Laser printer draws current in a spike, what for?

[Andrew Gabriel]

In article <cgvv6622lj3@news1.newsguy.com>,
phil-news-nospam@ipal.net writes:

We do have 240 volts. The problem is that we also have the NFPA that
publishes the NEC which in 210.6(A)(2) restricts the voltage for cord
and plug equipment to a maximum of 120 volts relative to ground, thus
disallowing the use of the 240 volt connection for the typical laser
printer. Of course one might get around this if they say it is a 26A
load instead of a 8A (relative to 120 volts).

I guess I should put this in the "favorite beef with the NEC" thread.

I don't know that this would affect it all that much, but I've also
heard that in UK, available fault current at homes tends to be higher
than in the US (one transformer serving a whole block of homes instead
of the typical 1 to 4 in the US). I'm not sure I'd really like having
higher available fault current.

EU breakers have a magnetic tripping component to handle fault
current interruption within half a mains cycle, in addition to
the thermal tripping component for overload protection. Our
residential breakers typically have a breaking capacity of
6kA, and this is sometimes increased to 10kA by use of specific
suppliers cutout (main fuse type). Higher breaking capacity breakers
are available (e.g. 10kA), but not normally required in residential
situations.

--
Andrew Gabriel

 

[Andrew Gabriel]

In article <877jrgl7gl.fld@barrow.com>,
floyd@barrow.com (Floyd L. Davidson) writes:

andrew@cucumber.demon.co.uk (Andrew Gabriel) wrote:
In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
According to US sources, problems such as you report never occur, and
they don't need to implement the IEC versions of those ENs as US
standards. So you are actually just imagining the flicker. (;-)

The irony is this is quite common in the US, but I've never seen
it happening in a 240V country ;-)

Well... obviously the current is halved, but...

And the percentage voltage drop is quartered...

A laser printer that dims the lights???? Jus how common is
that, really?

Also, we don't run fixed lighting from same circuits as power
outlets.

--
Andrew Gabriel

 

In alt.engineering.electrical phil-news-nospam@ipal.net wrote:
| In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk> wrote:
|
| | In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
| | John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
| |> According to US sources, problems such as you report never occur, and
| |> they don't need to implement the IEC versions of those ENs as US
| |> standards. So you are actually just imagining the flicker. (;-)
| |
| | The irony is this is quite common in the US, but I've never seen
| | it happening in a 240V country ;-)
|
| We do have 240 volts. The problem is that we also have the NFPA that
| publishes the NEC which in 210.6(A)(2) restricts the voltage for cord
| and plug equipment to a maximum of 120 volts relative to ground, thus
| disallowing the use of the 240 volt connection for the typical laser
| printer. Of course one might get around this if they say it is a 26A
| load instead of a 8A (relative to 120 volts).

While editing and re-editing, the "1440 watt" specified in 210.6(A)(2)
got dropped from my post and I intended to mention it.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

[Jim Thompson]

On 30 Aug 2004 19:29:10 GMT, phil-news-nospam@ipal.net wrote:

In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk> wrote:

| In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
| John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
|> According to US sources, problems such as you report never occur, and
|> they don't need to implement the IEC versions of those ENs as US
|> standards. So you are actually just imagining the flicker. (;-)
|
| The irony is this is quite common in the US, but I've never seen
| it happening in a 240V country ;-)

We do have 240 volts. The problem is that we also have the NFPA that
publishes the NEC which in 210.6(A)(2) restricts the voltage for cord
and plug equipment to a maximum of 120 volts relative to ground, thus
disallowing the use of the 240 volt connection for the typical laser
printer.

Huh? How about electric clothes dryers? And our 240VAC is actually
120-0-120 so the cord is never more than 120V relative to ground.

Of course one might get around this if they say it is a 26A
load instead of a 8A (relative to 120 volts).

I guess I should put this in the "favorite beef with the NEC" thread.

