Leslie Stoch, P. Eng, is principal of L. Stoch & Associates, providing electrical engineering and ISO 9000 quality systems consulting. Prior to that, he spent over 20 years with Ontario Hydro as an electrical inspection manager and engineer. Les holds a B. S. in electrical engineering from Concordia University in Montreal.
The Canadian Electrical Code and Other Requirements
The Canadian Electrical Code Part I is a voluntary standard for adoption and enforcement by Canada’s provinces and territories, with provincial and territorial amendments. We rely on the CEC to provide safety standards for installation of electrical wiring and equipment. Its stated purpose is preventing electrical fire and shock hazards. But not all of its requirements are between its covers. Sometimes, we must get into other publications to obtain more complete information. This article reviews some examples.
Sealing in Class I Hazardous Locations
This article will discuss seals. Not the cute furry ones, but the kind you need to reduce fire and explosion risks in locations containing flammable and explosive gases or vapours.
What is Grounding?
The Canadian Electrical Code’s long-winded definition of grounding is shown as: "a permanent and conductive path to the earth with sufficient ampacity to carry any fault current liable to be imposed on it, and of sufficiently low impedance to limit the voltage rise above ground and to facilitate the operation of the protective devices in the circuit.” This article discusses a number of permissible grounding requirements and methods covered by the Canadian Electrical Code.
Parallel Conductors Revisited
High ampacity services and feeders are often installed with conductors in parallel to reduce pulling tensions and for easier handling. I’m sure you are already aware that a long list of conditions comes with permission to parallel conductors. This article reviews the requirements of Rule 12-108 Conductors in Parallel along with some significant changes for such installations now provided in the 2012 Canadian Electrical Code.
Another Look at Appendix B
In an earlier article, I suggested checking for an Appendix B interpretation when applying any of the Canadian Electrical Code rules for the first time. Appendix B is there to help us better understand the intent of the CEC rules and to provide important supporting information. Here are a few more examples.
Canadian Electrical Code Appendix B
Many of the Canadian Electrical Code rules display a note, "See Appendix B.” Appendix B provides important information on interpreting and applying the rules. To be sure you’re on the right track it’s always a good idea to find out what Appendix B has to say. This article reviews a sample of excerpts from this valuable information source.
New Wiring Rules in Sections 4 and 12
The 2012 Canadian Electrical Code introduces some real changes. Many of them will be found in Sections 4 and 12 for wire and cable installations. No doubt we are already comfortable with the increased wire and cable ampacities in listed Tables 1 to 4. But there is more. This article discusses some of the more significant changes in these two sections of the CEC.
Rule 4-004, Comparable But Different
You probably noticed a number of important changes from 2009 to the 2012 edition of the Canadian Electrical Code. Section 4 – Conductors has taken the lion’s share of the changes. Rule 4-004 has received a good deal of attention. This article discusses and compares some of the similarities and differences between the 2012 version of Rule 4-004 – Ampacity of Wires and Cables and its 2009 predecessor.
The New 2012 Canadian Electrical Code
I excitedly cracked open my shiny, new Canadian Electrical Code to see what the future might bring. I found it full of surprises, most of them good, some others not so much. Here are a few thoughts.
Hazardous Gases and Vapours, Section 18
The Canadian Electrical Code, Section 18 covers electrical equipment and wiring in locations where ignition of flammable gases, vapours, dusts and fibres could result in fires or explosions. Such places are identified as hazardous locations. To minimize risks, they are classified as to the levels of risk. Electrical equipment and wiring requirements are more stringent for higher risk locations. This article discusses hazardous locations and equipment identification for flammable or explosive gases and vapours.
Neutral Grounding Devices
Neutral grounding devices (resistors) are used to control the ground-fault currents and voltages to ground of alternating current systems. Earlier versions of the Canadian Electrical Code restricted the use of neutral grounding devices to systems that supplied only 3-phase loads (no single-phase loads). But the 2006 Canadian Electrical Code was revised to change all of that. Now single-phase loads are permissible with conditions.
Maximum Circuit Loading
Maximum circuit loading is a recurring theme in the Canadian Electrical Code. Some of the code requirements are not entirely obvious without some head scratching. This article reviews Rule 8-104, maximum circuit loading which happens to be one such rule.
