Need some help, what is percentage US voltages on 115V, 208V

[Whoey Louie]

On Friday, November 1, 2019 at 2:52:04 PM UTC-4, upsid...@downunder.com wrote:

On Fri, 1 Nov 2019 10:32:49 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Friday, November 1, 2019 at 12:06:22 PM UTC-4, Whoey Louie wrote:
On Friday, November 1, 2019 at 11:32:00 AM UTC-4, Rick C wrote:
On Friday, November 1, 2019 at 11:06:29 AM UTC-4, Whoey Louie wrote:

If we were to start from scratch, I see
compelling advantages to going with 240V as the standard for all
loads, eg an electric kettle could heat twice as fast. I see
some small advantages, eg the 50 cents above, but I sure
don't see a compelling advantage to 3 phase for homes.

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.

IDK what they do over there. But yes, I was assuming that we'd
continue to use the same size minimum conductors, so a 15A
circuit would then deliver twice the power.




If we weren't going to save on the cost of wiring there is no real reason to convert.

Who said anything about converting? I said if we were starting from
scratch.

Either way. No point if it doesn't save money. That is the point of 3 phase. While it makes many things more complex, it saves on copper costs.

One significant advantage is that you easily get a rotating field, so
a 3 phase motor is simple, no need for special arrangements to get the
motor started. Before VFDs became common, this was an important issue.

One significant problem especially in the US is the low voltages
(120/240 V) and hence large currents. This means that the distribution
transformer (pole pig) must be very close to the load, which requires
a dense medium voltage (14 kV?) network.

The low voltages can be blamed on Edison and his incandesce lamps that
initially had a low voltage rating. Later versions could handle
voltages over 200 V, so the rest of the world adapted 220-240 V for
lamp loads.

Lets speculate what the distribution would look today, if designed
from scratch.

Now that the incandesce lamps are gone, a much higher voltage could
be selected.

These days a 750 to 1500 Vdc distribution voltage could be selected.
If 3 phase is needed for some motors, a VFD from +/-350 Vdc could be
used to generate 230/400 V with low distortion. With a DC feed no need
for a PFC. For small loads simple DC/DC converters could be used.
These would be simpler than current inverters, since there would be no
need to generate a sine voltage.

You're advocating 750 to 1500 volts going into homes, small
businesses, etc?

 

[Whoey Louie]

On Friday, November 1, 2019 at 12:34:52 PM UTC-4, keith wright wrote:

On Friday, 1 November 2019 08:32:00 UTC-7, Rick C wrote:
...

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.
...

Strictly speaking the circuits are usually 30Amp (wired as a ring main) with a local fuse inside the plug that depends upon the load. It can be up to 13A.

kw

So, instead of conductors being smaller than what is typically used in the US
where we have 15a or 20a, the conductors are actually larger. Higher
voltage and higher current. Thanks for clearing that up.

 

[Jasen Betts]

On 2019-10-31, Steve Wilson <no@spam.com> wrote:

Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

he's Canadian but, https://youtu.be/kfHB5AoAAbs

Bad design.

1. Use a stepdown transformer to drive the 120V dust collector.

2. Use a DPDT switch to turn table on and off. This eliminates the 9V battery
and the power lost in the semiconductor switch. Simpler, no need for a heat
sink.

he already has a SPDT switch, he's need SP3T

3. use a current relay to switch the 120V

4. use a 240V dust collector

--
When I tried casting out nines I made a hash of it.

 

On Fri, 1 Nov 2019 17:16:33 -0700 (PDT), Whoey Louie
<trader4@optonline.net> wrote:

On Friday, November 1, 2019 at 2:52:04 PM UTC-4, upsid...@downunder.com wrote:
On Fri, 1 Nov 2019 10:32:49 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:

On Friday, November 1, 2019 at 12:06:22 PM UTC-4, Whoey Louie wrote:
On Friday, November 1, 2019 at 11:32:00 AM UTC-4, Rick C wrote:
On Friday, November 1, 2019 at 11:06:29 AM UTC-4, Whoey Louie wrote:

If we were to start from scratch, I see
compelling advantages to going with 240V as the standard for all
loads, eg an electric kettle could heat twice as fast. I see
some small advantages, eg the 50 cents above, but I sure
don't see a compelling advantage to 3 phase for homes.

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.

IDK what they do over there. But yes, I was assuming that we'd
continue to use the same size minimum conductors, so a 15A
circuit would then deliver twice the power.




If we weren't going to save on the cost of wiring there is no real reason to convert.

Who said anything about converting? I said if we were starting from
scratch.

Either way. No point if it doesn't save money. That is the point of 3 phase. While it makes many things more complex, it saves on copper costs.

One significant advantage is that you easily get a rotating field, so
a 3 phase motor is simple, no need for special arrangements to get the
motor started. Before VFDs became common, this was an important issue.

One significant problem especially in the US is the low voltages
(120/240 V) and hence large currents. This means that the distribution
transformer (pole pig) must be very close to the load, which requires
a dense medium voltage (14 kV?) network.

The low voltages can be blamed on Edison and his incandesce lamps that
initially had a low voltage rating. Later versions could handle
voltages over 200 V, so the rest of the world adapted 220-240 V for
lamp loads.

Lets speculate what the distribution would look today, if designed
from scratch.

