Guide to the Canadian Electrical Code, Part I — Installment 7

Apr 7, 2020

By William (Bill) Burr

Section 14 is a general section of the Code and the scope applies to all electrical circuits and apparatus installed in accordance with the requirements of the Code, unless amended or modified by other sections. As with other sections of the Code, the Appendix B notes contain much valuable information on the use of these rules and outlines that other sections of this Code may provide additional protection requirements for specific circuits, equipment or conductors.

General requirements

Rule 14-010 specifies that protective and control devices are required to be provided for electrical apparatus and ungrounded conductors. It provides the most fundamental requirement in the Code to install control devices:

• in order to manually disconnect all ungrounded conductors of a circuit at the point of supply simultaneously, (multi-wire branch circuits supplying fixed lighting loads or non-split receptacles excepted), or

• to automatically open the circuit if a current in a circuit reaches a value that will produce dangerous temperatures in conductors or apparatus, or,

• in the event of a ground fault, or voltage failure

The rule is needed to prevent damage or injury due to overloads, short circuits or ground faults, and hazards caused by a low or no voltage situation. Protective devices include fuses and circuit breakers while control devices include switches as well as circuit breakers. Note that a fuse is not a control device and must be used in conjunction with a switch where control is required.

Rule 14-012 specifies that protective and control equipment must be selected in accordance with ratings sufficient for the available fault current, and for the current level it is required to interrupt, in addition to the voltage involved. This rule is also very important for electrical systems designers and installing contractors, as it mandates that only an O/C device rated for the available fault current may be used in an electrical installation.

Rule 14-014 Series rated combinations provides that a downstream circuit breaker, with a lower interrupting rating than the available system fault current level, can be used in a series rated combination, with a fully rated upstream overcurrent device, such that the upstream breaker opens before the downstream breaker, when a high level of fault current is detected. These sub-rules provide the conditions for allowing this arrangement. Note that the downstream breaker is marked with the specific upstream overcurrent device required.

Rule 14-016 Connection of devices requires that, with a few exceptions as noted, protection or control devices must never be connected in a grounded conductor.

Protective devices

General

Rules 14-100 to 14-114 apply to all protective devices.

Rule 14-100 requires each ungrounded conductor to be protected by an overcurrent device, at the point where it receives its supply and at each point where the size is decreased, with the exceptions as outlined in paragraphs (a) to (g). It should be noted that exceptions listed in these paragraphs are commonly used by electrical designers and contractors.

Rule 14-102 outlines requirements for ground fault protection and includes: provision, maximum setting, ampere ratings, protection, location and arrangement of sensors and schemes, where two or more protective devices are used in series for ground fault coordination.

Rule 14-104 Rating of overcurrent devices — generally the rating should not exceed the allowable ampacity of the conductors, as per Section 8, which these O/C devices protect. Note: alternatively consult Table 13, within the maximum value of 800 A.

Rule 14-106 requires that overcurrent devices must be accessible and grouped where practicable.

Rule 14-108 requires that overcurrent devices be enclosed in cut-out boxes, cabinets or part of an assembly such as switchboards, panelboards, or controllers and located away from easily ignitable material and dampness, and only accessible to authorized persons.

Rule 14-110 sets out requirements for grouping of overcurrent devices at a distribution centre.

Rule 14-112 provides restrictions for overcurrent devices in parallel.

Rule 14-114 restricts the use of supplementary protectors for branch circuit protection

Fuses

Rule 14-200 outlines the marking required of time-delay and low-melting point types of fuses.

Rule 14-202 limits the use of plug fuses to circuits of 125v line-to-line or 150v to ground.

Rule 14-204 requires that plug fuses be non-interchangeable so that a larger rating can’t be used.

Rule 14-206 requires that fuse holders for plug fuses must be the covered type where accessible to unauthorized persons.

Rule 14-208 outlines procedures for choosing the correct current rating for fuses based on voltage and class as outlined in Rule 14-212.

Rule 14-210 requires that only properly rated fuses are to be used and prohibits bridging or short-circuiting.

Rule 14-212 outlines criteria for selection of fuses. These are cross-referenced with Table B 14-1.

Circuit breakers

Rule 14-300 specifies that circuit breakers must be trip-free type and indicate if they are open or closed.

Rule 14-302 requires that circuit breakers must be constructed so that they protect all ungrounded conductors in the circuit with exceptions as noted.

Rule 14-304 specifies that circuit breakers must be designed so that it is difficult for non-authorized persons to alter the current or tripping time.

Rule 14-306 notes that tripping elements for circuit breakers must be as specified in Table 25.

Rule 14-308 requires battery-controlled circuit breakers to

• be continuously monitored for battery voltage
• auto trip and sound an alarm where battery voltage drops below operational level
• have a warning notice that battery power must be available before the circuit breaker is closed

Control devices

General

Rules 14-400 to 14-416 apply to all control devices.

Rule 14-400 specifies that control devices have a rating suitable for the loads to be interrupted.

Rule 14-402 requires a disconnecting means for all fused circuits, except as noted.