Overhead Power Lines and Signs — Rule 34-106
This article discusses issues that can come up when billboard signs are located too near overhead lines passing horizontal to or above the signs. Signs installed too near electrical and communication lines can create safety hazards for the owners of the signs, the sign installers, the sign maintainers and the owners of the lines who are most often electrical and communication utilities.
What’s Wrong with Rule 14-100?
Rule 14-100 has requirements for reducing wire sizes connected to splitters, junction boxes and for control circuits such as pushbutton stations. The rule prescribes the minimum construction requirements for mechanical protection and maximum unprotected lengths of conductors so as to produce a safe installation. The rule is consistent in its overall requirements except for Sub-rule 100(d), which appears to be totally at odds with the remainder of the rule.
Electrical Equipment Vaults
The Canadian Electrical Code defines a vault as "an isolated enclosure either above or below grade with fire-resisting walls, ceilings and floors for the purpose of housing transformers and other electrical equipment.” This article discusses the CEC requirements for electrical equipment vaults designed to house flammable liquid-filled equipment.
Motor Control Circuits
This article reviews two very essential safety requirements of the Canadian Electrical Code for motor control circuits, grounding and why it’s so significant that control circuits be prohibited for use as motor disconnecting means.
Grounding Resistance and Spacing of Ground Rods
As we already know, the Canadian Electrical Code requires a minimum distance of 3 m between ground rods forming an electrical system grounding electrode. Why? This article discusses the reasons for this code requirement.
Hazardous Locations — Section 18
Section 18 of the Canadian Electrical Code contains the rules for electrical equipment and wiring in locations where flammable vapours, gases or mists could create a fire or explosion, dusts capable of creating a fire or explosion or ignitable fibres are present. This article reviews a number of requirements applicable to Class I explosive gas atmospheres when classified in accordance with either the European Zone or North American Division methods of classification.
Motor Supply Conductors
It’s Complicated — you’ve probably seen this witty movie about divorce. Motor wiring rules are complicated too, but not nearly as amusing as the movie. This article reviews our complicated rules for motor supply conductors.
Rule 10-812 — Grounding Conductor Size
Rule 10-812 specifies minimum grounding conductor sizes for low-voltage electrical systems up to 750 volts. This article discusses the complexities of this rule, which as you know, was revised in the 2009 Canadian Electrical Code.
Room for Improvement
Continuous improvement takes place throughout our lives. We learn from our mistakes and as we gain experience, we try hard to avoid repeating them. Without looking too hard, we can usually identify where our decisions could have been better. The Canadian Electrical Code, under continual review, is no exception. This article discusses some places where there is still room for improvement.
GFCIs – Where are they?
The 2009 Canadian Electrical Code is peppered with references to, and requirements for ground-fault circuit interrupters (GFCIs). For very good reasons, GFCIs have become prevalent throughout many sections of the electrical code. And usually without our knowledge, they have no doubt prevented many injuries and saved many lives. This article provides a summary of these CEC rules.
Section 30 – Recessed Luminaires
Misapplication of recessed lighting can result in fires and have other serious consequences. For this reason, the National Building Code of Canada and applicable Provincial and Territorial building codes specify that recessed lighting "fixtures” must not be located in insulated ceilings unless the fixtures are designed for such installation.
Resistance Grounding and Rule 10-814
This article looks at Rule 10-814 and the bonding conductor sizes given in Table 16 as they apply to resistance grounded systems. We’ll review the question—are the Table 16 minimum wire sizes appropriate when maximum available ground faults are limited by resistance grounding, or are there any circumstances when bonding conductors might need to carry larger fault currents?
The 2009 Canadian Electrical Code – More Changes
My last article covered some amendments to the 2006 Canadian Electrical Code, applicable to the new 2009 version. There are more. This article looks at some further changes which may be of interest.
Changes — The 2009 Canadian Electrical Code
It’s here! I just received my shiny new copy of the 2009 Canadian Electrical Code and eagerly scanned it to find out what has changed. We are advised that there are 199 revisions, but many of them are editorial and will not result in changes from the 2006 CEC.
Rule 36-110, Tables 33 and 34
Rule 36-110 refers us to Canadian Electrical Code Table 33, Horizontal Clearances from Adjacent Structures, and to Table 34, Vertical Clearances for Overhead Lines, to provide minimum safety clearances for installations operating in excess of 750 volts. Table 33 provides minimum horizontal clearances between high voltage conductors and buildings.