Now that the incandesce lamps are gone, a much higher voltage could
be selected.

These days a 750 to 1500 Vdc distribution voltage could be selected.
If 3 phase is needed for some motors, a VFD from +/-350 Vdc could be
used to generate 230/400 V with low distortion. With a DC feed no need
for a PFC. For small loads simple DC/DC converters could be used.
These would be simpler than current inverters, since there would be no
need to generate a sine voltage.

You're advocating 750 to 1500 volts going into homes, small
businesses, etc?

Why not ?

Much of the electric hardware is certified for the whole Low Voltage
Directive (LVD, max 1000 Vac, 1500 Vdc) range. The wiring practices
would not need radical changes.

The problem would be some of the Far-East import, which is not
compatible even wish 230 Vac (creepage distances etc.

 

On Fri, 1 Nov 2019 17:19:12 -0700 (PDT), Whoey Louie
<trader4@optonline.net> wrote:

On Friday, November 1, 2019 at 12:34:52 PM UTC-4, keith wright wrote:
On Friday, 1 November 2019 08:32:00 UTC-7, Rick C wrote:
...

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.
...

Strictly speaking the circuits are usually 30Amp (wired as a ring main) with a local fuse inside the plug that depends upon the load. It can be up to 13A.

kw

So, instead of conductors being smaller than what is typically used in the US
where we have 15a or 20a, the conductors are actually larger. Higher
voltage and higher current. Thanks for clearing that up.

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.

 

On Saturday, 2 November 2019 07:48:09 UTC, upsid...@downunder.com wrote:

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.

No. There is only one fuse or circuit breaker for the whole ring.
The two ends of the ring final circuit are joined together at the single
circuit breaker. Having two as you described is explicitly prohibited.

John

 

[Whoey Louie]

On Saturday, November 2, 2019 at 9:01:03 AM UTC-4, jrwal...@gmail.com wrote:

On Saturday, 2 November 2019 07:48:09 UTC, upsid...@downunder.com wrote:

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.

No. There is only one fuse or circuit breaker for the whole ring.
The two ends of the ring final circuit are joined together at the single
circuit breaker. Having two as you described is explicitly prohibited.

John

That makes sense. If there were two, both would blow at about the same
time due to over current anyway. One would go, the current in the second
would double, and then it would blow too.

 

[Whoey Louie]

On Saturday, November 2, 2019 at 3:48:09 AM UTC-4, upsid...@downunder.com wrote:

On Fri, 1 Nov 2019 17:19:12 -0700 (PDT), Whoey Louie
trader4@optonline.net> wrote:

On Friday, November 1, 2019 at 12:34:52 PM UTC-4, keith wright wrote:
On Friday, 1 November 2019 08:32:00 UTC-7, Rick C wrote:
...

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.
...

Strictly speaking the circuits are usually 30Amp (wired as a ring main) with a local fuse inside the plug that depends upon the load. It can be up to 13A.

kw

So, instead of conductors being smaller than what is typically used in the US
where we have 15a or 20a, the conductors are actually larger. Higher
voltage and higher current. Thanks for clearing that up.

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Must be fun when the one breaker trips and everything in the house goes
off, including all the lights.

Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.

I would expect that both fuses must blow at the same time. With a ring,
the current would be about evenly split between the two sources. As
soon as one fuse blows, the current in the other fuse would double and
it will blow. Are you still really using fuses, not breakers? Here
for new work, circuits for living space have to be on AFCI breakers now
too, for arc fault protection.

 

[Tom Gardner]

On 02/11/19 13:51, Whoey Louie wrote:

On Saturday, November 2, 2019 at 3:48:09 AM UTC-4, upsid...@downunder.com wrote:
On Fri, 1 Nov 2019 17:19:12 -0700 (PDT), Whoey Louie
trader4@optonline.net> wrote:

On Friday, November 1, 2019 at 12:34:52 PM UTC-4, keith wright wrote:
On Friday, 1 November 2019 08:32:00 UTC-7, Rick C wrote:
...

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.
...

Strictly speaking the circuits are usually 30Amp (wired as a ring main) with a local fuse inside the plug that depends upon the load. It can be up to 13A.

kw

So, instead of conductors being smaller than what is typically used in the US
where we have 15a or 20a, the conductors are actually larger. Higher
voltage and higher current. Thanks for clearing that up.

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Must be fun when the one breaker trips and everything in the house goes
off, including all the lights.

Except of course it doesn't.

Traditionally each floor in a suburban house has one ring main
for the sockets and another for the lights. High current devices
have a dedicated spur from the distribution point.

Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.


I would expect that both fuses must blow at the same time. With a ring,
the current would be about evenly split between the two sources. As
soon as one fuse blows, the current in the other fuse would double and
it will blow.

Except the presumption is wrong.

Are you still really using fuses, not breakers? Here
for new work, circuits for living space have to be on AFCI breakers now
too, for arc fault protection.

Depends on the age of the installation.

Never heard of AFCI breakers, but that's my ignorance.

