Arc flash requirements in Alberta: what the law says and what owners do

CCT 01The short answer

Alberta’s OHS Code does not contain a part on arc flash. A text search of the current consolidation finds no reference to CSA Z462, and no section requiring an arc flash study, incident energy labels or arc-rated clothing for building electricians. The Code’s only section on energized work is written for utility workers above 750 V.

What the Code does contain, and what it does not, looks like this:

None of this means arc flash is unregulated. Employers’ general duties under Alberta’s occupational health and safety legislation apply to electrical hazards like any other. It means the specific tools most people associate with arc flash, the study and the label, come from standards and contracts rather than from a line in the Code.

CCT 02Part 17 is overhead lines, and lockout is Part 15

A common mistake is to call OHS Code Part 17 the “electrical” part. It is not. Part 17 deals with overhead power lines: before work or equipment operates within 7 m of an overhead line, the employer must find out its voltage and set the safe limit of approach from Schedule 4. ¹ Schedule 4 sets that limit at 1.0 m for bare lines of 0 to 750 V ² and 3.0 m for 750 V to 40 kV. ² Those distances protect a crane operator or a lift near a pole line. They say nothing about opening a switchboard.

The part that matters inside a building is Part 15, managing the control of hazardous energy. It requires hazardous energy to be isolated with a secured energy-isolating device before equipment is serviced, repaired, tested, adjusted or inspected. ³ Each worker involved gets a personal lock with a unique mark or identification tag ³, and a worker must test and confirm that equipment is inoperative or otherwise made safe before working on it. ³ Complex group lockout procedures must be certified by a professional engineer. ³

Part 40 is the other part people misread. It requires electric utilities to follow CAN/ULC-S801-14, which applies to utility workers, not to building electricians. ³ Its rule for live-line work above 750 V, at least 2 qualified utility workers plus one at ground level, is a utility rule. ³

CCT 03Where CSA Z462 fits

CSA Z462 is the Canadian standard for workplace electrical safety, and its current edition is CSA Z462:24. ⁴ It covers the hazard assessment, work practices and protective equipment that arc flash studies and labels feed into.

In Alberta, its legal status is narrow. The only government document found that names it is a 2009 technical bulletin for property managers. It recommended that facility managers keep a copy of CSA Z462-08 and make sure people working on electrical equipment follow it. ⁵ That bulletin is a recommendation, and it cites an edition that has since been replaced several times.

So do not write, or accept in a proposal, that “Alberta adopted CSA Z462” or that “the OHS Code requires an arc flash study”. Neither statement is supported by the Code. The accurate position is that Z462 is the recognized Canadian standard, and an owner or employer can make it binding on its own sites through policy and through contracts with the people who work there.

CCT 04Owner, employer and contractor: who carries what

Arc flash responsibilities follow roles, and a building usually has several employers in it at once.

Calgary requires an annual electrical permit where a facility employs a full-time journeyman electrician. ⁶ That is a permit rule, not an arc flash rule, but it is a sign that the facility is itself an electrical employer with its own safety obligations. Property teams will find related material under property and facility management.

CCT 05What owners actually do: study, labels and program

Owners of switchgear-heavy buildings, such as plants, data centres and large offices, that adopt CSA Z462 by policy typically commission three things.

1. An arc flash study. A short-circuit and protective device coordination model of the system, with incident energy calculated at each piece of equipment in scope. The arc flash studies page explains what is in one.
2. Labels. Equipment labels generated from the study, so a qualified worker sees the hazard information for that specific board.
3. A program. Rules for who may open equipment, how energized work is justified and approved, how contractors are briefed, and when the study is reviewed.

A study only reflects the system as modelled. When the utility supply, a transformer, a breaker or a setting changes, the numbers on the labels may no longer be right. The standard sets its own review expectations; check the edition your program adopts rather than relying on a rule of thumb, and update the study whenever the system materially changes.

Maintenance is the other half. Protective devices that are not maintained may not clear a fault the way the study assumed. CSA describes Z463, its maintenance standard, as a voluntary guideline. ⁷ Owners who use it do so through preventive maintenance programs and infrared thermography.

CCT 06What a study needs from the owner

Most of the cost and delay in an arc flash study is data collection. The consultant needs:

• the utility’s available fault current and protective device data at the service, requested from ENMAX
• current single-line diagrams, or enough access to produce them
• nameplate data for transformers, switchgear, panelboards and large motors
• the model and settings of each protective device in scope
• cable sizes and lengths between them

Some of this may already exist. For services of 600 A and higher, Calgary requires the single-line diagram or shop drawings to show the fault current at every overcurrent device, the service characteristics and any series-rated combinations. ⁶ Those are short-circuit values, not incident energy, but they are a starting point for the model on newer buildings.

CCT 07Buying a study and keeping it current

Write the request so that proposals are comparable:

• Boundary. Which equipment is in scope, down to what size of panel.
• Data collection. Who collects it, whether equipment must be opened, and what shutdowns that needs.
• Deliverables. The report, the model file in a format you can give the next consultant, labels, and a list of recommendations with priorities.
• Settings changes. Who reviews recommended changes and who implements them. The consultant recommends; a qualified contractor carries out the change.
• Updates. A price for revising the model after a later project, so the study does not become stale by default.

Keep the report with the current drawings, and make every later electrical project responsible for telling the owner when it changes something the study relied on. The engineer versus contractor guide covers how design and installation responsibilities divide. Budget drivers are in the arc flash study and thermography cost guide.