Section 32 – Fire Pumps
Fire pumps are a special motor drive application and are critical components of life safety systems in buildings. They are a requirement of the National Building Code of Canada and the provincial building codes. Fire pumps are used to maintain adequate water pressure in sprinklers and standpipes during a fire. The building codes specify when fire pumps are required. The Canadian Electrical Code, Section 32 specifies electrical equipment and wiring requirements. This article reviews the CEC requirements for fire pumps including wiring methods, disconnection means, overcurrent protection and transfer switching.
Sections 18 and 20 – A Look at Hazardous Locations
A hazardous location is defined by the Canadian Electrical Code as a location where the hazard of fire or explosion exists as a result of flammable and explosive products. This article discusses some of the mystery surrounding hazardous locations. As we all know, many industries manufacture, process or use flammable or explosive products. A great deal of effort is taken to reduce fire and explosion hazards, but process failures, incorrect installations, inadequate maintenance or incorrect operation procedures can result in a hazardous situation.
A Look at Continuous and Non-Continuous Loads
This article discusses Canadian Electrical Code Rule 8-104 Maximum Circuit Loading. The rule is significant, since it defines how electrical circuits and equipment must be rated and it provides limitations on the continuous loading of electrical equipment. According to the CEC, loads that are ON for a long time are considered to be continuous.
Electrical system grounding is not widely understood,and it may lead to many different discussions, interpretations and a wide variation of philosophies. This article reviews some of the electrical system grounding requirements as spelled out in the Canadian Electrical Code and it throws in a few curve balls to hopefully keep things interesting.
Reasons Behind the Rules
A great deal of wisdom and experience go into writing the rules of the Canadian Electrical Code; however, the reasons may not always be clear to its users and sometimes we’re not completely satisfied to follow the rules without understanding the reasons behind them. This article reviews several rules from Section 10, Grounding and Bonding, and the reasons behind them.
Section 28 Motor Wiring Methods
Motor wiring methods are covered in Rules 28-100 to 28-112 of the Canadian Electrical Code. Wiring up a motor may seem like a pretty simple job, but we still need to consider a surprising number of details for good compliance with the code. This article will review some of the more important CEC rules for conductor ampacities as applicable to motor type, insulation class and duty service.
Section 10 of the Canadian Electrical Code, Grounding and Bonding, is probably the least well understood section of the electrical code, but it is one of the most important. Opinions abound on the absolutely correct interpretations. But almost everyone will agree that correctly installed grounding and bonding is most critical to a safe electrical installation.
Allowable Ampacities – Conductors in Cable Trays
In my experience, a discussion of conductor numbers and ampacities in cable trays is frequently met with a snicker or knowing smile. Could it be that the rule for wiring in cable trays is sometimes taken less than seriously? We have all seen trays overloaded with cables, if not at the time of installation, then in the fullness of time. Once the trays are in place as originally designed, it’s far too easy to add cables, especially when the trays follow a convenient route to the end destinations of the added cables.
Rule 10-700 Grounding Electrodes
The Canadian Electrical Code defines a grounding electrode as: "a buried metal water-piping system or metal object or device buried in, or driven into, the ground to which a grounding conductor is electrically and mechanically connected.” In other words, it’s whatever metal objects the code allows you to drive into or bury in the earth and use for grounding electrical systems. The requirements for grounding electrodes up to 750 volts are found in Rule 10-700. This rule has been substantially rewritten in the 2006 Canadian Electrical Code.
Section 18 – Getting Familiar with Some New Terms
The 2006 Canadian Electrical Code, Section 18, Hazardous Locations, provides rules for installation and maintenance of wiring and electrical equipment in hazardous locations, and classification of areas that contain flammable or explosive gases, vapours or mists, combustible dusts or ignitable fibres. The 2006 CE Code introduces us to some brand new terms and has redefined some of the old ones. In this article, we will review a number of the Section 18 language changes and some new requirements.
Some 2006 Canadian Electrical Code Changes
The 2006 Canadian Electrical Code makes a number of changes from 2002. In this article, we will visit and discuss a few changes, take a look at why they became necessary, and in some cases, review their application.