 

[Joerg]

On 2019-10-31 17:10, Rick C wrote:

On Thursday, October 31, 2019 at 7:38:49 PM UTC-4,
klaus.k...@gmail.com wrote:
On Thursday, 31 October 2019 16:27:12 UTC+1, Rick C wrote:
On Thursday, October 31, 2019 at 4:33:20 AM UTC-4,
klaus.k...@gmail.com wrote:
Hi

I am working on a US variant on a small pump (below 75W)

But, I am unable to find the percentage of distribution of
different US mains voltage

My guess is that most is 115V, but I have also heard about 208V
(phase phase), and 240V (120V, 180 degrees phase inverted)

Any inputs of how much is 115V grid, how much 208, how much
240V?

A large percentage of commercial installations are 208 volts
rather than 240. I charge my car at level 2 chargers in lots of
locations and some 90% of them are 208 volts (give or take)
rather than 240. Instead of getting 7 kW charging rate, I
usually see 6 or below because of the voltage.


Good info

Commercial, would that be businesses, hotels, or what?

Pretty much yes. Hotels, hospital parking deck, retail food store,
retirement community parking. These are the ones I recall off the
top of my head. I'm sure I've seen 240 volt level 2 charging, but I
don't recall where that would have been.

Even among those commercial operations most of the small ones will only
have 120/240V wiring, two-phase 180 degrees. 208V three-phase is pricey,
needs a special transformer and is typically only used in larger places
or ones with a high electric energy demand.

Klaus, in the US you will usually see ground distributed to 240V outlets
even though it is often not used by the equipment that is plugged in. So
there are four connections, 120V phase 1, 120V phase 2, neutral,
protective ground. What you need to keep in mind is that such outlets
are generally fused at much more than the usual 15A or 20A. So the cable
from the outlet to the fuse in your pump circuitry must be rated for the
highest expected circuit breaker current rating.

Older homes can have 240V three-prong outlets where you don't have
neutral, for example for dryers and in the kitchen for a free-standing
oven/range. AFAIK that is no longer allowed for new construction in many
states.

Hardwired equipment such as a built-in kitchen oven or range often does
not have neutral either but there you cannot legally connect anything
else without having an electrician run cable and a new outlet.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Whoey Louie]

On Saturday, November 2, 2019 at 10:10:35 AM UTC-4, Tom Gardner wrote:

On 02/11/19 13:51, Whoey Louie wrote:
On Saturday, November 2, 2019 at 3:48:09 AM UTC-4, upsid...@downunder.com wrote:
On Fri, 1 Nov 2019 17:19:12 -0700 (PDT), Whoey Louie
trader4@optonline.net> wrote:

On Friday, November 1, 2019 at 12:34:52 PM UTC-4, keith wright wrote:
On Friday, 1 November 2019 08:32:00 UTC-7, Rick C wrote:
...

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.
...

Strictly speaking the circuits are usually 30Amp (wired as a ring main) with a local fuse inside the plug that depends upon the load. It can be up to 13A.

kw

So, instead of conductors being smaller than what is typically used in the US
where we have 15a or 20a, the conductors are actually larger. Higher
voltage and higher current. Thanks for clearing that up.

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Must be fun when the one breaker trips and everything in the house goes
off, including all the lights.

Except of course it doesn't.

Traditionally each floor in a suburban house has one ring main
for the sockets and another for the lights. High current devices
have a dedicated spur from the distribution point.

I was going by what someone who lives there posted. And even by what
you say, if it's a one floor house, then all the lighting circuits go
out. In the US you'd lose one lighting circuit, not all of them.

Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.


I would expect that both fuses must blow at the same time. With a ring,
the current would be about evenly split between the two sources. As
soon as one fuse blows, the current in the other fuse would double and
it will blow.

Except the presumption is wrong.

Again, I just went by what the other poster claimed, so I guess he's
full of baloney.

Are you still really using fuses, not breakers? Here
for new work, circuits for living space have to be on AFCI breakers now
too, for arc fault protection.

Depends on the age of the installation.

I said for "new work". And that's what the code is, you have to comply
with current code for new work it doesn't depend on the age of what's
already there.

Never heard of AFCI breakers, but that's my ignorance.

Google broken?

 

On Sat, 2 Nov 2019 09:04:08 -0700 (PDT), Whoey Louie
<trader4@optonline.net> wrote:

On Saturday, November 2, 2019 at 10:55:41 AM UTC-4, Joerg wrote:
On 2019-10-31 17:10, Rick C wrote:
On Thursday, October 31, 2019 at 7:38:49 PM UTC-4,
klaus.k...@gmail.com wrote:
On Thursday, 31 October 2019 16:27:12 UTC+1, Rick C wrote:
On Thursday, October 31, 2019 at 4:33:20 AM UTC-4,
klaus.k...@gmail.com wrote:
Hi

I am working on a US variant on a small pump (below 75W)

But, I am unable to find the percentage of distribution of
different US mains voltage

My guess is that most is 115V, but I have also heard about 208V
(phase phase), and 240V (120V, 180 degrees phase inverted)

Any inputs of how much is 115V grid, how much 208, how much
240V?

A large percentage of commercial installations are 208 volts
rather than 240. I charge my car at level 2 chargers in lots of
locations and some 90% of them are 208 volts (give or take)
rather than 240. Instead of getting 7 kW charging rate, I
usually see 6 or below because of the voltage.


Good info

Commercial, would that be businesses, hotels, or what?

Pretty much yes. Hotels, hospital parking deck, retail food store,
retirement community parking. These are the ones I recall off the
top of my head. I'm sure I've seen 240 volt level 2 charging, but I
don't recall where that would have been.


