Harmonizing the 2nd lowest American utilization voltage.. 208 and 240v

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Besoeker

Senior Member
Location
UK
It is just one aspect of discussion which shows even with different voltages a US home can be safer than a EU home in certain circumstances.
Do you think 120-0-120V is safer than 230V?

May be so in developed countries. But in developing countries more usage of 3 phase supply.
I don't know about the practices for residential supplies in developing countries. Your post infers that you do and that's fine.
But I would have thought that residences in developing countries have fewer electrical appliances and thus a lower load demand. That seems at odds with the requirement for a three phase supply.

Nor does an appliance in a US home.
My point was about the very low probability of a 400V electrocution in a residence.

The article originated in India and in the Abstract it talks about more fatalities due to electrocution here compared to Bulgaria and Canada and 230V single phase supply is used here.
Good. You read it.
Given that Bulgaria is in the EU it rather negates your point in post #6:

It is not substantiated in the article that fatal accidental electrocutions are lesser in countries in the EU using 230V
 

Besoeker

Senior Member
Location
UK
The American automotive industry is a good example. They have gone a long way toward making cars metric.
I agree.
With a world market, I think that was inevitable. Like UK, USA and other countries, have manufacturing plants for foreign makes. Toyota, for example, have plants all over the world.
Since most nations use metric (SI) it really wouldn't make sense to use non-standard parts for the US market.
Tyres (tires) are an interesting exception....

I imagine we don't export much pipe and wire though. I have never encountered metric-sized conduits and conductors.
We don't often use conduit here but, when we do, the dimensions are in mm as a rule.
That said, older properties have plumbing in Imperial units but the metric sizes are just about close enough to make compression joints work.

I'll bet they don't even use British Thermal Units in Britain anymore.
You'd win that bet if anyone took you on............:)

I'm just glad volts and amps are already meteric.
I don't think they were ever anything else.
 

kwired

Electron manager
Location
NE Nebraska
Let's crawl into dreamland for a moment. We're all going to go to bed tonight and wake up tomorrow with the best electrical generation and distribution system and everyone gets free electrical appliances, devices, etc., all compliments of the tooth fairy. All we have to do is make up our mind, and agree, on what we want.

We're right back to the original debate. AC or DC? (The last DC grid in NYC was shut down in 2007 from what I understand). How many volts per phase? How many phases? What frequency? What kind of power? Is it fossil, nuclear, wind, wave, etc.?

Ask that many questions and you'll end up with more complicated systems than you have now.

What we have works. It's not that tough to manufacture something that works worldwide. Some modifications here and there, but overall, what we have works quite well.

One day when we have no grid you'll be able to produce onsite whatever power you want.

Until then, we have what we have and we know how to utilize it to meet our needs.

Another reason AC was chosen for distribution is it is simpler to transform to other voltages than DC.
 

glene77is

Senior Member
Location
Memphis, TN

Good coverage on this subject.
Now, from another perspective, What Happens if you install a Single-Phase 240V motor on a 3phase 208V system ?
Surely this is an incompatibility example.

Will it Chug-Chug-Thud ?

glene77is
 

kwired

Electron manager
Location
NE Nebraska
Good coverage on this subject.
Now, from another perspective, What Happens if you install a Single-Phase 240V motor on a 3phase 208V system ?
Surely this is an incompatibility example.

Will it Chug-Chug-Thud ?

glene77is

depends, if you only connect it to two phase conductors, it simply draws roughly 10% more current at rated load. If you are determined to somehow connect all three phases to the motor.... smoke is probably released from something:happyyes:
 

glene77is

Senior Member
Location
Memphis, TN
depends, if you only connect it to two phase conductors, it simply draws roughly 10% more current at rated load. If you are determined to somehow connect all three phases to the motor.... smoke is probably released from something:happyyes:

KWired,
Thank you. Your 3phase humor scares me.
Was imagining Just a two wire and neutral connection,
as another example of incompatibilities.
 

Sahib

Senior Member
Location
India
Do you think 120-0-120V is safer than 230V?
Yes, because the probability of touching both live conductors to get 240V shock in 120-0-120V single phase supply is much lower than the probability of touching a single live wire to get 230V shock in a 230V single phase supply.
I don't know about the practices for residential supplies in developing countries. Your post infers that you do and that's fine.
But I would have thought that residences in developing countries have fewer electrical appliances and thus a lower load demand. That seems at odds with the requirement for a three phase supply.
There are many affluent and middle class families in developing countries and they want three phase supply because if in one phase the power is not available or low voltage , the other phase with power or good voltage will be availed by using a rotary change over switch.
My point was about the very low probability of a 400V electrocution in a residence.
Low probability does not equate to impossibility.
Good. You read it.
Given that Bulgaria is in the EU it rather negates your point in post #6:
Thanks for information.
 