I don't know that this would affect it all that much, but I've also
heard that in UK, available fault current at homes tends to be higher
than in the US (one transformer serving a whole block of homes instead
of the typical 1 to 4 in the US). I'm not sure I'd really like having
higher available fault current.

Where I am there are two houses to a transformer (200A service
typical).

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Pooh Bear]

John Woodgate wrote:

According to US sources, problems such as you report never occur, and
they don't need to implement the IEC versions of those ENs as US
standards. So you are actually just imagining the flicker. (;-)

Tssk @ you John.

You're suggesting that the IEC has 'versions' of the ENs ? Other way surely
!


Graham

 

[Louis Bybee]

<phil-news-nospam@ipal.net> wrote in message
news:cgvv6622lj3@news1.newsguy.com...

In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk
wrote:

| In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
| John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
|> According to US sources, problems such as you report never occur, and
|> they don't need to implement the IEC versions of those ENs as US
|> standards. So you are actually just imagining the flicker. (;-)
|
| The irony is this is quite common in the US, but I've never seen
| it happening in a 240V country ;-)

We do have 240 volts. The problem is that we also have the NFPA that
publishes the NEC which in 210.6(A)(2) restricts the voltage for cord
and plug equipment to a maximum of 120 volts relative to ground, thus
disallowing the use of the 240 volt connection for the typical laser
printer. Of course one might get around this if they say it is a 26A
load instead of a 8A (relative to 120 volts).

I guess I should put this in the "favorite beef with the NEC" thread.

I don't know that this would affect it all that much, but I've also
heard that in UK, available fault current at homes tends to be higher
than in the US (one transformer serving a whole block of homes instead
of the typical 1 to 4 in the US). I'm not sure I'd really like having
higher available fault current.

--
--------------------------------------------------------------------------
---
| Phil Howard KA9WGN |

210.6(A) applies to dwelling and guest rooms of hotels, motels, etc. This
article wouldn't be applicable to homes, and office environments. It also
relates to voltage between conductors. Ground isn't referenced in 210.6(A).

210.6(A)(2) restricts to 1,440 va and below, or 12 amps at 120 volts again
in dwelling and guest rooms of hotels, motels, etc.

As you alluded there may well be Laser Printers that would qualify to be
used in dwelling and guest rooms of hotels, motels, etc. at 240 volts due to
being rated in excess of the above limitations. However, most I've seen for
use in USA are rated at 120 volts.

210.6(C) would allow the Laser Printers to be utilized at 240 volts in
dwellings, offices, etc. Again most consumer Laser Printers are sold in a
120 volt configuration.

Most 240 volt circuits, in areas of the USA that I'm familiar with, are 120
volts with respect to ground with the exception of the wild leg of a 240
volt 3 phase delta, with one leg center tapped to ground. In that case the
wild leg usually isn't present in panels designed for single phase loads.

The voltage drop/lights blinking issue that the OP brought up is for the
most part related to older style Laser Printers, and in many cases is
usually associated with circuits that are likely in trouble without the
addition of the printer. I have also seen older Laser Printers that had much
worse numbers than reported by the OP.

When confronted with such a condition I usually recommend a newer printer,
and/or an electrician to install a new circuit, or break up the existing
load between circuits to provide as light a load as possible on the printer
circuit.

It absolutely boggles my mind to see the spendy installations undertaken
without the design services of an engineer, or knowledgeable electrician
before the installation commences.

Never enough time or money to do it right the first time, but always enough
after the fact! :-]

Louis--
*********************************************
Remove the two fish in address to respond

 

[John Woodgate]

I read in sci.electronics.design that Pooh Bear <rabbitsfriendsandrelati
ons@hotmail.com> wrote (in <4133D32E.359999E9@hotmail.com&gt about 'Laser
printer draws current in a spike, what for?', on Tue, 31 Aug 2004:

John Woodgate wrote:

According to US sources, problems such as you report never occur, and
they don't need to implement the IEC versions of those ENs as US
standards. So you are actually just imagining the flicker. (;-)

Tssk @ you John.