CEC 2006 – Neutral Grounding Devices, Rules 10-1100 to 10-1108
Rules 10-1100 to 10-1108 of the Canadian Electrical Code provide rules on installing neutral grounding devices (grounding resistors) used for the purpose of controlling the ground fault current or the voltage-to-ground of an alternating current electrical system. These rules have undergone some significant changes in the 2006 edition of the code.
Several of the rules in the Canadian Electrical Code are quite complicated, and it requires our close attention to get them right. This article discusses two of those rules, 28-604 for motor disconnects and 4-004 for underground conductor ampacities.
Continuous Circuit Loading, Rule 8-104
This article defines continuous loads, explains why this definition is important, and demonstrates how wiring methods affect the ratings of continuously operated electrical equipment. We begin with Canadian Electrical Code, Rule 8-302(2) which specifies the following: "A load of cyclic or intermittent nature shall be classified as continuous unless it meets the requirements of Rule 8-104(3).
CEC Method of Grounding
It goes without saying that correct grounding is vital to minimizing the risks of electrical fire or explosion and risks to personal safety. This article reviews some of the grounding methods permitted by the Canadian Electrical Code, their advantages and limitations, and reviews the model for effective grounding.
Rule 36-110, High Voltage Clearances
Both the Canadian Electrical Code (CE Code) Part I and Part III provide requirements for minimum horizontal clearances between high voltage lines and buildings, and vertical clearances between high voltage lines and grade. This article discusses the different approach taken by each.
CEC/NEC – Some Significant Differences
CEC Rule 14-100(d) permits the secondary conductors supplied by a high voltage power transformer to be protected by the transformer’s primary overcurrent protection (with no restriction in conductor length through the building). The rule requires that the wiring be mechanically protected and terminates at a single circuit-breaker or set of fuses set to protect the tap conductors against overloading.
In this article, let us review issues concerning induced current flow in the metallic coverings of single-conductor cables. Single-conductor cables have some advantages over multi-conductor cables, especially in larger sizes. Tables 1 and 3 of the Canadian Electrical Code allow us to use smaller wire sizes for single-conductor cables than Tables 2 and 4 for multi-conductor cables. Naturally, the smaller cables are always easier to handle and install than the larger, heavier ones.
CE Code: Appendix B
Canadian Electrical Code users have no doubt noticed the reminder (see Appendix B) next to the headings of many code rules. Appendix B is there to help us understand and correctly interpret the requirements of the code. It provides supplementary information including explanations, interpretations, other standards and sources of information to assist users in applying the rules so identified. It also gives us a better idea of what an inspector will expect. It’s a very good idea, in particular when applying a rule for the first time, to take a look at what Appendix B has to say.
Bonding with Our Neighbors
Both the Canadian Electrical Code and its American counterpart, the National Electrical Code provide similar definitions for the metallic means of bonding electrical equipment and raceways. In this article, I’d like to review some of the similarities and differences in the acceptable bonding methods in Canada versus the United States. Let’s begin with the definition of bonding as expressed in our separate electrical codes.
Education and Training – First Steps to Safety
In addition to all other qualifications, a good grasp of safe work practices and the Canadian Electrical Code are essential to everyone employed in the electrical industry. This is true in particular when people are engaged in electrical engineering, construction, maintenance or in operating electrical facilities. It follows that the electrical industry has a unique responsibility to ensure that people are made aware of personal safety risks and fully qualified to carry out their assigned responsibilities with safety in mind.
What is the Canadian Electrical Code – Part 1
A title page note says: "The Canadian Electrical Code, Part I is a voluntary code for adoption and enforcement by regulatory authorities.” Regulatory authorities—you know who they are—the electrical inspection authorities in all of Canada’s provinces and territories. On its own, the code has no basis in law. It only becomes the law when adopted and legislated with or without amendments by the "regulatory authorities” in each province or territory. Some jurisdictions need to make extensive amendments, while others have very few.
Making Ground-Fault Protection Work
This article looks at ground-fault protection in switchgear, what works and what doesn’t. We’ll look at some of the ways ground-fault protection may inadvertently become inoperable and what steps are needed to prevent this from happening. We will discuss some possible grounding schemes that are incompatible with ground fault sensing and may thereby disable your ground-fault protection equipment.