Rule 14-404 notes that control devices ahead of overcurrent or overload devices must render the overcurrent or overload device dead when the control device is open.

Rule 14-406 requires control devices to be located so that they are readily accessible.

Rule 14-408 specifies that control device positions must be marked to indicate on or off.

Rule 14-410 requires that control devices be enclosed in metal or other fire resisting material, if accessible to unauthorized persons.

Rule 14-412 requires that control devices be grouped where practicable.

Rule 14-414 requires that electrical equipment supplied by two or more sources of voltage be

• controlled by a single disconnecting means, or
• grouped together and provided with warning signs placed on or adjacent to each disconnecting means indicating that all disconnecting means must be opened to ensure complete de-energization of the equipment

Disconnecting means for control circuits originating beyond the equipment, and not exceeding 150 volts-to-ground, need not meet the above but all bare live parts must be protected against inadvertent contact by means of barriers with warning signs indicating more than one source of supply.

Rule 14-416 notes that control devices used only for switching must disconnect all ungrounded conductors in the circuit.

Switches

Rule 14-500 requires that switches be operable without exposing live parts in the off position, unless they are inaccessible to unauthorized persons.

Rule 14-502 requires that knife switches be mounted so that gravity can’t close them.

Rule 14-504 specifies that knife switches used for isolating be limited to a maximum rating of 600A at 750 V, unless of special design.

Rule 14-506 requires that all switches be connected so that moving blades and contacts are dead when in the open position, with some exceptions as noted.

Rule 14-508 specifies that AC/DC switches be rated appropriately for the load and T rating as noted.

Rule 14-510 outlines that manually operated general-use AC switches

• have an ampere rating not less than the current rating of the load for 120 V tungsten-filament lamps that are non-inductive or inductive loads with a lagging 75% power factor, or

• have a current rating not less than 15 A with a voltage of 120 or 277 V, and

• be mounted in flush-device boxes, surface-type boxes, special boxes or complete self-enclosures

Rule 14-512 outlines that manually operated general-use 347 V AC switches

• be used only for non- inductive loads except tungsten-filament lamps and for inductive loads with a power factor not less than 75% lagging

• have a current rating not less than 15 A

• switches mounted in boxes not be interchangeable with those referred to in Rules 14-508 and 14-510.

Rule 14-514 requires that switches referred to in Rules 14-508 and 14-512 not be ganged or grouped in the same enclosure without permanently installed barriers, in circuits exceeding 300 volts-to-ground.

Protection and control of miscellaneous apparatus

Rules 14-600 requires that receptacles not be connected in circuits that exceed the current rating of the receptacle.

Rule 14-602 specifies that additional control devices for portable cord and plug connected appliances, rated 1300 W or less, are not necessary.

Rule 14-604 requires that where outlets are controlled from more than one point, the switching is done only in the ungrounded circuit conductor.

Rule 14-606 outlines that panelboards, except those where 90% of the overcurrent devices supply feeders or motors, must be protected by an overcurrent device rated no greater than the panelboard. The overcurrent device may be in the primary of a transformer supplying the panelboard if the panelboard rating is not less than the overcurrent rating multiplied by the primary to secondary voltage ratio of the transformer.

Rule 14-608 requires that remote control circuits of remotely controlled apparatus:

• be arranged so they can be disconnected from their supply at the controller, or

• the disconnecting of the apparatus from the supply circuit may also disconnect the remote control circuit from the supply circuit

Rule 14-610 specifies that where fuses protect circuits where more than 50% is a cycling load, such as space heaters, clothes dryers, or water heaters, they be time-delay or low-melting-point fuses as per Rule 14-200 or Rule 14-212 b), except in dwelling units.

Rule 14-612 requires that transfer equipment for standby power systems prevent inadvertent interconnection of normal and standby sources of supply.

Solid-state devices

Rule 14-700 requires that solid-state devices not be used as isolating switches or as disconnecting means.

Rule 14-702 specifies that where failure or leakage of a solid-state device could result in transfer of energy between two or more power sources, a supplementary disconnecting means be provided

• as an integral part of the solid-state device
• installed as close as practicable to, and
• in sight of, the solid-state device

to prevent transfer of energy between the different power sources when opened.

Rule 14-704 requires that suitable warning notices be placed on the supplementary disconnecting means stating that

• the disconnecting means be opened in the event of a failure of any of the power sources or in the event of servicing of any component in the circuits of the other power sources

• both line and load terminals may be energized when the disconnecting means is open, and
on all other upstream disconnecting means stating that

• an alternative power source(s) exists in the circuit

• the supplementary disconnecting means must also be opened to prevent the possibility of feedback from the alternative source(s)
In the next installment we will be discussing Section 16 – Class 1 and Class 2 Circuits.

William (Bill) Burr is the former Chair of the Canadian Advisory Council on Electrical Safety (CACES), former Director of Electrical and Elevator Safety for the Province of BC, and former Director of Electrical and Gas Standards Development and former Director of Conformity Assessment at CSA Group. Bill can be reached at Burr and Associates Consulting billburr@gmail.com.