Even among those commercial operations most of the small ones will only
have 120/240V wiring, two-phase 180 degrees. 208V three-phase is pricey,
needs a special transformer and is typically only used in larger places
or ones with a high electric energy demand.

It's not really a special transformer, but more transformers for light/medium
capacity 3 phase. If you're comparing 240/120 split-phase to 3 phase you;d
be talking about light capacity 3 phase. To get that here in the US, typically
they use two transformers, while for split-phase you only need one. For
medium capacity 3 phase, they use three transformers. You see that on
street poles all over.

I have often wondered, why you have three separate pigs in the pole to
get 3 phases. Why don't you use a true 3 phase transformer ? Since
some of the flux cancel out in a true three phase transformer, the
total amount of iron is less than for three separate single phase
transformers.

How much that added cost affects you as the customer,
will depend on the actual power company, but somebody has to pay for it,
one way or the other. Which is one reason that 3 phase into homes makes
no sense to me.

 

[Whoey Louie]

On Saturday, November 2, 2019 at 12:04:13 PM UTC-4, Whoey Louie wrote:

On Saturday, November 2, 2019 at 10:55:41 AM UTC-4, Joerg wrote:
On 2019-10-31 17:10, Rick C wrote:
On Thursday, October 31, 2019 at 7:38:49 PM UTC-4,
klaus.k...@gmail.com wrote:
On Thursday, 31 October 2019 16:27:12 UTC+1, Rick C wrote:
On Thursday, October 31, 2019 at 4:33:20 AM UTC-4,
klaus.k...@gmail.com wrote:
Hi

I am working on a US variant on a small pump (below 75W)

But, I am unable to find the percentage of distribution of
different US mains voltage

My guess is that most is 115V, but I have also heard about 208V
(phase phase), and 240V (120V, 180 degrees phase inverted)

Any inputs of how much is 115V grid, how much 208, how much
240V?

A large percentage of commercial installations are 208 volts
rather than 240. I charge my car at level 2 chargers in lots of
locations and some 90% of them are 208 volts (give or take)
rather than 240. Instead of getting 7 kW charging rate, I
usually see 6 or below because of the voltage.


Good info

Commercial, would that be businesses, hotels, or what?

Pretty much yes. Hotels, hospital parking deck, retail food store,
retirement community parking. These are the ones I recall off the
top of my head. I'm sure I've seen 240 volt level 2 charging, but I
don't recall where that would have been.


Even among those commercial operations most of the small ones will only
have 120/240V wiring, two-phase 180 degrees. 208V three-phase is pricey,
needs a special transformer and is typically only used in larger places
or ones with a high electric energy demand.

It's not really a special transformer, but more transformers for light/medium
capacity 3 phase. If you're comparing 240/120 split-phase to 3 phase you;d
be talking about light capacity 3 phase. To get that here in the US, typically
they use two transformers, while for split-phase you only need one. For
medium capacity 3 phase, they use three transformers. You see that on
street poles all over. How much that added cost affects you as the customer,
will depend on the actual power company, but somebody has to pay for it,
one way or the other. Which is one reason that 3 phase into homes makes
no sense to me.






Klaus, in the US you will usually see ground distributed to 240V outlets
even though it is often not used by the equipment that is plugged in. So
there are four connections, 120V phase 1, 120V phase 2, neutral,
protective ground. What you need to keep in mind is that such outlets
are generally fused at much more than the usual 15A or 20A. So the cable
from the outlet to the fuse in your pump circuitry must be rated for the
highest expected circuit breaker current rating.

You will see ground at all receptacles installed for about a half century
here in the USA, unless they violated code.




Older homes can have 240V three-prong outlets where you don't have
neutral, for example for dryers and in the kitchen for a free-standing
oven/range. AFAIK that is no longer allowed for new construction in many
states.

It's actually the other way around. Prior to a few decades ago in the US
it was permitted and common practice to use the neutral in a dryer or
similar connection as the equipment ground too. Since then a four wire circuit
that has an EGC is required for new circuits.





Hardwired equipment such as a built-in kitchen oven or range often does
not have neutral either but there you cannot legally connect anything
else without having an electrician run cable and a new outlet.

--
Regards, Joerg


Not so sure about that. I've never seen an oven, range, etc circuit
that didn't have a neutral. There probably are some, but I don't think
it's common.

To clarify the above, while I haven't seen ovens or ranges that don't
use a neutral, what you say is true of other circuits, eg water heaters,
well pumps and the like. The issue with ovens, ranges, dryers, etc
is that every one I've seen has some 120V requirement, eg light bulbs
in older units and electronics in modern ones. They could use 240V bulbs
and run the electronics off 240V, but for whatever reasons they don't
seem to do so.

 

[Whoey Louie]

On Saturday, November 2, 2019 at 10:55:41 AM UTC-4, Joerg wrote:

On 2019-10-31 17:10, Rick C wrote:
On Thursday, October 31, 2019 at 7:38:49 PM UTC-4,
klaus.k...@gmail.com wrote:
On Thursday, 31 October 2019 16:27:12 UTC+1, Rick C wrote:
On Thursday, October 31, 2019 at 4:33:20 AM UTC-4,
klaus.k...@gmail.com wrote:
Hi

I am working on a US variant on a small pump (below 75W)

But, I am unable to find the percentage of distribution of
different US mains voltage

My guess is that most is 115V, but I have also heard about 208V
(phase phase), and 240V (120V, 180 degrees phase inverted)

Any inputs of how much is 115V grid, how much 208, how much
240V?