Looking at Signs
The Canadian Electrical Code, Section 36 defines high voltage as any voltage in excess of 750 volts. Rule 36-006 specifies all of the locations and situations where special signage is required to warn persons of high voltage hazards, awareness being extremely important for protection against electric shock. Another important consideration—access to high voltage areas must at all times be confined to people with special qualifications for entering and working in such areas and therefore all such areas must be accurately identified.
Same Language, Different Words
We Canadians and our American friends use the same language, English, to communicate among ourselves and with each other. We generally take it for granted that we will understand each other, but unfortunately that doesn’t happen automatically. This is often true, especially when we attempt to discuss precise, technical stuff such as the electrical code.
Rule 10-814 Bonding Conductor Size
Canadian Electrical Code, Rule 10-814 is where we find the minimum bonding conductor sizes for electrical circuits. It’s a fairly straight forward rule, simple to understand and it gets used quite a bit, since most electrical circuits require bonding to protect us against fire and shock hazards. But does everyone interpret and apply the rule in the same way, for instance, for motor circuits, in particular when bonding conductors contained in a cable assembly may be smaller than required by the rule?
Personal Safety and the CEC
The Canadian Electrical Code provides safety standards for installation and maintenance of electrical equipment. Its object is to prevent electrical fire and shock hazards when we follow its rules. The CEC is not intended as a design standard, but only a set of least requirements to help us achieve safe electrical installations.
Maximum Circuit Voltages
The Canadian Electrical Code in some instances limits maximum applied voltages to protect the general public and inexperienced people from electrical shock hazards. Unqualified persons are at greater risk due to their inability to identify electrical hazards and understand electrical shock risks. This article reviews some of the circumstances where the code prescribes maximum voltages to minimize exposure to serious electrical shock.
Reduced Size Taps Rule 14-100, Reduced Wiring Ampacities
This article will discuss Rule 14-100, which specifies the minimum requirements for reductions in wire sizes. Splitter box connections are among the most common applications of Rule 14-100, where conductor sizes are reduced to current ratings below the fuse or circuit-breaker settings protecting the larger conductors.
Communications System Wiring
The Canadian Electrical Code, Section 60, Electrical Communications Systems covers the requirements for communications systems wiring entering into buildings and installed throughout buildings. The code considers a communications system, any system that carries voice, sound or data signals. In addition to communications services such as telephone systems, radio, television, remote control and fire alarm systems are all deemed to be communications circuits when their signals are carried through communications lines. Although Section 60 focuses mainly on the electrical safety requirements, it also addresses a number of technical issues.
Electrical Hazards Within Reach
The Canadian Electrical Code offers several ways to protect us from electrical shock hazards when electrical equipment may be within reach, in a wet or damp area, or near grounded metal. In some cases, we are asked to maintain "out of reach” distances. When this is impracticable, a Class A ground-fault current interrupter may help to minimize the risk of electrical shock when people find themselves in simultaneous contact with electrical equipment and the earth. A GFCI may serve as a second safety barrier, should the first barrier fail to prevent an electric shock. You will recall that a Class A GFCI will trip in the event of leakage current less than 6 mA, safely within the comfort range of most people.
Electrical Wiring – 2002 CEC Revisions
As expected, the 2002 Canadian Electrical Code contains some changes in the rules for wiring. Most of the new requirements are beneficial, in that they make some new products available or provide new applications for existing products without affecting electrical safety overall. This article reviews a few of the more meaningful changes in 2002.
Effective Grounding and Bonding
This article looks at effective grounding and bonding, how it is defined by the code, and its importance to electrical safety.
NESC Substation Grounding – Part 3
After completing the soil resistance measurements at the proposed substation site, the next step is the development of a mathematical equivalent soil model that is a good approximation of the actual soil resistance data. The most common models are the uniform soil model and the two-layer soil model. The uniform soil model should only be used when there is very little variation in the average resistivity with position and depth. The average resistivity referred to in IEEE Standard 81-1983 is the same as the apparent resistivity referred to in IEEE Standard 80-2000. Further discussion of the uniform soil model can be found in Clause 13.4.1, page 56 of Std. 80.
