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49-1
1
Mozambique
(50)
220/380
Niger
(50)
220/380
Nigeria
(50)
230/400
Senegal
(50)
127/220
Sierra Leone
(50)
230/400
Somalia
(50)
220/440;
also
110,
230
South Africa
(50)
2201380;
also
others, some dc
Sudan
(50)
240/415
Tanzania
(50)
230/400
Tunisia
(50)
2201380;
also others
Uganda
(50)
240/415
Zaire
(50)
220/380
Zimbabwe
(50)
220/380;
also
230/400
Oceania:
Australia
(50)
240/415;
also
others and dc
Fiji Islands
(50)
240/415
Hawaii
(60) 120/240
New Caledonia
(50)
220/440
New Zealand
(50)
230/400
Notes:
boards, based in the. USA primarily
on
the National
Electrical Code (NEC)* and the National Electric
Safety Codes.? Brief extracts from some NEC require-
ments are given here for convenient reference.
Many products such as wire and cable, fuses, outlet
boxes, appliances, etc., are governed within the USA by
Underwriters Laboratories (UL) Standards, which
specify the terminology used for the various classes
of
an item as well as the safety requirements that must be
met by UL approved items. Note that the overall
performance of assemblies such as appliances, motors,
radio equipment, or television equipment is not covered
by NEC or UL standards, which are primarily for
personnel safety.
The following tables
are
provided.
Tables
5
and
6:
NEC standard types of insulated
Tables
7
and
8:
Allowable currents for conductors.
Table
8:
Derating factors to be applied for ambient
temperatures above
30
"C
(86
OF) and for more than
three conductors in a cable or conduit.
Table
9:
Motor starting currents, which det.ermine the
wires and cables.
-
Abstracted from
Electric Power Abroad,
issued
1963
by the Bureau of International Commerce of
the US Department of Commerce. This pamphlet
is obtainable from the Superintendent of Docu-
ments,
US
Government Printing Office, Washing-
overcurrent protection requirements during the starting
period.
Table
10:
Motor full-load operating currents for
usual
conditions and speeds.
ton, D.c.
20402.
The listings show electric (residential) power
I
.,
Guide
to
Use
Of
Tables
Determine the total equipment load by adding the
supplied in each country; as indicated, in very
many
Other
types
Of
exist
to
a
loads of the various individual items, estimating motor
currents according to Table
10
if specific operating-
greater or lesser extent. Therefore, for specific
characteristics
Of
the
power
Of
current information is not otherwise available. Any load
cities, reference should be made to
Electric Power
bigger
than
this
should
be intempted
by
standard fuse or circuit breaker is considered satisfac-
tails such as number of phases, number
of
wires to
the residence, frequency stability, grounding reg-
+n...r
This
pamphlet gives
de-
an
overload protective device; the n&-larger
ulations, and some data
on
types of commercial
service.
,
In
the United States in urban areas, the usual
supply
is
60-hertz 3-phase
120/208
volts; in less
densely populated areas, it is usually
1201240
volts, single phase, to each customer. Any other
supplies, including dc, are rare and
are.
becoming
more
so.
Additional information for the
US
is
given in the current edition of
Directory
of
Elec-
tric Utilities,
published by McGraw-Hill
Book
Co.,
New York,
N.Y.
4.
All voltages in the table are ac except where
specifically stated as dc. The latter are infrequent
and in most cases are being replaced by ac. The
lower voltages shown for ac, wye or delta ac, or
for dc distribution lines, are used mostly for
lighting and small appliances; the higher voltages
are used for larger appliances.
ru1y.
Determine the total starting load by using the locked-
rotor currents computed from Table
9
and the steady-
state currents for resistive devices. Make an additional
allowance for
any
large quantities of tungsten lamps,
starting transients, and high-inertia loads that will
increase the duration of the starting period. The circuit
overload protection must be designed to
carry
this load
for the entire starting period. Time-lag fuses or time-
delay circuit breakers are usually desirable.
Using the starting currents, determine the voltage
drops in the supply circuit; thus be sure that the terminal
voltage
of
the motor or other device will be adequate at
start.
Increase the size
of
the supply conductor or
reduce the source impedance if necessary. From the
starting and running currents, determine the required
size of supply conductors.
*
American National Standards Institute, Inc.,
ANSI
Standard
C1,
prepared
by
the National Fire Protection
Association.
POWER SUPPLY WIRING
Electric power supply (mains) wiring is usually
controlled for public safety by local or state government
f
ANSI
Standard
C2.