On Sun, 27 Dec 2009 03:24:59 GMT, email@example.com (Doug Miller)
Well, I monitor the voltage on my home office power as well as at a
customer site and it is very consistent at 115-117 volts at both
sites. Has been for years. This is in urban Waterloo Ontario and
Also virtually every motor or electrical device sold in North America
for residential use is rated at 115 or 230 volts.
In industrial and large multi unit residential applications with 3
phase power it is 120/208. Virtually everywhere else in Ontario, at
least, it is 115/230 single phase.
BC Hydro specifies voltage to be within the limits of 110 to 125
volts. That is a range of 15 volts, with a center "target" voltage of
FWIW, as I sit here in Austin, Texas, the power line monitor in front of
me indicates that we're getting 122.8 volts from the local utility.
When it's hot (i.e. when the air conditioning load is high) that can
drop quite a bit. I think a nominal 117.5 is pretty close to right
for the median.
And right now, Sunday afternoon of a mild "holiday" weekend with no
industrial power usage, and very little heating requirement (compared
to average for this time of year) my power in Waterloo Ontario is
sitting at a relatively high 117.6 volts RMS
And what comes into your house must there be the standard. :-)
A quick random sample of half a dozen of my portable power tools and kitchen
appliances shows five marked "120V" and one marked "120V only". In fact, the
only thing I could find in the house that's marked for 115 is an electric
clock that to my certain knowledge is _at least_ forty years old.
On Dec 27, 10:37 am, firstname.lastname@example.org (Doug Miller) wrote:
What are the USA and Canadian limits for voltage variation from a
nominal of say 117 volts?
Using 117v as a base;
Minus 5% = 111.15 (say 112v RMS)
Plus 10% = 128.70 (say 129v RMS)
And as mentioned in some installations the higher voltage can be
either 230/115 volt (Usually domestically) or 208/115 (most likely
commercially and/or from 3 phase supply).
We have electric baseboard heaters that came, marked; 1200 watts at
230 volts, 970 watts at 208 volts. (The V squared divided by R = W
BTW. Further to this discussion about higher mains supply voltages and
permissible limits for variations these days; the topic has come up
often in another news group that deals with vintage radio restoration
The more consistently higher voltages these days can have an impact on
older radios that were operated back when on, say 115 volts or less.
But which today often face 120 or higher.
Again (for simplicity) doing the V squared business, the difference
between say 113 volts and say 120 volts is almost a 13% increase (plus
one sixth!) in power and therefore additional heat within an old
The radio restorers therefore use their expertise and various means to
either further protect (extra fuses etc) and/or to reduce voltage to
protect the older equipment components.
On Sun, 27 Dec 2009 19:07:49 GMT, email@example.com (Doug Miller)
An increase of 6.19% in voltage from 113 is 120 vots, but the
increase in POWER would be at least 13% because the resistance stays
the same, so when the voltage goes up, the current also goes up, and
the power is the product of the two.
On Dec 27, 4:29 pm, firstname.lastname@example.org wrote:
Yes; accept the correction. It's a VOLTAGE increase (difference) of
Making the assumption that the resistance (or AC impedance) remains
the same the WATTAGE will increase by approx. 13%. That should have
been fairly obvious?
But the way one often explains it to the technically challenged is to
first ask; "If the voltage was say 120 volts and is then doubled to
240 volts, how much more CURRENT will flow (assuming all other circuit
components remain unchanged)?
The answer is obviously "Twice as much". One then says '' Well with
twice the voltage and twice the current there will be four times power
(wattage). Right?". (2 times volts) x (2 times amps) = 4 times volt-
That usually gets them thinking and it's then possible to explain the
simple math derivation from Ohm's law that Voltage squared divided by
Resistance = Power (wattage).
And suggest then; so what would happen if the voltage increased by say
ten percent? The answer is about 20%. i.e. 1.1 x 1.1 = 1.21 (i.e.
Twenty one per-cent power increase)!
But I've met electricians who can wire a dream but must understand
basic electircity in a manner different to one's own!