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kwired

Electron manager
Location
NE Nebraska
Yes, because the probability of touching both live conductors to get 240V shock in 120-0-120V single phase supply is much lower than the probability of touching a single live wire to get 230V shock in a 230V single phase supply.
Just FYI - there is likely more electrocutions in the US involving 120 volts than any other voltage - take that however you want to, bottom line is more people are exposed to 120 volts to ground most often and many have a tendency to disrespect it also, after all it is only "one-ten" and I have been shocked by that before is the mentality taken by many

There are many affluent and middle class families in developing countries and they want three phase supply because if in one phase the power is not available or low voltage , the other phase with power or good voltage will be availed by using a rotary change over switch.
What/where is this switch? Sounds like something that would be on the utility side to me. If I were to supply a dwelling with three phase and a phase was lost: 1. yes we will not have total loss of power. 2. by design the load will be somewhat balanced, so by transferring like you mention you throw that balance off - maybe overloading something 3. it would be possible just because three phase is there that HVAC or other heavy loads need all three phases or they don't work anyway.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
It should be done, the current set up I think is stupid and stuck in the past. Converting to 240 with domestic appliances would be a piece of cake for most manufacturers in that many already make 230 volt equipment overseas. Having a global voltage of 230-240 cuts stock in half.

Changing over residential would not be to hard. We already have 240, all that would be needed are 240 volt plugs and swapping to double pole breakers. Wiring wouldn't need to changed at all, the conversion can literally be done in hours. 240 gives more KW per circuit and less copper in new construction.

If houses stayed at straight 240 it will solve a mountain of problems. The fire hazards associated with open neutrals will be eradicated, stray current on ground rods and water bonds will disappear. Neutral to ground faults going unnoticed will not exist. 3 wire sub panels and neutral/ground jumping seen literally in every other install will not be of issue. Greatly simplified wiring and no more confusion. Plus 10-2 for dryers and 6-2 for ranges:D 120 volts to ground will keep things safe as they are now.

Some would argue though having a side grounded leg at 240 would be better than a center grounded winding solely because double pole light switches would need to be used and the incandescent screw base socket would become dangerous. But as is GU24 sockets are being phased in and light switches shouldn't be used as service disconnects anyways. So 2 live legs should be a non issue.


Houses and light commercial have 5 options in the long run. 120-0-120 used as straight 240 (which will be our starting point since its already here), 0-240 which should be avoided for many reasons, 138/240Y with houses having the option of going 3 phase which in theory would increase efficiency and allow the use of 3 phase 240 AC and the final option would be 240/415Y, with houses either only getting 240 single phase or 240/415 3 phase. Utilities will love the 415 voltage in that it can travel farther meaning fewer transformers per neighborhood. 415 in houses will mean 12-3 for ranges, European ranges are 3 phase configurable as is.


Commercial will go 240/415Y. 415 is close to 480 which would mean only a slight increase in conductor size, but that almost always would be offset where 120 equipment now exists because there is no need for expensive and inefficient 480 to 120/208 step down transformers. Heavy, expensive, confusing and yup, even when no power is being drawn from the secondary the meter is still spinning with the primary pulling 140 plus watts for a 25kva unit, and of course higher with the kva. Intelli-volt fluorescent ballasts and LED drivers wont care for 277 going to 240. And fun fact, where 400 watt HPS lamps exist such as parking lot lighting and highways a simple reactor ballast can be used, just like with 150 watt and lower HPS lamps at 120 volts.

There is one irony here though, standardizing at 240 would phase out 208 with more ease, however because 277/480 is so close to 415, we will end up with dual rated 415-480 volt equipment, exactly equivalent percentage wise to our 208-240. Of course we could phase out 480, but who knows:roll:


Something else I would like to see, the NEC raising the 600 volt limit to 1000volts. I dont see 400 extra volts being an issue, but 415/718Y and a 577/1000Y would be beneficial to large commercial and industrial customers.

Also of thought would be to harmonize with the IEC colors, but that probably would never happen here.:roll:
 

Besoeker

Senior Member
Location
UK
Yes, because the probability of touching both live conductors to get 240V shock in 120-0-120V single phase supply is much lower than the probability of touching a single live wire to get 230V shock in a 230V single phase supply.
To earth, possibly. For a 240V appliance the risk still exists.

