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Discussion Starter · #1 ·
Does anyone know if CEC allows 14/2 wire for 15A 240V heat pump circuit? (RLA: 12.3A - LRA: 57.8A)
 

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Yes. Look at Section 28-706 and 708.

28-706 Conductor ampacity
The ampacity of conductors of a branch circuit supplying a motor-compressor, or equipment consisting of one
or more motor-compressors and other loads, shall be based upon the marked rated load current of the motorcompressor
or equipment and shall comply with the general requirements of this Section.

28-708 Overcurrent protection
(1) Except as permitted in Subrule (2), each ungrounded conductor of a branch circuit feeding a motorcompressor
shall be protected by an overcurrent device rated or set at not more than 50% of the locked
rotor current of the motor-compressor, unless such a device will not permit the motor-compressor to start,
in which case the rating or setting shall be permitted to be increased to a value not exceeding 65% of the
locked rotor current of the motor-compressor.
(2) Subrule (1) shall not be deemed to require use of overcurrent devices rated or set at less than 15 A.

You could legally put it on #14 wire(20A ampacity in 75C column of Table 2) with up to a 25A breaker. How far is the heat pump from the panel? If you look on the name plate it will say minimum circuit ampacity and maximum overcurrent protection.
 

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Discussion Starter · #3 ·
The heat pump is roughly 15 feet from the panel.
The data sheet gives the following information:
Minimum branch circuit ampacity: 15
Maximum branch circuit ampacity: 20

Thanks.
 

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Minimum branch circuit ampacity: 15
Maximum branch circuit ampacity: 20
I'll ask you, with that MCA what do you think?
 
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You could legally put it on #14 wire(20A ampacity in 75C column of Table 2) with up to a 25A breaker. How far is the heat pump from the panel? If you look on the name plate it will say minimum circuit ampacity and maximum overcurrent protection.
If I'm not mistaken, in this case it would only be viable up to 15 A on the #14 due to rule 14-104(2)(a): Except as provided for by subrule (1)(c), the rating of the overcurrent protection shall not exceed 15 A for No. 14 AWG copper conductors.

Unless there is a special provision in the code for heat pumps that I do not know of at this time.
 

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If I'm not mistaken, in this case it would only be viable up to 15 A on the #14 due to rule 14-104(2)(a): Except as provided for by subrule (1)(c), the rating of the overcurrent protection shall not exceed 15 A for No. 14 AWG copper conductors.

Unless there is a special provision in the code for heat pumps that I do not know of at this time.
Negative, 28-706 is an exception to 14-104.

14-104 Rating of overcurrent devices (see Appendix B)
(1) The rating or setting of overcurrent devices shall not exceed the allowable ampacity of the conductors that
they protect, except
(a) where a fuse or circuit breaker having a rating or setting of the same value as the ampacity of the
conductor is not available, the ratings or settings given in Table 13 shall be permitted to be used
within the maximum value of 600 A;
(b) in the case of equipment wire, flexible cord in sizes Nos. 16, 18, and 20 AWG copper, and tinsel cord,
which are considered protected by 15 A overcurrent devices; or
(c) as provided for by other Rules of this Code.

(2) Except as provided for by Subrule (1)(c), the rating of overcurrent protection shall not exceed
(a) 15 A for No. 14 AWG copper conductors;
(b) 20 A for No. 12 AWG copper conductors;
(c) 30 A for No. 10 AWG copper conductors; and
(d) 15 A for No. 12 AWG aluminum conductors.
 

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If I'm not mistaken, in this case it would only be viable up to 15 A on the #14 due to rule 14-104(2)(a): Except as provided for by subrule (1)(c), the rating of the overcurrent protection shall not exceed 15 A for No. 14 AWG copper conductors.

Unless there is a special provision in the code for heat pumps that I do not know of at this time.
Section 28 over rules section 14. Very common to see a small wire on a large breaker when dealing with motors.
 

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The rule 14-104 limiting #14 to 15A always applies, except when another section of the codebook says you can do otherwise. Heat pump should fall under section 28-700, so whatever the rules say in there on over current protection would trump 14-104.

Edit: Oh nevermind, you just got slammed with replies. lol
 
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