On Sun, 27 Dec 2009 13:37:09 GMT, email@example.com (Doug Miller)
My US built 4 year old Tempstar furnace says for 115 volts AC
operation.. One of my (2 way) radio power supplies says 117 volt AC
My compressor motor says 115/230 volts AC. (it is a year old).
My Beam central vaccum says 115 volts.
My stereo pre-amp says 117 volts AC.
Heck, my model train transformer says 117 volts. Then most of my
computer stuff says 84 - 240 volts AC or 100-240 VAC.
My experience is that 20 years ago, average voltage around here was
much higher than it is today. 117 was low, and 123 was not uncommon.
For the last 5-10 years if I see 120, it is high. 117 is common, and
as low as 114 is certainly not unheard of.
My central air unit says 230 VAC.
I've always looked at the disparate voltage ratings on the various
pieces of equipment I've stumbled across in my lifetime to be the
reference point for the current and wattage specifications. There
has to be a reference point if that makes any sense to you. "This
is a 500 watt widget." "Oh yea, at what voltage?" When I look at a
piece of gear and see the voltage/wattage spec, I always know for
sure without any calculation if the facilities are going to be able
to power it. The stuff adds up, since I've done a lot of primary
and backup generator work, I automatically think of surge and motor
start loads also. So many times I have to argue with someone who
wants to plug in 3 refrigerators and 2 freezers on the same circuit
because the nameplates show 3 amps. ARGGGGG!
But its that funny Canadian stuff.
The explanation I have heard is 120/240V is the nominal supply voltage
(at the service). And 115/230V is the nominal voltage at equipment
(after voltage drop). (Would be interesting where 117V comes from.)
The NEC says to use 120/240 for calculations. The values for current in
the NEC motor tables are for 115/230V.
IMHO arguments about what is "correct" are useless.
The US Grid (PSC etc) say it's 120/240 +- 5% and 60 Hz nominal over, I
think, 24 hours. THOSE are the specs used transformers outputs. Not in that
range? There is a problem or you're in a brownout/overvoltage mode at the
grid. The misnomers come from a time when different areas of the country
actually did have various nominal voltages such as 115, 117, 120, etc.
I've heard 110, 115, 117, 118, 120, and 125 for one side. What I
measure here is almost exactly 120 (it drops as low as 118 sometimes).
I seem to remember reading it was 100 at one time.
Older people often say 110 and 220. I will when I'm talking to them,
otherwise I sway 120 and 240.
Oh yeah? And I suppose you totally ignore your local ordinances, don't you?
I have to wonder if you didn't get dinged for it, too since you consider it
such a great, wonderful thing and assumed on your own that it's what the OP
had. You become more of a dunce with every post I see of yours. You're a
real troll, I guess.
Nonsense is right; it's extremely easy to misinstall something; I've seen it
time after time and luckily always caught it but - it's amazing the kinds of
mistakes even electricians can make. They work drunk, hung over and worse
sometimes, especially in Chgo when we lived there. I had one inspector out
to get one guy fired at one install. Hmm, that wasn't you, was it?
I never said that wasn't so. People commonly refer to several different
numbers they see on their equipment. You're a myopic egotist from the look
of it; you post just to see yourself in writing.
See, there's your assumptions again, and stated as a fact this time, which
makes it a lie. So now you're a liar, on top of everything else. You're
getting to be fun.
No, it's not false; you are seriously misinformed of the dangers of such
circuits. This is an exposure of an ignorance that plummets your credibility
even further than it has been. Such a ckt could only ever be "safe" if it
could never develop a fault; which it can, on top of miswiring and other
possibilities you'd know if you actually knew much about it. Knowing a buzz
word doesn't make you an expert in any way. Look it up.
And that has nothing to do with national vs. local codes.
Until a fault arises. Neutral pops off a stressed outlet with a poor
mechanical connect, improperly protected by a ganged breaker, etc. etc.
etc.. It's much more dangerous than other ckts given even the same faults
in many instances. Your ignorance must really be bliss. ALL of the
following make perfect sense and come from the first page of google hits.
Audiophiles just abhor them!
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