US power system

[Uncle Peter]

Found the 2 below quotes by mistake when googling, relevant parts asterisked. How on earth does connecting a 240 V load make the missing neutral problem go away for the 120 V appliances?

I can answer this with experience. A long long time ago, (about 1987) we experience some weird happenings with our lights and whole house fan. The whole house fan is what tipped us off to the problem initially. It all of a sudden just slowed down. Some lights were bright, some were dim. The TV would not come on. After poking around a bit, i got out the (analog) meter and found some outlets had about 80 volts and others had about 144. ******Then, some how, i had the brilliant idea of turning on the oven. When i turned the oven on, the fan went back to normal, the lights normal. The 240v load apparently balanced the system.****** I was at somewhat of a loss at that point. I was not near as experience in electrical things at that time. I called an electrician friend of mine, he came down, poked around in the box some and decided to loosen the ground on the buss. "OH! GUESS WHAT? Fire on the ground" he said. I'm like "what's that mean"?. He said "well even though i've never seen this before, it sure looks like an open neutral. So i get on the horn with the power company. FYI, it was Kansas City Power and Light. They come out, and basically look at what i'm experiencing and the first thing the guy does is pull the meter. Then he measures the voltages on the incoming legs. All is equal. Then he tells me the problem must be on the inside. Puts the meter back in and the imbalance returns. "yep , he says, problem is on your side". So at this point, i'm at wits end, not knowing what to do, so I calls the fire dept and they say 'do you have a fire'? I says no, but I will, if someone does not fix this power imbalance. So that prompts a little higher level of action from KCPL, and they come out again. The service guy makes all his checks and then talks on the radio for a while. His supervisor says "you know that sounds like an open neutral". The guy comes back and says they suspect an open neutral. At that point, I explode. I said "NO SHIT SHERLOCK" I told you guys that 3 hours ago. They ran a bare wire from my meter can to the service box on the street and lo and behold, all becomes normal again. (did i mention i have underground service?) They came out the next day and started digging. About a foot from my water meter, at a depth of about 16" the neutral wire was corroded clean in half. Apparently it had been nicked by the backhoe putting in the water line 10 year prior. Well anyway, they fixed the wire, and all was good for exactly a year to the day. It was so weird, one year later, HALF the stuff in the house quit working. I had a dead leg. When they came out, i explained what had happened the year before and so they dug again. Sure enough, about 2 feet from the neutral problem, one of the hot legs had corroded in half.

After screwing around with it, I decided the drill was > dying and went to get another one from the back room. That room is > dark so I flipped on the lights. They were real dim. That's when I > realized there might be an electrical problem. I took that drill to > the house and it worked fine. I went back to the garage and plugged > it into another outlet. As soon as I turned it on, those dim lights > in the back room got real bright, and a few seconds later they went > out (they were CFL bulbs). thats when something smelled hot, and I > found smoke around one of those CFL bulbs. I shot off the switch to > those lights and got my test meter. I got odd votages all over the > garage. I flipped on a light on another breaker and it flashed and > burned out immediately. At that same time the radio in there which > always comes on when I turn on the lights, got real loud, then quit. ******I flipped on my 240V welder and it worked fine. At the same time I > noticed the outdoor flood light came on. With the welder on, I > flipped on soem more lights and they all worked normally. When I shut > off the welder some lights got real dim, others real bright.******

[Uncle Peter]

Plus.... I've found a few websites saying 220V American appliances can't operate in the UK, because they have two phase power over there? WTF? Surely all their big appliances see is 220V, connected from L1 to L2. Over here they get the same, but L to N.

[Dave Liquorice]

They might object to our nominal 230 V, commonly 240 V and allowed maximum of 253 V... 220 V is just 4 V above our allowed minimum.

[Davey]

[Martin Brown]

It can be true of US inductive loads like motors built down to a price. The difference in current between a 60Hz design and 50Hz operation can be a nearly 20% increase in current draw. Running hot = shorter life.

A lot of stuff sold in the USA comes with a US only wallwart PSU. Japanese kit comes with the ability to run on either since half the country has US installed 60Hz generators and the rest British 50Hz.

[Tim Watts]

Also, as their supply for 220V is actually 110-0-110 the appliance might not have insulation factory tested for 220V to earth.

I say tested as it's pretty unlikely they used wires that were good for

110V but not 220V - it's just it may not have been type tested for that scenario so they don't want to say you can...

[Gazz]

Japan uses 100 volts mind,

America, the houses have 2 phases at 110 volts coming in, the breaker box is split in half, and half the house wired on one 110 volt phase, the other half wired to the 2nd phase, they need to balance the loads a bit to avoid overloading the common neutral.

When they put in a 220 volt appliance (tumble drier, cooker/range, big welder, RV power, big air conditioners etc) they use both 110 volt phases and not the neutral wire, if the neutral is used it will be for 110 volt parts in the appliance... the motor in the tumble drier, clock on the cooker etc.

[snot]

Oven I bought just recently could be wired to a 2 phase system. I did wonder why - so it's the American way of getting enough current to operate appliances. Ah! Snot

[Tim Watts]

I presume they use a double pole MCB too?

Does this mean that their back end supply is actually 6 phase?

[Brian Gaff]

Are you still on the medication though. Sounds like you needed a live in electrician with a jcb. Brian

[philipuk]

No.

American houses are typically supplied split phase, where a single phase is centre grounded, giving two legs each at approx 120v to earth each and 240 v between each other. Some do have two phases of a three phase supply givin g 208v between each other (this causes problems). This is the situation at least domestically.

They also have another strange layout called high leg delta, where power is three phase delta connected, with one of the phases centre grounded, givin g two legs with 120V to neutral, 240v phase to phase and one phase with 208 v to neutral.

The back end is normal three phase power.

Philip

[Uncle Peter]

Eh?

[Uncle Peter]

That's the bit where I'm confused. I have seen a few blogs from Americans that lost their neutral, which obviously caused some lights to be too bright and others too dim. But what doesn't make sense is when they turned on the cooker, it stabilised it. That would only make sense if the cooker had a neutral connection strapped to the middle of the heating element. Why would they do that?

Also it sounds like quite a few houses have caught fire over there with a lost neutral, due to 110 volt appliances getting 220V and catching fire. What amused me though is the Americans who had bright and dim lights for ages, and never thought to test the voltages with a meter, and even worse, the guy from the electricity board didn't notice either!

[Uncle Peter]

Here's one:

"Can I connect an American 220 Volt Dryer or other 220 volt American products to a Transformer? No you cannot connect an American 220 Volt Dryer or other 220 volt american products to a Transformer. Voltage Transformers are made to convert single phase 110 or 220 volt. American 220 volt consists of 2 phase of 110 volt and European 220 volt consists of 1 phase of 220 volt."

[Uncle Peter]

But 2 phase looks just like 1 phase to the appliance.

[Uncle Peter]

Safety conscious idiots needing heavier wire everywhere.

[Tim Watts]

Gawd - what a mess.. Sounds like the ancient days in London when you had funky weird local supplies like one voltage for lighting, another for power hungry devices and some random 90-degree 2 phase supplies.

My father worked on some of the old equipment that was used to integrate that lot - including Scott and Leblanc transformers that can interface 3 phase with 2-phase/90 degree systems.

Of course, they managed to eventually get rid of all the crap.

[Uncle Peter]

I'm taking about the transformers in substations.

What's wrong with the wavelength?

Yes, and our time system is awful. Why base electricity on something already non-metric?

[Dave Plowman (News)]

Must have been made for 60 Hz...

[Brian Gaff]

Well, have you actually read your post? It sounded a bit like a rant, andhence my comment. Brian