable ranges! The service voltage your utility is allowed to deliver, and the utilization voltage it's allowed to drop to at the ends of your feeders and branches.



According to this, the first version of C84.1 came out in 1954. Now to see about finding that ....

 

If it's not a long shot I would use #6 THHN it will be alot easier to work with especially if your a rookie. Its more $ but very flexible and way easier on your hands. Its what I would use.

Then the colors of the wires would be 2 Reds and 1 Green.

When I bought my house I am in 22 years ago it had a 100 amp service panel. I replaced the panel with a Square D and also had the main power drop from the pole buried in the ground instead of an aerial drop where it penetrates the roof.
And I installed a new meter can and all its bonds. And a lightning rod at the ac compressor.
Passed inspection on the first visit.

In Clearwater the code is arc detect breakers so have lots of those. And some Ditek surge suppressors in the panel.

I also installed an off air antenna and added some pole height to install a Lightning Master Lightning Disapator. The disapators are a miracle I have not been hit since. The science is strong. At my job they have spent $ thousands on disapators as we were getting killed especially the transmitter. Haven't been hit since.

If you have an issue with getting hit alot by lightning this is the solution. Not cheap but they work really well.

Its a must if you live around here lol.

Lightning Protection | Lightning Protection Services | Surge Protection

 

Our utility worked us over pretty good one evening about 25 years ago. I was supervisor of our factory's electricians. I got a call in the middle of the night from a production supervisor that our electrician on shift that night was running out of fuses. The voltage had gone up from the usual 480 to (iirc) about 540V. They had called the utility and the utility said there was nothing wrong on their end.

I rushed over to the plant and verified the crazy voltage. We were such a big customer that they had someone assigned as our liaison and I called him directly and told him what was happening. He said he'd check on it. About a half hour later the power was normal again. He called me the next day to tell me that the tap on the transformer that fed our area had stuck. So, as the power demand went down due to people using less stuff, the voltage went up. That tap is supposed to move and keep the secondary constant. I wonder what it was doing to the homes and small businesses in the area.

 

Yikes ... put on the "120-V Base" scale of the chart, that'd be 135, so well above even Range B.

The house we moved to when I was 11 was in a kind of rural-becoming-exurban area where I don't think the distribution hardware was the latest and greatest.

There would be times when the house would make humming noises—audible, 60 Hz humming noises—overnight, and we'd wake up to fixtures with burned-out light bulbs.

Oh to have a time machine to go back there with a data-logging voltmeter.

 

A few years back I was working late at a temp jobsite supported by gensets. A co-worker asked me why the desk lamp was "doing that" and I saw it was getting dimmer and brighter at maybe an 8 second period.

I ran over to the TV truck and looked at the input meters on the side and saw about a 50 volt variation, and I could hear the onboard voltage regulator slewing the tap from limit to limit in response. Sounded like it was going to saw its way out of the frame!

I called the site electrician and he didn't believe me until I sent him a picture of the gauge.

It turned out that the two paralleled diesel generators had lost sync with each other and were beating on the line. Fortunately he was able to correct it before anything expensive zorched out.

 

I have been in a similar situation. Was it a Filmwerks Genny? NEP Trucks SS24 A.B, and C?

 

If I remember right it was one of the companies FW acquired- that was a while ago.

I can't remember which truck it was for that incident, but I have worked on SS24 occasionally. I don't recall it having a C? though I know they've sent it with one of those support trucks lately, maybe it got a new name.

 

Gotach. Small world. I think I was there. Might have been Palm Springs CA, Golf.of last year.

 

Oh the power incident I remember was Detroit for sure... and I think it was around 2013. But yeah.... mobile tv can be a tiny world.

 

I would agree you will be much happier with a level 2 charger as compared to a level 1 charger. On our PHEV it takes at least 8 hours to fully charge on 120 volts but it will get a full charge with a level 2 240 v charger in about 2 1/2 hours.

If you use your PHEV a lot this will make it much more versatile.

Here is an example - I used to drive one of our kids to their school - it was about a 30 mile trip we did each morning. I plugged back in as soon as we got home and after every errand. In the afternoon I would again make the 30 mile round trip to pick the kid up and plug in as soon as we got home.

It was not unusual for us to drive the PHEV with an estimated 26 electric miles range on a full charge over 90 miles on all electric each day. This makes a big deal when there is a gas shortage or gas that is very high in price.

A level 2 charger would allow you to maximize your ability to drive on electric and recharge your vehicle in a couple of hours when you return home to then get another 30 miles all electric driving out of it. You could do this 2,3 or more times every day.

 

Hey Jerry have you seen this horseshit from Duke Energy about tankless water heaters? Its making the rounds in Network Digest .
Apparently tankless's pull more wasteful power than regular element water heaters and if they make your lights flicker you may need to spend alot of $$$. You may need to replace the pole transformer lol.

That would be quite a surprise to me as I have 2 tankless units and my electric bill is lower lol.

What horrible nonsense. Duke Energy is the the most corrupt the hosing Florida customers got over the Crystal River plant still pisses me off.

Tankless Water Heaters - Duke Energy

 

Two things can be true at the same time, like the storage unit using a little energy a lot of the time, and the tankless one using less total energy for the month, but in giant big slurps when it runs.

I once (briefly) thought about swapping the gas storage heater here for gas tankless, until I realized I'd need to increase the diameter of the gas supply piping and change the vent piping for large diameter $tainle$$ $teel, again so it could use less energy overall but in a frightful big whoosh when it runs.

Both the overall usage and the when-running draw need to be provided for.