A large percentage of commercial installations are 208 volts
rather than 240. I charge my car at level 2 chargers in lots of
locations and some 90% of them are 208 volts (give or take)
rather than 240. Instead of getting 7 kW charging rate, I
usually see 6 or below because of the voltage.


Good info

Commercial, would that be businesses, hotels, or what?

Pretty much yes. Hotels, hospital parking deck, retail food store,
retirement community parking. These are the ones I recall off the
top of my head. I'm sure I've seen 240 volt level 2 charging, but I
don't recall where that would have been.


Even among those commercial operations most of the small ones will only
have 120/240V wiring, two-phase 180 degrees. 208V three-phase is pricey,
needs a special transformer and is typically only used in larger places
or ones with a high electric energy demand.

It's not really a special transformer, but more transformers for light/medium
capacity 3 phase. If you're comparing 240/120 split-phase to 3 phase you;d
be talking about light capacity 3 phase. To get that here in the US, typically
they use two transformers, while for split-phase you only need one. For
medium capacity 3 phase, they use three transformers. You see that on
street poles all over. How much that added cost affects you as the customer,
will depend on the actual power company, but somebody has to pay for it,
one way or the other. Which is one reason that 3 phase into homes makes
no sense to me.

Klaus, in the US you will usually see ground distributed to 240V outlets
even though it is often not used by the equipment that is plugged in. So
there are four connections, 120V phase 1, 120V phase 2, neutral,
protective ground. What you need to keep in mind is that such outlets
are generally fused at much more than the usual 15A or 20A. So the cable
from the outlet to the fuse in your pump circuitry must be rated for the
highest expected circuit breaker current rating.

You will see ground at all receptacles installed for about a half century
here in the USA, unless they violated code.

Older homes can have 240V three-prong outlets where you don't have
neutral, for example for dryers and in the kitchen for a free-standing
oven/range. AFAIK that is no longer allowed for new construction in many
states.

It's actually the other way around. Prior to a few decades ago in the US
it was permitted and common practice to use the neutral in a dryer or
similar connection as the equipment ground too. Since then a four wire circuit
that has an EGC is required for new circuits.

Hardwired equipment such as a built-in kitchen oven or range often does
not have neutral either but there you cannot legally connect anything
else without having an electrician run cable and a new outlet.

--
Regards, Joerg

Not so sure about that. I've never seen an oven, range, etc circuit
that didn't have a neutral. There probably are some, but I don't think
it's common.

 

[Whoey Louie]

On Saturday, November 2, 2019 at 12:28:29 PM UTC-4, upsid...@downunder.com wrote:

On Sat, 2 Nov 2019 09:04:08 -0700 (PDT), Whoey Louie
trader4@optonline.net> wrote:

On Saturday, November 2, 2019 at 10:55:41 AM UTC-4, Joerg wrote:
On 2019-10-31 17:10, Rick C wrote:
On Thursday, October 31, 2019 at 7:38:49 PM UTC-4,
klaus.k...@gmail.com wrote:
On Thursday, 31 October 2019 16:27:12 UTC+1, Rick C wrote:
On Thursday, October 31, 2019 at 4:33:20 AM UTC-4,
klaus.k...@gmail.com wrote:
Hi

I am working on a US variant on a small pump (below 75W)

But, I am unable to find the percentage of distribution of
different US mains voltage

My guess is that most is 115V, but I have also heard about 208V
(phase phase), and 240V (120V, 180 degrees phase inverted)

Any inputs of how much is 115V grid, how much 208, how much
240V?

A large percentage of commercial installations are 208 volts
rather than 240. I charge my car at level 2 chargers in lots of
locations and some 90% of them are 208 volts (give or take)
rather than 240. Instead of getting 7 kW charging rate, I
usually see 6 or below because of the voltage.


Good info

Commercial, would that be businesses, hotels, or what?

Pretty much yes. Hotels, hospital parking deck, retail food store,
retirement community parking. These are the ones I recall off the
top of my head. I'm sure I've seen 240 volt level 2 charging, but I
don't recall where that would have been.


Even among those commercial operations most of the small ones will only
have 120/240V wiring, two-phase 180 degrees. 208V three-phase is pricey,
needs a special transformer and is typically only used in larger places
or ones with a high electric energy demand.

It's not really a special transformer, but more transformers for light/medium
capacity 3 phase. If you're comparing 240/120 split-phase to 3 phase you;d
be talking about light capacity 3 phase. To get that here in the US, typically
they use two transformers, while for split-phase you only need one. For
medium capacity 3 phase, they use three transformers. You see that on
street poles all over.

I have often wondered, why you have three separate pigs in the pole to
get 3 phases. Why don't you use a true 3 phase transformer ? Since
some of the flux cancel out in a true three phase transformer, the
total amount of iron is less than for three separate single phase
transformers.

How much that added cost affects you as the customer,
will depend on the actual power company, but somebody has to pay for it,
one way or the other. Which is one reason that 3 phase into homes makes
no sense to me.