You're suggesting that the IEC has 'versions' of the ENs ? Other way surely
!

Well, I don't think that 'version' is all that misleading. And in fact
the standards process is becoming more and more interactive. A lot of
CISPR 22 and 24 originated in CENELEC.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

In alt.engineering.electrical Jim Thompson <thegreatone@example.com> wrote:
| On 30 Aug 2004 19:29:10 GMT, phil-news-nospam@ipal.net wrote:
|
|>In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk> wrote:
|>
|>| In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
|>| John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
|>|> According to US sources, problems such as you report never occur, and
|>|> they don't need to implement the IEC versions of those ENs as US
|>|> standards. So you are actually just imagining the flicker. (;-)
|>|
|>| The irony is this is quite common in the US, but I've never seen
|>| it happening in a 240V country ;-)
|>
|>We do have 240 volts. The problem is that we also have the NFPA that
|>publishes the NEC which in 210.6(A)(2) restricts the voltage for cord
|>and plug equipment to a maximum of 120 volts relative to ground, thus
|>disallowing the use of the 240 volt connection for the typical laser
|>printer.
|
| Huh? How about electric clothes dryers? And our 240VAC is actually
| 120-0-120 so the cord is never more than 120V relative to ground.

Sorry, I accidentally omitted that it applies to loads under 1440 watts.
Above that, most loads need a dedicated circuit, anyway. Personally, I
would prefer lowing the 1440 watt figure of 210.6(A)(2) or even getting
rid of that limit (or setting it at 300 volts).

In a house I'll be building in a few years, I'm going to see if I can
get away with putting in lots of 6-20R's for 240 volts in many places.
Hopefully 210.6(A)(2) won't be interpreted to get in the way of that.
I will have a couple over-1440 watt appliances, so hopefully it will
be OK.


| Where I am there are two houses to a transformer (200A service
| typical).

I've seen much variation. My grandfather had 3 transformers to himself.
But he had three phase.

One house I used to live in had 1 transformer to itself because it was
an add-on to a development that wasn't originally planned. I've also
seen as many as 12 houses run from 1 transformer and it wasn't very big,
either (looked to be 75 to 100 kVA at most). But if those houses had
60 amp service, it could work.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

In alt.engineering.electrical Louis Bybee <louistroutbybee@comcasttrout.net> wrote:

| 210.6(A) applies to dwelling and guest rooms of hotels, motels, etc. This
| article wouldn't be applicable to homes, and office environments. It also
| relates to voltage between conductors. Ground isn't referenced in 210.6(A).
|
| 210.6(A)(2) restricts to 1,440 va and below, or 12 amps at 120 volts again
| in dwelling and guest rooms of hotels, motels, etc.

Homes are considered dwellings.


| Most 240 volt circuits, in areas of the USA that I'm familiar with, are 120
| volts with respect to ground with the exception of the wild leg of a 240
| volt 3 phase delta, with one leg center tapped to ground. In that case the
| wild leg usually isn't present in panels designed for single phase loads.

And most of the homes don't have the wild leg at all.

But some places have 208Y/120, so no 240 at all, but it is 208.


| Never enough time or money to do it right the first time, but always enough
| after the fact! :-]

It's called "wait for a disaster to happen".

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk> wrote:
| In article <877jrgl7gl.fld@barrow.com>,
| floyd@barrow.com (Floyd L. Davidson) writes:
|> andrew@cucumber.demon.co.uk (Andrew Gabriel) wrote:
|>>In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
|>> John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
|>>> According to US sources, problems such as you report never occur, and
|>>> they don't need to implement the IEC versions of those ENs as US
|>>> standards. So you are actually just imagining the flicker. (;-)
|>>
|>>The irony is this is quite common in the US, but I've never seen
|>>it happening in a 240V country ;-)
|>
|> Well... obviously the current is halved, but...
|
| And the percentage voltage drop is quartered...
|
|> A laser printer that dims the lights???? Jus how common is
|> that, really?
|
| Also, we don't run fixed lighting from same circuits as power
| outlets.

