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?.

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


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


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 If so, that is outdated by 30-40 yrs.


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).]

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.

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?.

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?.

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.



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

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

Hehe, that's a good one, Virgil!.

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! )

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.

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!

But you savor the meal more if you take your time!

Hutch mentioned keeping the fork in the left hand all the time (assuming a right-handed person), but the other quirky habit that even as a Brit I can never understand is trying to pile food on a fork that's upside down!

Many Brits will hold the fork (in their left hand) with the convex surface uppermost. They stab a piece of meat on the end of the fork, and then still keeping it upside down use the knife to pile potato, bits of vegetable, and anything else from the plate on top. There then comes a kind of balancing act to transfer this volcano-shaped load from plate to mouth without spilling any!

Talk about making things difficult for yourself!

Some places, namely more urban utilities, rented electric water heaters that are genuine flat rate (my grandmother's was).

In the town my brother lives in there are a number of single family houses with two meters, one for normal electical useage, the other specifically for heating (I don't think water, just radiant).

PS: Rumour has it that our utility (Hydro One in Ontario, Canada), is going to switch to dual rate meters.

[This message has been edited by classicsat (edited 08-25-2004).]

We have a similar system in Britain which has gone under the name of "Economy 7" for many years.

The way it's done these days is to use a meter with dual-dials and a separate control connection (all electronic on the modern digital meters, but on older mechanical dials it actually operates a tiny solenoid to change the linkage).

There's then either a PoCo-owned timeswitch or a remote-controlled (telemetry) switch which changes the meter to the lower rate at night, generally midnight to 7 a.m. in winter, 1 a.m. to 8 a.m. in summer (i.e. 7 hours of cheap-rate, hence the Economy 7 name).

A contactor is also energized during the 7-hour period to apply power to a separate distribution panel which feeds storage heaters. The heaters are thus charged automatically at night, but the whole house benefits from the lower rate as well.

Night rate is typically around half of the normal day rate. At the moment I'm paying 6.75 pence per kW/h day and 2.87p. per unit night (plus tax).

An older variant of this system did actually use two separate meters, and was commonly known as "White meter" for the color of the cheap-rate meter. This had the same timeswitch/contactor arrangement to charge storage heaters at night, but the main distribution panel remained on the normal tariff all the time.

Trumpy,
I was a little confused when i saw the date on this thread, however, it became clear when I saw your reply which was made with the benifit of hindsight. Quite apart from remonstrating with yourself about making assumptions, it is clear that you have a passion for the trade and an associated thirst for more information. It is something that I share and by the looks of it, it is endemic in this forum. Unfortunately, it seems to be the preserve of only a minority of those involved in the electro-technical sector. Perhaps most people are sparks just for the job rather than for some vocational reason.