wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Change:
230.42(A) General.
Service-entrance conductors shall have an ampacity not less than the maximum calculated load to be served. Conductors shall be sized not less than the larger conductor of 230.42(A)(1) or 230.42(A)(2). Ampacity shall be determined in accordance with 310.14 and comply with 110.14(C). The maximum current of busways shall be that value for which the busways have been listed or labeled.
Informational Note No. 1: See UL 857, Standard for Safety for Busways, for information on busways.
Informational Note No. 2: See Article 120 for calculating the load supplied by the conductors.
(1) Continuous and Noncontinuous Loads.
Where the service-entrance conductors supply continuous loads or any combination of noncontinuous and continuous loads, the The minimum service-entrance conductor size shall have an ampacity in accordance with 110.14(C)(1) not less than the sum of the noncontinuous loads plus 125 percent of continuous loads.
Exception No. 1: Grounded conductors that are not connected to an OCPD shall be permitted to be sized at 100 percent of the sum of the continuous and noncontinuous load.
Exception No. 2: Conductors shall be permitted to be sized at 100 percent of thesum of the continuous and noncontinuous load if they terminate to an OCPD where both the OCPD and its assembly are listed for continuous operation at 100 percent of their rating.
(2) Application of Adjustment or Correction Factors.
The minimum service-entrance conductor size shall have an ampacity not less than the maximum load to be served after the application of any adjustment or correction factors.
Substantiation:
Several small changes for clarity without any change in the intended meaning:
(1) The first sentence of 230.42(A) is redundant with 230.42(A)(2). They express identical requirements.
(2) The deleted phrase "Where the service-entrance conductors supply continuous loads or any combination of noncontinuous and continuous loads" always applies, as any set of loads is a combination of continuous and noncontinuous loads. So its presence adds nothing, and deleting it improves clarity.
(3) Emphasize that the ampacity referred to in 230.42(A)(1) is ampacity without adjustment and correction, as discussed in 110.14(C)(1). 210.19(A)(1) has such a reference.
(4) The phrase "the sum of the continuous and noncontinuous load" is more simply expressed as "the load".
(5) Any OCPD is listed for use at 100% of its rating, just non-continuously. So this exception should only apply when the OCPD is listed for continuous use at 100% of its rating.
230.42(A) General.
Informational Note No. 1: See UL 857, Standard for Safety for Busways, for information on busways.
Informational Note No. 2: See Article 120 for calculating the load supplied by the conductors.
(1) Continuous and Noncontinuous Loads.
Exception No. 1: Grounded conductors that are not connected to an OCPD shall be permitted to be sized at 100 percent of the sum of the continuous and noncontinuous load.
Exception No. 2: Conductors shall be permitted to be sized at 100 percent of the
(2) Application of Adjustment or Correction Factors.
The minimum service-entrance conductor size shall have an ampacity not less than the maximum load to be served after the application of any adjustment or correction factors.
Substantiation:
Several small changes for clarity without any change in the intended meaning:
(1) The first sentence of 230.42(A) is redundant with 230.42(A)(2). They express identical requirements.
(2) The deleted phrase "Where the service-entrance conductors supply continuous loads or any combination of noncontinuous and continuous loads" always applies, as any set of loads is a combination of continuous and noncontinuous loads. So its presence adds nothing, and deleting it improves clarity.
(3) Emphasize that the ampacity referred to in 230.42(A)(1) is ampacity without adjustment and correction, as discussed in 110.14(C)(1). 210.19(A)(1) has such a reference.
(4) The phrase "the sum of the continuous and noncontinuous load" is more simply expressed as "the load".
(5) Any OCPD is listed for use at 100% of its rating, just non-continuously. So this exception should only apply when the OCPD is listed for continuous use at 100% of its rating.