The Canadian Electrical Code – More Changes
This article covers some changes in the rules for installing wiring and cables provided in the new 2002 edition of the Canadian Electrical Code. In earlier versions of the code, Rule 4-004(1)(d) and (2)(d) allowed the use of IEEE Standard, Power Cable Ampacity Tables IEEE 835 with the alternative of using the Appendix D underground ampacity tables to size underground cables.
Canadian Electrical Code Revisions: Grounding and Bonding Requirements
The new 19th edition of the Canadian Electrical Code has brought about some changes in the grounding and bonding rules. Not many of these are major changes. In a few instances, a change might simply be the re-arrangement of some words or the relocation of rules to more logical places in the code. In this article, we will review some of the revisions made in Sections 10, 60, and 68 as they affect grounding and bonding.
There is an increased fire hazard when recessed lighting fixtures having external temperatures in excess of 90ºC are installed in contact with thermal insulation or combustible materials. Lighting fixtures may overheat when blanketed with thermal insulation unless they have been tested, approved and marked for such use. Fire may result when there is contact with combustible materials. Fixtures used in this way may have thermal protective devices to prevent overheating or be designed in a way so as to prevent dangerous external temperatures. For the same reasons, fixtures are also usually marked for use with maximum wattage lamps.
In this article, we will review the measurements needed to ensure that substation grounding resistance and resistivity are low, so we can be sure that people are able to work safely in and around an outdoor station.
The Canadian Electrical Code, Rule 14-612 Transfer Equipment for Standby Power Systems prohibits the simultaneous connection of two or more power supplies to electrical equipment and facilities. There is an obvious exception. Rule 14-612 does not apply to parallel generation systems covered by Section 84 — Interconnection of Electrical Power Production Sources. Section 84 does apply when an electrical utility customer opts to connect and operate its own generation equipment in parallel with the electrical utility network.
Why Should the CEC Interest Electrical Utilities?
The Canadian Electrical Code Part I gives electrical utilities an exemption from the code for "installations and equipment in its exercise as a utility, located outdoors or in buildings or sections of buildings used for that purpose.” The CEC Part I is "a voluntary code for adoption and enforcement by regulatory authorities.” When adopted into the provincial regulations, this exemption is almost always maintained for work that falls within the scope of an electrical utility’s business.
Grounding and Bonding Sensitive Electronic Equipment
No doubt everyone has experienced the frustration of a PC computer crash, lockup or unreliable data. Their cause is often due to voltage noise, formally defined as "unwanted disturbances imposed upon a useful signal to obscure its information content.” Transient power system voltages and high frequency leakage currents can result in such failures and other problems. Since computer signal voltages are usually below 5 volts, it stands to reason that even very low transient noise voltages have the capability of causing questionable data or a disruption in service.
Connecting Heat-Producing Electrical Equipment
The Canadian Electrical Code provides us with rules for connections to heat-producing electrical equipment such as lighting, motors and continuously loaded equipment. Here the code has some special requirements, including minimum wiring insulation temperature ratings, reduced conductor ampacities and minimum spacings to ensure that unwanted heat is dissipated and will cause no harm to associated electrical wiring and equipment. In this article we look at a few examples where the code demands some additional wiring connection requirements.
Grounding and Bonding CEC/NEC – How Different Are They?
In Canada, the Canadian Electrical Code and, in the United States, the National Electrical Code both deal extensively with grounding and bonding issues and for the same reasons—to minimize the possibilities of electrical fires and shocks. But in many instances, each code tackles the same issue in a different way, regarding use of terminology, materials and methods of installation.
Rule 8-104 Maximum Equipment Loading
Rule 8-104 of the Canadian Electrical Code prescribes maximum permissible operating loads for electrical equipment, and maximum loads that may be carried by service, feeder and branch circuit wiring. This article looks into the requirements and limitations this rule imposes on the application of electrical equipment and wiring.
When required by the National Building Code of Canada, the Canadian Electrical Code, Section 46, Emergency Systems, Unit Equipment and Exit Signs provides installation and maintenance requirements for standby power for essential services when the regular power supply fails. Other sections of the code contain some requirements as well, including Section 32, Fire Alarm Systems and Fire Pumps. Miscellaneous requirements also show up in other sections such as Section 14, Protection and Control, and Section 10, Grounding and Bonding.
Services and Service Equipment
This article revisits some definitions and requirements covered in Section 6 of the Canadian Electrical Code, Services and Service Equipment, beginning with a review of some often mentioned terms.
