A confined space entry for electrical work requires a written entry permit, continuous atmospheric monitoring, ventilation, and a tested rescue plan before anyone goes in. In Alberta and BC, this rule applies to transformer vaults, cable trenches, tanks, ducts, and any enclosed space with limited entry or exit and the potential for a hazardous atmosphere.
What Counts as a Confined Space on an Electrical Job Site
A confined space is any area large enough to enter, with limited or restricted means for entry and exit, that is not designed for continuous occupancy. On electrical sites this usually means transformer vaults, underground cable trenches, switchgear rooms with restricted access, manholes, and storage tanks that house wiring or instrumentation. The space itself is rarely the danger. The atmosphere inside it is.
Alberta’s OHS Code and WorkSafeBC regulation both treat confined space entry as a permit-required activity. That means a site cannot treat a vault the same way it treats an open panel, even when the electrical work itself is identical.
The Permit to Entry Process
Before a crew enters, a competent person completes a written entry permit that documents the hazards present, the atmospheric test results, the ventilation plan, and the names of everyone entering and attending. The permit stays active for the duration of the work and gets closed out when the crew exits. No permit, no entry.
- Identification of the hazards specific to that space
- Atmospheric test results recorded before entry
- Names of the entrant, attendant, and supervisor
- Communication method between entrant and attendant
- Rescue plan specific to that space
Atmospheric Testing: What Gets Measured
A calibrated gas monitor checks oxygen level, combustible gas concentration, and common toxic gases before entry and continuously while the crew is inside. Oxygen needs to sit between 19.5% and 23%. Any reading outside that range, or any combustible or toxic gas reading above the site’s action level, stops entry until the space is ventilated and retested.
This is the step most often rushed on a tight schedule, and it is the one that protects the crew from an atmosphere that looks and smells completely normal.
Ventilation and Rescue Planning
Mechanical ventilation runs before entry and continues while the crew works, especially in vaults and tanks with no natural airflow. A rescue plan has to be specific to the space, not a generic company policy. That means knowing how a non-ambulatory worker gets removed from that exact vault, who performs the rescue, and how emergency services get notified if the situation is beyond the crew’s own capability.
Who Can Perform Confined Space Work
Every entrant and attendant needs confined space entry training specific to the hazards on that site, along with the standard electrical certifications for the work being performed. Pro Call Electric’s crews carry confined space, fall protection, and H2S Alive certification, and every entry runs with continuous gas monitoring and a tested rescue plan in place before the permit gets signed.
Common Mistakes That Put Crews at Risk
- Treating a vault as basically open air because the last entry was uneventful
- Testing the atmosphere once and skipping continuous monitoring
- Using a rescue plan written for a different space
- Sending one person in without an attendant stationed outside
Frequently Asked Questions
What is considered a confined space in Alberta and BC?
Any enclosed or partially enclosed area not designed for continuous occupancy, with restricted entry or exit, and the potential for a hazardous atmosphere. On electrical sites, this includes vaults, tanks, ducts, and some switchgear rooms.
Do I need a new permit for every entry?
Yes. A permit is specific to that entry, that day, and the conditions measured at the time. A previous permit for the same space does not carry over.
What training does a confined space entrant need?
Confined space entry training that covers atmospheric hazards, ventilation, and rescue procedures, in addition to the trade certifications required for the electrical work itself.
Pro Call Electric only enters confined spaces with continuous gas monitoring, ventilation, and a tested rescue plan in place. See our confined space services or contact us to talk through a site-specific plan.