Now days, most homes here have lighting split from outlets. I have to
remember way way back to where they were shared.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

[bushbadee]

That is also a problem with tv sets.
When the power first comes on the cold filimants draw a large surge.
What you can do is soldeir a surgistor in line with the device that heats
the drum.
When you turn it on at first the surgistor has a high impedance and as it
warms up it resistance drops to a low value. This reduces or eliminates the
inrush current (Also some times seen on large transformers)
There are also surgistors that have built in points that close when the
device heats up so there is no voltage across the device. When the power
shuts off, the points open up to be ready for the next surge.

If you have an oscilliscope, I am assuming you would know how to do this.





"~Dude17~" <dude17@sacbeemail.com> wrote in message
news:b959931f.0408290758.2592a92d@posting.google.com...

X-No-Archive: Yes

I've got a laser printer that draws current in spikes and it
makes the lights flicker as well as causing a UPS on the same circuit
to switch over to battery due to excessive dV/dT. Unfortunately, I
don't have a way of putting the printer on its own circuit unless I
want to use a long extension cord.

When it's in sleep state, it draws about 0.22A. When I print
something, it draws about 8A RMS to heat up. After it's done
printing, it stays in "ready to print" state for about ten minutes
before going to sleep and this is where problem starts.

Had the printer for a while, but I finally bothered to check it out on
scope.

I captured the event on my storage oscilloscope and this is what I
found:

At the start of cycle it draws 26A RMS for about 32mS or two cycles
and tapers down to 8.5A RMS after 550mS. Between the start and 550mS,
there's two spikes of about 8mS where current is only drawn from half
of the cycle. After 550mS, the current draw drops to 0.22A RMS, then
starts this whole cycle again after 15 seconds.

If you're a visual type of person, here's the actual capture:
http://dude17site.tripod.com/printer.html

Is there a reason it needs to draw current in this pattern instead of
spreading it out over a longer period of time?

 

[Michael Moroney]

phil-news-nospam@ipal.net writes:

One house I used to live in had 1 transformer to itself because it was
an add-on to a development that wasn't originally planned. I've also
seen as many as 12 houses run from 1 transformer and it wasn't very big,
either (looked to be 75 to 100 kVA at most). But if those houses had
60 amp service, it could work.

The most I know of is my father's summer cottage, where there were 13
cottages on a single transformer (I say were because one winter the top of
the pole the transformer was on broke off and energized the secondary with
7200 volts and two of the places burned to the ground, and one was not
rebuilt. Another was demolished later) They all had 60A service when
built in the 30s or 40s though many have 100-200A now. My father's place
is two poles away and has noticeable light blink. The new transformer
isn't very big (it either has 50 or 37+ stenciled on it).
--
-Mike

 

[John Woodgate]

I read in sci.electronics.design that phil-news-nospam@ipal.net wrote
(in <ch1hbq226nh@news2.newsguy.com&gt about 'Laser printer draws current
in a spike, what for?', on Tue, 31 Aug 2004:

I've also
seen as many as 12 houses run from 1 transformer and it wasn't very big,
either (looked to be 75 to 100 kVA at most). But if those houses had 60
amp service, it could work.

Experience shows that there is a huge allowance that can be made for
diversity. The average consumption of a UK house is 1 kW. I believe it's
3 kW in USA. You can tell from your bills. So 12 houses at 3 kW is 36
kW. A 75 kVA transformer would be quite OK, unless some exceptional
condition arose. I have put on 7 kW of fan heaters in my house when I
returned to find that the boiler was not working. If everybody did
that....
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Jim Thompson]

On Tue, 31 Aug 2004 22:59:37 +0100, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that phil-news-nospam@ipal.net wrote
(in <ch1hbq226nh@news2.newsguy.com&gt about 'Laser printer draws current
in a spike, what for?', on Tue, 31 Aug 2004:

I've also
seen as many as 12 houses run from 1 transformer and it wasn't very big,
either (looked to be 75 to 100 kVA at most). But if those houses had 60
amp service, it could work.

