ELECTRICAL SERVICE RULE BOOK BULLETIN
NUMBER:
DATE:
EFFECTIVE UNTIL:
ORIGINATED:
INDIVIDUALS AFFECTED:
SUBJECT:
01
November 30, 2006
Rescinded
Electrical Standards
Internal and External Customers
Adjustable Breakers with Self-Contained MeterSockets
INTRODUCTION
Starting with this revision, the Electric Service Information (ESI) Manual will be changed to the
Electric Service Rule (ESR) Book.
Section 114. C. of the former ESI Manual limits the over-current protection for a self-contained
meter-socket to no more that the maximum rating of the meter-socket.
Section 114 states that the combined service or current protection rating shall not exceed
the ampacity rating of the self-contained meter socket. Self contained metering is
limited to a maximum of 300 amps capacity.
THE PROBLEM
Some electrical contractors have been using adjustable 400 ampere breakers, dialed down to
320 amperes, with 320 ampere self-contained meter-sockets. This is prohibited by the ESI
Manual, as stated above. Some individuals are incorrectly assuming that if a specific
installation is not addressed by the ESI Manual, then is should be allowed. It is impossible to
specifically cover every conceivable service option available in the ESI Manual. It may be
necessary to contact Alliant Energy personnel for clarification on those variations for which there
is a question
THE SOLUTION
In an attempt to clarify this specific issue, Section 114. C. of the ESI Manual is hereby modified
to read as follows:
The combined service or current protection rating shall not exceed the ampacity rating of the
self-contained meter socket. Self contained metering is limited to 300 amps capacity and
adjustable breakers, whose maximum rating either individually or in combination, exceeds the
rating of the self-contained meter-socket, are prohibited.
Alliant Energy will not allow any combination of Fuses or Breakers to be greater than the rating
of the meter-socket. For a two-hundred ampere self-contained meter-socket, a single fuse or
a single breaker, rated 200 amperes maximum, is allowed. For a three-hundred twenty ampere
self-contained meter-socket, either a 100 & 200 or two 150 ampere Fuses or some
combination of breaker/s, with a maximum rating of 300 amperes, is allowed.
QUESTIONS
Contact Rob Weber (319-786-4743) in Electrical Standards with any questions
concerning this bulletin.
Page 10
IP&L / WP&L
ELECTRIC SERVICE RULES
GENERAL INFORMATION
111.
Chapter 1
Issued 12 of 2006
INSPECTIONS AND MAINTENANCE
Alliant Energy reserves the right, but assumes no responsibility for inspection of the customer’s
installation.
112. SERVICE CONNECTIONS
Alliant Energy will make all service connections to its electric distribution system.
Connection to or alteration of the Alliant Energy’s electric service facilities or other
equipment is prohibited and is subject to immediate disconnection. Deviations from this
policy may be approved at the local office on an as needed basis.
113. IDENTIFICATION OF CONDUCTORS
A. The neutral or grounded conductor of a service entrance (480 V and under) shall be
identified by a white or gray color/ tape, or by three continuous white stripes on other
than green insulation along its entire length.
B. On 4-wire, delta connected secondary, where the midpoint of one phase winding is
grounded to supply lighting and similar loads, the phase conductor having the higher
voltage to ground shall be identified by an outer finish that is orange in color, by
tagging, or other effective means. Such identification shall be placed at each
location where a connection is made if the grounded conductor is also present.
114. CAPACITY
A. Service entrances shall have ample capacity, per The National Electrical Code, see
NEC Article 220, for any electrical load that may reasonably be expected to develop.
All current carrying components of the metering installation shall have an ampacity
rating equal to or greater than the required ampacity rating of the service entrance
conductors.
B. For Customer installations of two to six breakers, or sets of fuses, on the load side of
a termination box, or current transformer cabinet, the sum of the ratings of the circuit
breakers, or fuses shall be permitted to exceed the rating of the termination box or
instrument transformer cabinet provided the load is calculated in accordance with
NEC Article 220. That load shall not exceed the ampacity rating of the termination
box or current transformer cabinet. The NEC article 220 load calculations shall be
provided in writing to Alliant Energy.
C. The combined service or current protection rating shall not exceed the ampacity
rating of the self-contained meter socket. Self contained metering is limited to 300
amps capacity and adjustable breakers, whose maximum rating either individually or
in combination, exceeds the rating of the self-contained meter-socket, are prohibited.