IDK, but my guess would be that one transformer of the same capacity as
the three separate ones would be so heavy that it would be a balancing
problem on the pole and they don't want leaning, falling over poles.

 

[Tom Gardner]

On 02/11/19 15:24, Whoey Louie wrote:

On Saturday, November 2, 2019 at 10:10:35 AM UTC-4, Tom Gardner wrote:
On 02/11/19 13:51, Whoey Louie wrote:
On Saturday, November 2, 2019 at 3:48:09 AM UTC-4, upsid...@downunder.com wrote:
On Fri, 1 Nov 2019 17:19:12 -0700 (PDT), Whoey Louie
trader4@optonline.net> wrote:

On Friday, November 1, 2019 at 12:34:52 PM UTC-4, keith wright wrote:
On Friday, 1 November 2019 08:32:00 UTC-7, Rick C wrote:
...

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.
...

Strictly speaking the circuits are usually 30Amp (wired as a ring main) with a local fuse inside the plug that depends upon the load. It can be up to 13A.

kw

So, instead of conductors being smaller than what is typically used in the US
where we have 15a or 20a, the conductors are actually larger. Higher
voltage and higher current. Thanks for clearing that up.

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Must be fun when the one breaker trips and everything in the house goes
off, including all the lights.

Except of course it doesn't.

Traditionally each floor in a suburban house has one ring main
for the sockets and another for the lights. High current devices
have a dedicated spur from the distribution point.

I was going by what someone who lives there posted. And even by what
you say, if it's a one floor house, then all the lighting circuits go
out. In the US you'd lose one lighting circuit, not all of them.

Yes, that's what happens.

There's usually enough light from other sources that you
aren't blind, but you need a torch to replace the fuse
wire in the holder.

Fuses rarely go nowadays. OTOH at my mother's house a
breaker seems to pop whenever an incandescant light
fails. I don't understand that.

Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.


I would expect that both fuses must blow at the same time. With a ring,
the current would be about evenly split between the two sources. As
soon as one fuse blows, the current in the other fuse would double and
it will blow.

Except the presumption is wrong.

Again, I just went by what the other poster claimed, so I guess he's
full of baloney.

Let's say mistaken in this case.

Are you still really using fuses, not breakers? Here
for new work, circuits for living space have to be on AFCI breakers now
too, for arc fault protection.

Depends on the age of the installation.

I said for "new work". And that's what the code is, you have to comply
with current code for new work it doesn't depend on the age of what's
already there.




Never heard of AFCI breakers, but that's my ignorance.

Google broken?

Irrelevant to whether I had heard of them

It seems that we don't need them here because we have lower
currents due to higher voltages.

 

[Tom Gardner]

On 02/11/19 18:14, Rick C wrote:

On Saturday, November 2, 2019 at 1:57:09 PM UTC-4, Tom Gardner wrote:
On 02/11/19 15:24, Whoey Louie wrote:
On Saturday, November 2, 2019 at 10:10:35 AM UTC-4, Tom Gardner wrote:

Never heard of AFCI breakers, but that's my ignorance.

Google broken?

Irrelevant to whether I had heard of them

It seems that we don't need them here because we have lower currents due to
higher voltages.

Lol! The things people say out of ignorance.

Indeed. The "seems" in my statement indicates my ignorance and
lack of understanding of that contention.

I merely saw the statement in the wackypedia article.

An AFCI breaker detects dangerous conditions that are not detected by either
GFCI (RCD in your country?) or overload breakers. If a wire is worn or
chewed by rodents or just a loose connection, it will generate a dangerous
arc with local heating. This device detects the transients in current
consistent with faults but not normal operation.

In your country they appear to be called arc-fault detection device (AFDD).

 

[Whoey Louie]

On Saturday, November 2, 2019 at 1:59:56 PM UTC-4, Rick C wrote:

On Saturday, November 2, 2019 at 10:55:41 AM UTC-4, Joerg wrote:
On 2019-10-31 17:10, Rick C wrote:
On Thursday, October 31, 2019 at 7:38:49 PM UTC-4,
klaus.k...@gmail.com wrote:
On Thursday, 31 October 2019 16:27:12 UTC+1, Rick C wrote:
On Thursday, October 31, 2019 at 4:33:20 AM UTC-4,
klaus.k...@gmail.com wrote:
Hi

I am working on a US variant on a small pump (below 75W)

But, I am unable to find the percentage of distribution of
different US mains voltage

My guess is that most is 115V, but I have also heard about 208V
(phase phase), and 240V (120V, 180 degrees phase inverted)

Any inputs of how much is 115V grid, how much 208, how much
240V?

A large percentage of commercial installations are 208 volts
rather than 240. I charge my car at level 2 chargers in lots of
locations and some 90% of them are 208 volts (give or take)
rather than 240. Instead of getting 7 kW charging rate, I
usually see 6 or below because of the voltage.


Good info

Commercial, would that be businesses, hotels, or what?

Pretty much yes. Hotels, hospital parking deck, retail food store,
retirement community parking. These are the ones I recall off the
top of my head. I'm sure I've seen 240 volt level 2 charging, but I
don't recall where that would have been.