Experience shows that there is a huge allowance that can be made for
diversity. The average consumption of a UK house is 1 kW. I believe it's
3 kW in USA. You can tell from your bills. So 12 houses at 3 kW is 36
kW. A 75 kVA transformer would be quite OK, unless some exceptional
condition arose. I have put on 7 kW of fan heaters in my house when I
returned to find that the boiler was not working. If everybody did
that....

My monthly average for July was 8.1kW, so I probably had peaks 2X-3X
as much.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Louis Bybee]

<phil-news-nospam@ipal.net> wrote in message
news:ch1hjr326nh@news2.newsguy.com...

In alt.engineering.electrical Louis Bybee
louistroutbybee@comcasttrout.net> wrote:

| 210.6(A) applies to dwelling and guest rooms of hotels, motels, etc.
This
| article wouldn't be applicable to homes, and office environments. It
also
| relates to voltage between conductors. Ground isn't referenced in
210.6(A).
|
| 210.6(A)(2) restricts to 1,440 va and below, or 12 amps at 120 volts
again
| in dwelling and guest rooms of hotels, motels, etc.

Homes are considered dwellings.

If you reread 210.6(A) and observe the puncuation you'll see that it refers
to <dwelling AND guest> rooms of <hotels,motels, etc.>

Check with your AHJ, but most localaties will enforce the article with that
understanding.

| Most 240 volt circuits, in areas of the USA that I'm familiar with, are
120
| volts with respect to ground with the exception of the wild leg of a 240
| volt 3 phase delta, with one leg center tapped to ground. In that case
the
| wild leg usually isn't present in panels designed for single phase
loads.

And most of the homes don't have the wild leg at all.

True, but I have encountered apartment, and other communal structures with a
240 Delta one leg center tapped, service. Usually the wild leg will only be
present in panels for common area supporting equipment such as HVAC, pump,
and other large current drawing equipment.

But some places have 208Y/120, so no 240 at all, but it is 208.


| Never enough time or money to do it right the first time, but always
enough
| after the fact! :-]

It's called "wait for a disaster to happen".

With the atten you are paying to dietail I would enjoy seeing your final
electrical plans for your impending home. I suspect I would enjoy living in
it!

Louis--
*********************************************
Remove the two fish in address to respond

--
--------------------------------------------------------------------------
---
| Phil Howard KA9WGN | http://linuxhomepage.com/
http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/
http://ka9wgn.ham.org/ |
--------------------------------------------------------------------------
---

 

[John Woodgate]

I read in sci.electronics.design that Jim Thompson
<thegreatone@example.com> wrote (in <vku9j09163udbim9ij740h67ru4243ob22@
4ax.com&gt about 'Laser printer draws current in a spike, what for?', on
Tue, 31 Aug 2004:

My monthly average for July was 8.1kW, so I probably had peaks 2X-3X as
much.

Mostly for egg-nishners?
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

In alt.engineering.electrical Louis Bybee <louistroutbybee@comcasttrout.net> wrote:

| If you reread 210.6(A) and observe the puncuation you'll see that it refers
| to <dwelling AND guest> rooms of <hotels,motels, etc.>
|
| Check with your AHJ, but most localaties will enforce the article with that
| understanding.

The punctuation to construct that logic is not there. There is also a switch
between "and" and "or" which implies a separate context. Thus you have (my
addition of parenthesis):

In (dwelling units) and ((guest rooms or guest suites) of hotels, motels,
and similar occupancies), the voltage shall not exceed 120 volts nominal,
between conductors that supply the terminals of the following ...

