Don Pearce wrote:

On Fri, 3 Feb 2012 08:38:19 -0500, "Arny Krueger"
wrote:


"David Looser" wrote in message
...
"Arny Krueger" wrote

Seems like a lot of wiring and separate little boxes to handle not so
many circuits.

I presume that it provides service for more than just one little hotel
room.
Yes, that's the main incoming supply to the building. The grey unit at the
bottom left is the supply company's terminating unit that inludes their
fuses. Above that is the meter, to the right of it is a neutral block, and
beyond that an isolator (looks like a three-phase + neutral one). I'm not
sure what the unit above the isolator is, but at the top of the wardrobe
are three consumer units, each, apparently, fed from a different phase.
The one on the right seems to feed just one, high-current, load.

In the US even fairly large homes and retail stores generally have just two
boxes - a meter box and a distribution panel box. 120 volt and 240 volt
circuits are distributed from there.

There are exceptions. For historical reasons, my ca. 1933 home has 2
subpanels and should have 3. It also has a safety switch in a separate box
outside by the meter because the run to the main distribution panel in the
basement is so long. This place is really gerrymandered as its needs
increased dramatically over the years.

Intermediate-size buildings such as a large factory, apartment building or
superstore have a central meter and a few large breakers in just two boxes,
and additional subpanels as needed.

Really large buildings distribute HV (e.g. 4,800 volts) inside the building
and have transformer substations in various locations. The metering is
generally still centralized.

If there are multiple paying accounts within a building there will be
multiple meters and each has its own distribution infrastructure.


Do the 120V and 240V system share the same high voltage distribution
lines? I mean is the transformation done per house, per street or per
district? It just strikes me that with 240V available the requirement
for 120V should be dwindling. It really is too low for even
distribution within a house. I have experienced lights dimming
significantly when appliances are turned on in many American homes.


Then it needed to be inspected and repaired. That is a common symptom
of an open neutral, or one that is failing.


--
You can't have a sense of humor, if you have no sense.