Even among those commercial operations most of the small ones will only
have 120/240V wiring, two-phase 180 degrees. 208V three-phase is pricey,
needs a special transformer and is typically only used in larger places
or ones with a high electric energy demand.

Not sure what you mean by "small". A "small" hospital? I suppose a retail food store could be small and the ones I've been to were small but had 208 volts at the car chargers.

I think you don't realize how pervasive 3 phase power is in the US. Why would it take a special transformer? It's three phase on the distribution line, three phase on both sides of the transformer.

It depends on what you call special. In the US light capacity 3 phase,
they typically get 3 phase using just two pole transformers. Nothing really
special about them, they just have to be the right ones. For higher
capacity then they use three separate pole transformers. You see see both
of those commonly used. But the fact that you need two transformers for
light capacity 3 phase is another argument for why it makes no sense for
homes.

Klaus, in the US you will usually see ground distributed to 240V outlets
even though it is often not used by the equipment that is plugged in. So
there are four connections, 120V phase 1, 120V phase 2, neutral,
protective ground. What you need to keep in mind is that such outlets
are generally fused at much more than the usual 15A or 20A. So the cable
from the outlet to the fuse in your pump circuitry must be rated for the
highest expected circuit breaker current rating.

It entirely depends on the connector. Some have a neutral pin, some don't. Standard 120 volt outlets here have a neutral pin and a ground, but because our 240 volt line is two hots, the NEMA 6 series of connectors have no neutral, only a protective earth ground.

It's actually properly called the "equipment grounding conductor".

Probably more common are the NEMA 14 series connectors which include a neutral and a ground for 120/240 volt applications meaning it can provide both 120 and 240 volts. That's the only reason to include the neutral, to provide 120 volts.


Older homes can have 240V three-prong outlets where you don't have
neutral, for example for dryers and in the kitchen for a free-standing
oven/range. AFAIK that is no longer allowed for new construction in many
states.

This is not accurate. The TT-30 connectors used for older dryers have a neutral, but no protective ground. They are deprecated, but not required to be removed. It is now expected such a connection would include a separate protective ground for the frame of the appliance. No new appliance will support this connection method.

That's not true. Dryers and such sold today support being used with
either an old 3 wire cord and receptacle or the newer 4 wired cord and
receptacle. If they didn't people would have to run a new circuit just
to replace their appliance.

Hardwired equipment such as a built-in kitchen oven or range often does
not have neutral either but there you cannot legally connect anything
else without having an electrician run cable and a new outlet.

Ranges are typically hard wired without a connector.

That's not true either. Ranges are typically free standing and connected
with a cord.




Dishwashers I believe are now required to be on an outlet, at least that is what I was told.

That's not true either.



They are also 120, not 240 volts.

Bottom line is for a 75 watt device there is no reason to consider 240 volts for US usage. Here appliances use 120 volts unless there is a compelling need for higher power than can be found in a typical outlet, 120 volts, 15 amps. For "continuous" loads the current must be derated to 80%. Not sure if your pump would be a continuous load or not, but 75 watts is well within the 80% rating.

If you try to sell a 240 volt pump here it will be a specialty product requiring a special wiring run to bring power to it.

--

Rick C.

----- Get 1,000 miles of free Supercharging
----- Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Saturday, November 2, 2019 at 10:55:41 AM UTC-4, Joerg wrote:

On 2019-10-31 17:10, Rick C wrote:
On Thursday, October 31, 2019 at 7:38:49 PM UTC-4,
klaus.k...@gmail.com wrote:
On Thursday, 31 October 2019 16:27:12 UTC+1, Rick C wrote:
On Thursday, October 31, 2019 at 4:33:20 AM UTC-4,
klaus.k...@gmail.com wrote:
Hi

I am working on a US variant on a small pump (below 75W)

But, I am unable to find the percentage of distribution of
different US mains voltage

My guess is that most is 115V, but I have also heard about 208V
(phase phase), and 240V (120V, 180 degrees phase inverted)

Any inputs of how much is 115V grid, how much 208, how much
240V?

A large percentage of commercial installations are 208 volts
rather than 240. I charge my car at level 2 chargers in lots of
locations and some 90% of them are 208 volts (give or take)
rather than 240. Instead of getting 7 kW charging rate, I
usually see 6 or below because of the voltage.


Good info

Commercial, would that be businesses, hotels, or what?

Pretty much yes. Hotels, hospital parking deck, retail food store,
retirement community parking. These are the ones I recall off the
top of my head. I'm sure I've seen 240 volt level 2 charging, but I
don't recall where that would have been.


Even among those commercial operations most of the small ones will only
have 120/240V wiring, two-phase 180 degrees. 208V three-phase is pricey,
needs a special transformer and is typically only used in larger places
or ones with a high electric energy demand.

Not sure what you mean by "small". A "small" hospital? I suppose a retail food store could be small and the ones I've been to were small but had 208 volts at the car chargers.

I think you don't realize how pervasive 3 phase power is in the US. Why would it take a special transformer? It's three phase on the distribution line, three phase on both sides of the transformer.

Klaus, in the US you will usually see ground distributed to 240V outlets
even though it is often not used by the equipment that is plugged in. So
there are four connections, 120V phase 1, 120V phase 2, neutral,
protective ground. What you need to keep in mind is that such outlets
are generally fused at much more than the usual 15A or 20A. So the cable
from the outlet to the fuse in your pump circuitry must be rated for the
highest expected circuit breaker current rating.