There are many affluent and middle class families in developing countries and they want three phase supply because if in one phase the power is not available or low voltage , the other phase with power or good voltage will be availed by using a rotary change over switch.
So still only one phase in use at any one time?
And I'm sure you have many documented examples from the many affluent and middle class families who have such an arrangement.
Care to cite them?

Low probability does not equate to impossibility. [/agreed]
That's why I couched it terms of very low probability.
Someone could run a 230V extension lead from an area served by one phase to another area served by a different phase and end up with two of the phases, thus 400V in one area.The potential then exists for a a couple different faulty cables or appliances. So, you can't discount the possibility. However remote. That said, I have no recollection of any reference to a fatality resulting from a 400V electrocution in a domestic residence.

I have to site through a lot of mandatory electrical (and other) safety both internally and externally. And I get a lot of business related bulletins on health and safety matters.
One might have expected a residential 400V fatal electrocution to have been flagged up. None that I have seen. Maybe you have.

Thanks for information.
YW.
Sometimes it's a good idea to check facts before making assertions.
 

Besoeker

Senior Member
Location
UK
It should be done, the current set up I think is stupid and stuck in the past. Converting to 240 with domestic appliances would be a piece of cake for most manufacturers in that many already make 230 volt equipment overseas. Having a global voltage of 230-240 cuts stock in half.

Changing over residential would not be to hard. We already have 240, all that would be needed are 240 volt plugs and swapping to double pole breakers. Wiring wouldn't need to changed at all, the conversion can literally be done in hours. 240 gives more KW per circuit and less copper in new construction.

If houses stayed at straight 240 it will solve a mountain of problems. The fire hazards associated with open neutrals will be eradicated, stray current on ground rods and water bonds will disappear. Neutral to ground faults going unnoticed will not exist. 3 wire sub panels and neutral/ground jumping seen literally in every other install will not be of issue. Greatly simplified wiring and no more confusion. Plus 10-2 for dryers and 6-2 for ranges:D 120 volts to ground will keep things safe as they are now.

Some would argue though having a side grounded leg at 240 would be better than a center grounded winding solely because double pole light switches would need to be used and the incandescent screw base socket would become dangerous. But as is GU24 sockets are being phased in and light switches shouldn't be used as service disconnects anyways. So 2 live legs should be a non issue.


Houses and light commercial have 5 options in the long run. 120-0-120 used as straight 240 (which will be our starting point since its already here), 0-240 which should be avoided for many reasons, 138/240Y with houses having the option of going 3 phase which in theory would increase efficiency and allow the use of 3 phase 240 AC and the final option would be 240/415Y, with houses either only getting 240 single phase or 240/415 3 phase. Utilities will love the 415 voltage in that it can travel farther meaning fewer transformers per neighborhood. 415 in houses will mean 12-3 for ranges, European ranges are 3 phase configurable as is.


Commercial will go 240/415Y. 415 is close to 480 which would mean only a slight increase in conductor size, but that almost always would be offset where 120 equipment now exists because there is no need for expensive and inefficient 480 to 120/208 step down transformers. Heavy, expensive, confusing and yup, even when no power is being drawn from the secondary the meter is still spinning with the primary pulling 140 plus watts for a 25kva unit, and of course higher with the kva. Intelli-volt fluorescent ballasts and LED drivers wont care for 277 going to 240. And fun fact, where 400 watt HPS lamps exist such as parking lot lighting and highways a simple reactor ballast can be used, just like with 150 watt and lower HPS lamps at 120 volts.

There is one irony here though, standardizing at 240 would phase out 208 with more ease, however because 277/480 is so close to 415, we will end up with dual rated 415-480 volt equipment, exactly equivalent percentage wise to our 208-240. Of course we could phase out 480, but who knows:roll:


Something else I would like to see, the NEC raising the 600 volt limit to 1000volts. I dont see 400 extra volts being an issue, but 415/718Y and a 577/1000Y would be beneficial to large commercial and industrial customers.

Also of thought would be to harmonize with the IEC colors, but that probably would never happen here.:roll:
Good points, many of which I agree with.
And just a couple I don't.
It's coming up to 23:00 here, I've been up since 04:30, on the road at 05:30 and back home at at 17:30. And a 300 mile round trip.
Second in a week. Plus a 210 mile trip for personal reasons on Monday.
I'm a bit knackered. But maybe tomorrow I'll come back to this.
 
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