Rules for Electrical Utility Supply
The Canadian Electrical Code, Section 6 provides us with some important rules for installing service equipment, wiring methods and metering. The following rules apply to electrical utilities and their customers at the service entrance, the point where an electrical utility connects to a customer’s electrical installation. This article covers some of the main requirements on the number and locations of electrical services and defines the terms used in the code.
How Important Are Connections?
Everyone understands the importance of good connections in business and in life generally. Good electrical connections are important too. The Canadian Electrical Code provides some important information and contains many rules on connecting electrical equipment. In this article we will cover a few of the many connection principles contained in the code.
Grounding and Bonding for Electronics
Computer signals are made up of a combination of zeroes and ones, and they are often below five volts DC. Voltage noise and voltage transients can disrupt the correct flow of electronic data, even when it is as low as two to three volts. A zero may be one to 1-1/2 volts and a one can be 3-1/2 to five volts. Therefore, two or three-volt system noise can change a zero to a one or vice versa, causing inaccurate data and other electronic problems.
What should happen when the electrical utility or a utility customer decides to convert the ungrounded 600 volt, 3-wire supply to a 600/347 volt, 4-wire, solidly grounded electrical supply? Some commercial and industrial businesses still prefer to use an ungrounded 600 volt supply for service continuity reasons, or to avoid the costs of converting to a grounded 4-wire supply.
Lightning and Lightning Protection
A National Standard of Canada, CAN/CSA-B72-M87 Installation Code for Lightning Protection Systems provides guidance on lightning protection. The following information may be found in the standard.
Standby Power and Transfer Switching
In this article, we will cover some of Canadian Electrical Code requirements for standby power and transfer switching. The National Building Code specifies the minimum requirements for emergency standby power supplies for different building sizes and classifications, for high-rise residential, commercial, industrial and commercial buildings depending upon size height and occupancy. It specifies the minimum electrical backup requirements for critical emergency facilities including fire alarm systems, fire pumps, elevators, lighting, exit signs, ventilation systems and emergency voice communications.
Is Everything in the Electrical Code?
Most of the time, we tend to rely exclusively on the Canadian Electrical Code for information, and for the minimum requirements on building a safe electrical installation. But is the information contained between its covers enough for our purposes – or do we need to look further afield to find out more?
Underground Conductor Ampacities Rule 4-004(1)(d) and (2)(d)
The 1998 Canadian Electrical Code has made some more changes in the rules for underground conductor ampacities. Rule 4-004 contains the requirements for maximum ampacities for single and multiple copper and aluminum 90°C conductors, direct buried and for duct banks underground, in Appendix D, Tables D8A to D16B and Appendix B, Configurations ketches B4-1 to B4-4.
Does the Electrical Code Always Make Sense?
Usually we can assume that the rules of the Canadian Electrical Code are based on some basic principles, which don’t vary a whole lot — to minimize the possibilities of electrical fire and shocks. But are the rules ever in direct conflict with each other or their principles?
Changes in the Canadian Electrical Code (1998): Sections 18 and 20
Sections 18 and 20 of the Canadian Electrical Code define hazardous locations and specify the types of electrical equipment and wiring methods acceptable in areas where flammable or explosive materials are handled, stored or produced. In such areas, the risk of a fire or explosion may exist due to the presence of flammable gases or vapours. The electrical code provides requirements for protection in hazardous locations, from electrical ignition sources, due to the effects of electrical arcing or heating.
Not long ago I wrote an article on Substation grounding for Electrical Business that raised the issue of whether one should interconnect the building reinforcing steel with the station ground electrode. A reader responded with the question of whether the best approach might be to ignore the rebar bonding. The reader is well justified in wondering whether the best approach might be to ignore the rebar bonding. The reader is well justified in wondering whether there is not an easy answer to his question as there may not be a precise answer for every possible situation.
Grounding & Bonding
The Canadian Electrical Code has a long and precise definition for grounding as: "a permanent and continuous conducting path to the earth with sufficient ampacity to carry any fault current liable to be imposed upon it, and of sufficiently low impedance to limit the voltage rise above ground and to facilitate the operation of the protective devices in the circuit.” When we talk about grounding, we are usually thinking about electrical systems.