Last edit: 03/05/2023
From January 2022 C22.2 N°286 becomes the reference Standard for the conformity of industrial control panels in Canada, the equivalent of UL 508A for USA.
In the past the reference Standard was C22.2 N°14: Industrial control equipment. But that is not really a Standard for the conformity of control panels of machinery, since it was written for the conformity of electrical components like contactors (manual motor controllers in North American technical language).
What does this change mean?
The change is quite important for Italian machinery manufacturers used to apply UL 508A for the Canadian market as well. Since C22.2 N°14 is not really applicable to Machinery industrial control panels, UL 508A has always been a good reference Standard also for Canada. The problem now is the differences between UL 508A and C22.2 N286, and there are a few.
The most relevant difference: compensation of conductors ampacity
Probably the most relevant one is that UL 508A does not require cable ampacity compensation for more than 3 cables next to each other. That means a copper AWG 10 conductor has an ampacity of 30 A; please refer to Table 28.1 of UL 508A. If 9 conductors run inside a control panel wiring thought, the ampacity is still 30 A.
Now, the situation just explained was all right for Canada until January 2022. From that moment, the reference table is Table 7 of C22.2 N°286. A copper AWG 10 conductor has an ampacity of 27 A if the control panel is ventilated. That ampacity has to be corrected for the number of conductors in a wiring thought according to table 8. That means, if 9 cables run inside a control panel wiring thought, the ampacity becomes 19 A: it is downgraded!
An extreme situation is for a non ventilated panel: in case of 9 copper AWG 10 conductors running in a wiring thought, the ampacity becomes 13 A! Quite a difference with respect to 30 A according to UL 508A.
Currently the latest edition of C22.2 N°286 is 2017. A new edition is under way, but you should not expert to see an update before the end of 2022. That means that you need to be careful when designing an Industrial Control Panel for Canada.
Conductor ampacity calculation
Rule 4.6.3 of C22.2 N°286 provides the reference to Table 7. Hereafter the language:
[C22.2 N°286: 2017] Rule 4.6.2 Insulated conductors shall be suitable for the specific conditions of use intended with respect to voltage, temperature, and grouping. Conductors shall not be smaller than No. 24 AWG, and the temperature rating shall be not less than 90 °C unless investigation proves the suitability of other conductors.
- The requirements of this Clause apply only to the wiring furnished on or in industrial control equipment as a part of the equipment. They do not apply to the supply wiring run to control equipment, to motors, or to other apparatus.
- For motor and control-circuit applications, the use of Tables 7 and 8 as a guide in selecting the conductor sizes in industrial control panels can obviate the need to perform a temperature test on the wire. Conductor sizes for other applications (e.g., heating loads) are subject to investigation.
Please consider that this language is valid only for cables inside the Industrial Control Panel.
For the ampacities of conductors outside the machinery control panel, the reference is C22.1, also called CE Code.