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#133258 07/13/02 11:16 PM
Joined: Jul 2002
Posts: 8,412
Likes: 3
Trumpy Offline OP
Member
I have a number of questions regarding the
wiring systems used in the US.
1) Do the commercial/industrial installations
use a 3-phase system, similar to the 230/400V
MEN system here in New Zealand?.
2)How is an installation earthed in the US?,
wether this be a domestic,commercial or
industrial type installation.
3)Why are internal circuits in US houses,
run in metallic flexible?.
4)Why do US socket outlets not have in-built
switches?.

#133259 07/14/02 05:15 AM
Joined: Oct 2000
Posts: 5,389
S
Member
Quote
1) Do the commercial/industrial installations
use a 3-phase system, similar to the 230/400V
MEN system here in New Zealand?.

3ph 4 wire wye, or 3ph 3 wire delta's

Quote
2)How is an installation earthed in the US?,
wether this be a domestic,commercial or
industrial type installation.

It is not 'single point'. there is an x-former N to G earthing, as well as a premisis N to G earthing done. Not an optimum design IMO

Quote
3)Why are internal circuits in US houses,
run in metallic flexible?.

more are in romex, are you refering to the old mettalic BX here? If so, that is outdated by 30-40 yrs.


Quote
4)Why do US socket outlets not have in-built
switches?.
or fuses, or childproof covers, etc. There are 'safer' options. However , safety here is a business, evolving via body count more than anything else.......

[This message has been edited by sparky (edited 07-14-2002).]

#133260 07/14/02 07:00 AM
Joined: Aug 2001
Posts: 7,520
P
Member
Hello Trumpy, and welcome to ECN!

American wye/star commercial systems are commonly 120/208V or 277/480V. They also have 240V and 480V delta supplies.

One strange system (from a non-American's point of view) is the 4-wire delta with high-leg. It's basically a 240V delta system but with the mid-point of one winding earthed. The arrangement allows for connection of 120V equipment on two of the phases, but the third phase ends up at 208V to ground. Nothing like it in this part of the world.

On grounding/earthing arrangement, the U.S. bonds the installation earth to the incoming neutral, like the your MEN system or the British equivalent, PME. They don't earth to just a local rod as is done in some parts of the world.

Re switched outlets, it seems to be mostly British-influenced countries that use them, such as Ireland, Australia, parts of Africa, etc. They're not common in the Americas or in Continental Europe either.

#133261 09/14/02 01:05 AM
Joined: Jul 2002
Posts: 8,412
Likes: 3
Trumpy Offline OP
Member
Why do you guys use single wires with
your service intakes or are they actually
the ends of a Neutral-screened cable, that
you cannot see the sheathing on?.

#133262 09/24/02 02:41 AM
Joined: Jul 2002
Posts: 8,412
Likes: 3
Trumpy Offline OP
Member
What type of fusing/circuit-breakers are being used in America, these days, for domestic installations?.
Also, are electric ranges(cookers), still fed with 2-Phase 230V?.
Do you guys use any form of Ripple control over there( ripple control is where the power
company uses a frequency-controlled relay, to energise/de-energise certain loads,
normally, hot water cylinders, Nightstore heaters.
Just curious?. [Linked Image]

#133263 09/24/02 02:50 PM
Joined: Nov 2000
Posts: 2,236
Member
Thermal-Magnetic Circuit Breakers are the norm here... I've never even heard of a "new" residential fusebox. I guess, with our materialism and hedonism, fuses would be very inconvenient...

Dryers and Ranges are all generally 120/240V. Water Heaters are usually straight 240V. (Not really 2 phase, but opposite poles of the same phase, if that makes sense...)

Here, back in the late 40's early 50's, the power company supplied two meter bases. One was for your lighting and power circuits for your home, the other was for just the water heater at a reduced rate. Apparently the PoCo wanted to compete with Natural Gas.

Allegheny Power owns both the electric and gas reserves here... So no competition exists anymore.

[Linked Image]

The guys in California would be more likely to have seen the exotic environ"mental" stuff!

[Linked Image]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
#133264 08/21/04 06:04 PM
Joined: Jul 2002
Posts: 8,412
Likes: 3
Trumpy Offline OP
Member
Quote
Do you guys use any form of Ripple control over there( ripple control is where the power
company uses a frequency-controlled relay, to energise/de-energise certain loads,
normally, hot water cylinders, Nightstore heaters.

Man,
That was a BIG assumption back then!.
That everybody else uses the same system as me!

Quote
The guys in California would be more likely to have seen the exotic environ"mental" stuff!
Hehe, that's a good one, Virgil!. [Linked Image]

#133265 08/22/04 05:06 AM
Joined: Aug 2001
Posts: 7,520
P
Member
It's all to easy to make assumptions about the way things are done elsewhere if you've grown up only ever knowing one way, be it electrical methods, road signs, or even the way you hold your knife and fork!

(I mention that last one as I fell into the "American method" of eating years ago and still sometimes find people giving me strange looks here! [Linked Image])

#133266 08/22/04 09:28 AM
Joined: Sep 2003
Posts: 123
M
Member
The delta with the high leg is sometimes called "wild leg", the high leg is supposed to be a different color. If it's not (common practice) it can be very hard on 120V equipment. Another little oddity we have here are shared neutrals. Where all phases of a 120 panel share the same neutral. Obviously there can be sizing issues, but the real fun can be if someone disconnects the neutral and the circuit becomes 240V.

BTW, Knife and Fork? I have heard about not putting them down, but one hand is for which one and not the other??

You realize of course, the only reason we do things backwards is so we can tell who the Tories are. [Linked Image] [Linked Image] [Linked Image]

#133267 08/22/04 10:34 AM
Joined: May 2002
Posts: 381
H
Member
As British imports in to this fair American land we bring along a few of our quirky habits amongst which are our use of weapons at the table. It’s not so much putting them down (which we do occasionally) it is that having put one’s dagger in one’s right hand to slice the object held by the fork in the left we don’t ever switch them around again.

We are the object of local amusement in restaurants and at company Christmas dinners but we have noticed that we eat at approximately twice the pace of our hosts. All that tedious swapping around of ironware take a lot of time you know! [Linked Image]

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