It entirely depends on the connector. Some have a neutral pin, some don't. Standard 120 volt outlets here have a neutral pin and a ground, but because our 240 volt line is two hots, the NEMA 6 series of connectors have no neutral, only a protective earth ground.

Probably more common are the NEMA 14 series connectors which include a neutral and a ground for 120/240 volt applications meaning it can provide both 120 and 240 volts. That's the only reason to include the neutral, to provide 120 volts.

Older homes can have 240V three-prong outlets where you don't have
neutral, for example for dryers and in the kitchen for a free-standing
oven/range. AFAIK that is no longer allowed for new construction in many
states.

This is not accurate. The TT-30 connectors used for older dryers have a neutral, but no protective ground. They are deprecated, but not required to be removed. It is now expected such a connection would include a separate protective ground for the frame of the appliance. No new appliance will support this connection method.

Hardwired equipment such as a built-in kitchen oven or range often does
not have neutral either but there you cannot legally connect anything
else without having an electrician run cable and a new outlet.

Ranges are typically hard wired without a connector. Dishwashers I believe are now required to be on an outlet, at least that is what I was told. They are also 120, not 240 volts.

Bottom line is for a 75 watt device there is no reason to consider 240 volts for US usage. Here appliances use 120 volts unless there is a compelling need for higher power than can be found in a typical outlet, 120 volts, 15 amps. For "continuous" loads the current must be derated to 80%. Not sure if your pump would be a continuous load or not, but 75 watts is well within the 80% rating.

If you try to sell a 240 volt pump here it will be a specialty product requiring a special wiring run to bring power to it.

--

Rick C.

----- Get 1,000 miles of free Supercharging
----- Tesla referral code - https://ts.la/richard11209

 

[Whoey Louie]

On Saturday, November 2, 2019 at 1:57:09 PM UTC-4, Tom Gardner wrote:

On 02/11/19 15:24, Whoey Louie wrote:
On Saturday, November 2, 2019 at 10:10:35 AM UTC-4, Tom Gardner wrote:
On 02/11/19 13:51, Whoey Louie wrote:
On Saturday, November 2, 2019 at 3:48:09 AM UTC-4, upsid...@downunder..com wrote:
On Fri, 1 Nov 2019 17:19:12 -0700 (PDT), Whoey Louie
trader4@optonline.net> wrote:

On Friday, November 1, 2019 at 12:34:52 PM UTC-4, keith wright wrote:
On Friday, 1 November 2019 08:32:00 UTC-7, Rick C wrote:
...

Your assumption that a kettle would boil twice as fast is based on an assumption that the same size wire and so the same current capacity would be used. I believe in the UK circuits can be typically 9 or 13 amps, so smaller than the 15 or 20 we typically use.
...

Strictly speaking the circuits are usually 30Amp (wired as a ring main) with a local fuse inside the plug that depends upon the load. It can be up to 13A.

kw

So, instead of conductors being smaller than what is typically used in the US
where we have 15a or 20a, the conductors are actually larger. Higher
voltage and higher current. Thanks for clearing that up.

The idea behind the old UK ring mains system is that a single feed is
zigzagging through all rooms and this will reduce the amount of cables
required compared to individual cabling from the distribution point
with individual cables to each room as used in most countries.

Must be fun when the one breaker trips and everything in the house goes
off, including all the lights.

Except of course it doesn't.

Traditionally each floor in a suburban house has one ring main
for the sockets and another for the lights. High current devices
have a dedicated spur from the distribution point.

I was going by what someone who lives there posted. And even by what
you say, if it's a one floor house, then all the lighting circuits go
out. In the US you'd lose one lighting circuit, not all of them.

Yes, that's what happens.

There's usually enough light from other sources that you
aren't blind, but you need a torch to replace the fuse
wire in the holder.

Fuses rarely go nowadays. OTOH at my mother's house a
breaker seems to pop whenever an incandescant light
fails. I don't understand that.


Due to the long zigzagging cable, the voltage loss would be large in
the far end. To reduce the losses, the far end of the cable is
returned back to the feed point.

Of course there must be fuses at both ends of the ring. Even if one
fuse is blown, current would be flowing from the opposite end with
larger voltage drops. Of course, if the short is still persisting, it
will also blow the other fuse.


I would expect that both fuses must blow at the same time. With a ring,
the current would be about evenly split between the two sources. As
soon as one fuse blows, the current in the other fuse would double and
it will blow.

Except the presumption is wrong.

Again, I just went by what the other poster claimed, so I guess he's
full of baloney.

Let's say mistaken in this case.


Are you still really using fuses, not breakers? Here
for new work, circuits for living space have to be on AFCI breakers now
too, for arc fault protection.

Depends on the age of the installation.

I said for "new work". And that's what the code is, you have to comply
with current code for new work it doesn't depend on the age of what's
already there.




Never heard of AFCI breakers, but that's my ignorance.

Google broken?

Irrelevant to whether I had heard of them

It seems that we don't need them here because we have lower
currents due to higher voltages.

Not sure lower current buys you anything. You still have a similar amount
of power to fuel an arc fault and the higher the voltage, the easier it is
to arc. It doesn't take all that much to start a fire.