phil-news- said:
| Could be. They are the same lug in the entrance panel. I guess
| you can call it a neutral, since it is carrying current. ;-) It's
| bonded to the case though. ...as my MIL found out.
An entrance panel might do that.
Entrance panels *DO* do that. The ground and neutral are bonded
in the entrance panel. In this particular case the *RED* wire
was connected to the ground-strap and the white was hooked to the
hot. exciting when you touched the drier case! I found out jut
how exciting when I hooked a ground strap to the cold water pipe,
an zapped a 60A fuse.
But there should be separate neutral and
ground bus bars, just connected together in the entrance panel and kept
separate in subpanels.
Not necessary. In the entrance panel they can all be wired
together. Certainly in a sub-panel they're separated (I just had
to separate them in her house so we could sell it).
|> Are you talking about a NEMA 6-30R or a NEMA 10-30R? I'm talking about
|> the 10-30R.
|
| Not sure. I've only seen the thing twice (when I bought it and
| when I moved).
Grab this file and view the dimensions:
http://www.nema.org/DocUploads/569F336F-E550-4BD8-935019C2E658D5A0/WD6w.pdf
I can do that, but I'm not about to pull our laundry room apart
to measure. ;-)
| I didn't say you did. My point was that a 240V motor, given the
| volume of driers sold, shouldn't be any more expensive than a
| 120V motor. I have no clue why they use a 120V motor. Seems
| pretty stupid to me, but there must be a reason.
A motor can be made cheaper if it's windings are at a fixed voltage and
there is no option to rewire to a higher voltage, as would be the case if
the windings were paired with 4 leads each.
IIRC 600V wiring is required for all residential circuits. I
thought this was true for appliances too, but I could be wrong.
I'm not a power expert, as you've noted.
Since instead of a versatile
motor, you have to make separate ones for each voltage. Given the massive
market scale for 120 volt versions (for whatever reason, but perhaps due
to it being used for other appliances, too), the 240 volt version will
cost more because of the higher cost to inventory compared to sales
volume. Even if a single voltage motor over a dual voltage one saves
only $0.25, manufacturers will do such things.
I don't buy that argument. The gas/electric argument seems to be
better, but even that falls short. Motors wound for both are
ubiquitous. It's not rocket-surgery to have motors strapped for
whatever voltage.
|> Almost nothing needs a particular voltage. The need is for some
|> amount of power (real or reactive as the case may be). For things
|> as small as a bed lamp, alarm clock, or cell-phone charger, 240
|> volts offers virtually no advantage.
|
| Sure, my point is that most rooms have nothing in them that takes
| any significant power, so 120V is good enough. Kitchens,
| perhaps.
I'll still be putting a 6-20R or two in most rooms of my future house.
Maybe that's a good idea. Overkill, and you'll never get your
money back, but if that makes you happy... My father did the
equivalent sorts of things, though no one else cared.
The major room that won't have them is the bathroom (even though hair
driers pull a power level that really should use 240 volts).
I don't agree at all. Who needs more than a kW for a hair-
drier?! I'd rather *not* have 240V anywhere close to water. I
had 240V to my pool pump for the obvious reasons, but poolside
appliances ran off 120V. The 240V GFCI breakers were nutso too.
I have
seen countertop microwave ovens that use 240 volts, but never a hair
dryer. Usually they are wired on a dedicated circuit, and for the
planned one, it will get one. All the 6-20R's in the kitchen will be
GFCI protected at the subpanel adjacent to the kitchen, as will the
5-20R's. Both will have 120 volts to ground, which is the biggest risk
in a kitchen or other wet area.
....and you want 240V to the bathroom? My built-in
microwave/convection/range-hood is 120V. I know because I
replaced the thing a couple of years ago. No big issue there.
|> My suggestion for no neutral as a power configuration is more about
|> getting things on a singular standard voltage, and doing so in a
|> well balanced way, with a minimal ground potential. It's not that
|> things like bed lamp, alarm clock, or cell-phone charger need 240
|> volts, but rather, if they an everything else used 240 volts, then
|> the wiring would be simpler, and the ground potential would still
|> only be 120 volts (139 volts for three phase). In Europe, the 230
|> volt standard is between line and neutral/ground. So the ground
|> potential is the full amount.
|
| I don't see many appliances in the home that need higher power
| than can be delivered now at 120V. AC units, sure, but they
| usually have dedicated circuits. I have a small window unit, but
| it works fine off 120V too.
Sure, many things available that use 240 volts can also use 120 volts.
But I prefer to use them at 240 volts regardless. The only things that
I would be using at 120 volts are those that do not have any 240 volt
versions (which is most things).
I don't (prefer). I'd rather leave things at the lowest voltage
possible. 120V is just peachy for 90% of my uses. Dedicated
outlets (240V) work for the rest.
|> Eliminating the neutral leaves only one voltage, the line to line
|> voltage. Making the voltage higher means less current and even less
|> I^2*R losses in the wiring.
|
| Sure, but I don't see this as a significant issue in a
| residential dwelling.
We see things differently.
Obviously. The IR drop on most residential circuits is trivial,
IMO. My cell-phone charger isn't causing too much in the way of
global warming, the wires in the wall feeding it far less so.
| The advantage of the system as it stands is that I can use 120V
| for small things and glue two together for the biggies. That's
| about as simple as it gets.
But if the system had always been just 240 volt, would you really have
thought "Gee, if only I could have a current carrying conductor back to
the grounded center tap, I could run things on 120 volts, even though
I would now have double the current and no less risk of ground shock".
No, I wouldn't have had any such thought. I don't want 240V to
supply a tenth of an amp. There are so few places in my house I
need such huge power (and those have dedicated outlets) that I
see wiring 240V everywhere as a complication.
BTW, shared neutral wiring effectively gets you the same benefit of less
current for a given total (and balanced) load. Two 60 watt lights with
one on each pole of a shared neutral 3-wire circuit will draw a total of
0.5 amps, the same as a 120 watt 240 volt light would.
Obviously, but now I need both 120V and 240V lamps. No thanks.
Leave the trivial loads at 120V.
But to get that
advantage you also have to have the risk of a shared neutral circuit.
Huh? That's the whole point. We don't have any "shared-
neutral" loads. THe ones that are shared are designed to do so.
But that is a viable option with a 2-pole circuit breaker that ensures
both poles are cut off if either overloads. But I don't plan to do any
shared neutrals.
Of course. Why are you bringing in this strawman??
THe system works remarkably well, and has for many years. Many
smart people have done much to make it safe. I'm not about to
throw out all that's been learned over the last century and do
something different because I *THINK* I know better. I'll trust
the NEC, thanks.
.