I'd like to have your interpretation. But such an intent would not be written
as it has been. Instead, that would be written like:

<example not real NEC>
In dwelling units, guest rooms, or guest suites of hotels, motels, and
and similar occupancies, the voltage shall not exceed 120 volts nominal,
between conductors that supply the terminals of the following ...
</example not real NEC>

So if the intent was to narrow "dwelling units" to just those of hotels,
motels, and similar occupancies, it would be appropriately written as in
my example.

Still, I think I can get away with having extra 240 volt receptacles
around by merely having (or saying I will have) a portable appliance
that uses 1500 watts or more. A sealed oil heater I used to have in
fact had switchable 600 and 900 watt element and could run both at
the same time. But that ran on 120 volts. I only need to find me a
240 volt version (or hope they designed it with reconfigurable dual
elements for world markets).


| True, but I have encountered apartment, and other communal structures with a
| 240 Delta one leg center tapped, service. Usually the wild leg will only be
| present in panels for common area supporting equipment such as HVAC, pump,
| and other large current drawing equipment.

Still, all the single phase loads are running off one of the phases.

And utilities are phasing out delta apparently due to problems with it
such as blowing fuses on feedback due to a single phase outage. Now
that could still be done with a Scott-T setup without the delta feedback
problem.


| With the atten you are paying to dietail I would enjoy seeing your final
| electrical plans for your impending home. I suspect I would enjoy living in
| it!

Split level A-frame with beam construction and almost all solid wood
paneling walls and solid wood floors at 45 degree angles. Each bedroom
has its own bath and a balcony.

I am working on a program to convert a text-like construction language
into floor plan graphics and will be designing it that way, eventually.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

[Louis Bybee]

<phil-news-nospam@ipal.net> wrote in message
news:ch41p50o2f@news4.newsguy.com...

In alt.engineering.electrical Louis Bybee
louistroutbybee@comcasttrout.net> wrote:

| If you reread 210.6(A) and observe the puncuation you'll see that it
refers
| to <dwelling AND guest> rooms of <hotels,motels, etc.
|
| Check with your AHJ, but most localaties will enforce the article with
that
| understanding.

The punctuation to construct that logic is not there.

I suspect that you have software programming experience? It appears that you
are taking a Bolean approach to the text?


There is also a switch

between "and" and "or" which implies a separate context. Thus you have
(my
addition of parenthesis):

In (dwelling units) and ((guest rooms or guest suites) of hotels,
motels,
and similar occupancies), the voltage shall not exceed 120 volts
nominal,
between conductors that supply the terminals of the following ...

I'd like to have your interpretation. But such an intent would not be
written
as it has been. Instead, that would be written like:

example not real NEC
In dwelling units, guest rooms, or guest suites of hotels, motels, and
and similar occupancies, the voltage shall not exceed 120 volts nominal,
between conductors that supply the terminals of the following ...
/example not real NEC

So if the intent was to narrow "dwelling units" to just those of hotels,
motels, and similar occupancies, it would be appropriately written as in
my example.

I believe you've identified the problem! It's your phrase "appropriately
written". At best the NEC is a convoluted exercise enough to render the
possibility of much of it being unmistakeibly clearly written as to avoid
misunderstandings very unlikely. :-]

Every AHJ I've experienced considers 210.6(A) to solely apply to transient
forms of accomodation, and not private residential/apartment housing. If
incorrect there are numerous small air conditioners, and other small
appliances in homes that are in danger of non-compliance. :-]

Rather than take my, or anyone elses word on the subject consult your local
AHJ. Most AHJ will be very accomodating, and helpful when it's clear your
interested in an opinion to assist you in being in compliance with national,
and local codes.

Louis*********************************************
Remove the two fish in address to respond

Still, I think I can get away with having extra 240 volt receptacles
around by merely having (or saying I will have) a portable appliance
that uses 1500 watts or more. A sealed oil heater I used to have in
fact had switchable 600 and 900 watt element and could run both at
the same time. But that ran on 120 volts. I only need to find me a
240 volt version (or hope they designed it with reconfigurable dual
elements for world markets).


| True, but I have encountered apartment, and other communal structures
with a
| 240 Delta one leg center tapped, service. Usually the wild leg will only
be
| present in panels for common area supporting equipment such as HVAC,
pump,
| and other large current drawing equipment.

