1. (a) Secondary voltages. The voltage at the utility's point of delivery, as installed for each consumer, shall be maintained within the limits specified in (1) through (4) of this subsection. If a utility adopts any standard voltage not included in the table in (4) of this subsection, it shall advise the Commission that the Commission may establish appropriate voltage limits. Where three-phase service is provided, the utility shall exercise reasonable care to assure that the phase voltages are balanced. The preferred and tolerable voltage ranges conform to the current version of ANSI Standard C84.1, or equivalent ANSI standard as later amended.

   		PREFERRED VOLTAGE		TOLERABLE VOLTAGE
   NORMAL		RANGE		RANGE
   VOLTAGE		MINIMUM	MAXIMUM		MINIMUM	MAXIMUM
   120		114	126		110
   208Y/120		197Y/114	218Y/126		191Y/110	220Y/127
   240/120		228/114	252/126		220/110	254/127
   208		197	218		191	220
   416Y/240		395Y/228	436Y/252		381Y/220	440Y/254
   480/240		456/228	504/252		440/220	508/254
   460Y/265		437Y/252	483Y/279		422Y/244	487Y/281
   480Y/277		456Y/263	504/Y291		440Y/254	508Y/293
   440		418	462		403	466
   480		456	504		440	508
   832Y/480		790Y/456	873Y/504		762Y/440	880Y/508
   600		570	630		550	655

   1. (1) Preferred secondary voltages. The secondary voltage described above shall normally be maintained within the preferred range specified in the table in (4) of this subsection.
   2. (2) Tolerable secondary voltage. The secondary voltage described above will be permitted in the tolerable range specified in the table in (4) of this subsection under abnormal conditions if it is limited in frequency of occurrence and duration, providing that measures are initiated within a reasonable period of time to bring the voltage within the preferred range.

   3. (3) Emergency secondary voltages. Voltages outside the limits specified in (4) of this subsection may infrequently occur due to:

      1. (A) Addition of significant loads without proper notice to the utility.
      2. (B) Adverse action of the elements.
      3. (C) Failure of principal supply line or equipment necessitating use of alternate routes.
      4. (D) Temporary separation of part of the system from the main system.
      5. (E) Causes beyond the control of the utility.
   4. (4) Table.

2. (b) Primary voltages. The following limits shall apply where the utility supplies service at primary voltage.

   1. (1) Industrial consumers. For services rendered principally for industrial or power purposes, the voltage shall not exceed ten percent (10%) above or ten percent (10%) below the nominal voltage of the low side of the transformer.
   2. (2) Special contract extension. The limitations in (1) of this subsection do not apply to special contracts in which the consumer specifically agrees to accept service with a different voltage regulation.

Amended at 10 Ok Reg 2633, eff 6-25-93

Amended at 16 Ok Reg 2237, eff 7-1-99

Amended at 31 Ok Reg 1030, eff 9-12-14