Still, all the single phase loads are running off one of the phases.

And utilities are phasing out delta apparently due to problems with it
such as blowing fuses on feedback due to a single phase outage. Now
that could still be done with a Scott-T setup without the delta feedback
problem.


| With the atten you are paying to detail I would enjoy seeing your final
| electrical plans for your impending home. I suspect I would enjoy living
in
| it!

Split level A-frame with beam construction and almost all solid wood
paneling walls and solid wood floors at 45 degree angles. Each bedroom
has its own bath and a balcony.

I am working on a program to convert a text-like construction language
into floor plan graphics and will be designing it that way, eventually.

--
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---
| Phil Howard KA9WGN | http://linuxhomepage.com/
http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/
http://ka9wgn.ham.org/ |
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---

 

phil-news-nospam@ipal.net wrote:

In alt.engineering.electrical Andrew Gabriel <andrew@cucumber.demon.co.uk> wrote:

| In article <MMyWVDBvauMBFw+u@jmwa.demon.co.uk>,
| John Woodgate <jmw@jmwa.demon.contraspam.yuk> writes:
|> According to US sources, problems such as you report never occur, and
|> they don't need to implement the IEC versions of those ENs as US
|> standards. So you are actually just imagining the flicker. (;-)
|
| The irony is this is quite common in the US, but I've never seen
| it happening in a 240V country ;-)

We do have 240 volts. The problem is that we also have the NFPA that
publishes the NEC which in 210.6(A)(2) restricts the voltage for cord
and plug equipment to a maximum of 120 volts relative to ground, thus
disallowing the use of the 240 volt connection for the typical laser
printer.

I don't get your point. Our (US) 240 volt circuits are

120 volts relative to ground. I've got a 240 volt
cord and plug connected air conditioner. NFPA
does not prohibit 240 volt appliances, so I'm
missing your point.

In any event, you don't need a 240 volt circuit
to solve the problem of dimming lights when the
laser printer fuser heats. Put the printer on a
separate circuit. Essentially, that is what putting
it on a 240 volt circuit would do anyway, so
the fact that it draws less current on 240 wouldn't
matter.

 

In alt.engineering.electrical Louis Bybee <louistroutbybee@comcasttrout.net> wrote:

| I suspect that you have software programming experience? It appears that you
| are taking a Bolean approach to the text?

Only to analyze, not to interpret. Interpretation is being made by
proper grammatical usage. I double check that by reversing the process
and determining how to say various possible intentions and seeing what
matches up.


| I believe you've identified the problem! It's your phrase "appropriately
| written". At best the NEC is a convoluted exercise enough to render the
| possibility of much of it being unmistakeibly clearly written as to avoid
| misunderstandings very unlikely. :-]

And to the extent that is true (and it very well may be, given many other
examples), that means no intrepretation is reliable.


| Every AHJ I've experienced considers 210.6(A) to solely apply to transient
| forms of accomodation, and not private residential/apartment housing. If
| incorrect there are numerous small air conditioners, and other small
| appliances in homes that are in danger of non-compliance. :-]

I've not seen a small air conditioner that violates it. Everything below
1440 watts is 120 volts.


| Rather than take my, or anyone elses word on the subject consult your local
| AHJ. Most AHJ will be very accomodating, and helpful when it's clear your
| interested in an opinion to assist you in being in compliance with national,
| and local codes.

What I need is something broader than one one AHJ will interpret it as.

I'd love to see it interpreted as the transient dwelling meaning. But if
some AHJ didn't interpret it that way, I find no method to argue that such
an interpretation is wrong.

Well, either way, that rules out a hotel in the US providing world voltage
compatibility outlets for their foreign guests. Gotta use those step-up
transformers.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------