New Ontario Electrical Safety Code updates introduce critical bonding requirements for pools and hot tubs to prevent stray voltage and shock risks.
As an electrical contractor, pools and hot tubs aren’t just another install. They’re high-liability environments where small oversights can turn into serious safety issues.
And those risks aren’t theoretical.
“We are seeing reports of shocks at hot tubs,” says ESA Technical Advisor Trevor Tremblay. “We had one example of people just relaxing in their hot tub. They started feeling some electric shocks because of a nearby metal fence.”
The latest updates to the Ontario Electrical Safety Code (OESC) are designed to address exactly these types of situations, before they become your problem to troubleshoot.
The Real Issue: Stray Voltage
If you’ve ever chased down a nuisance shock complaint, you already know how complex and time-consuming it can be.
“It really all comes down to stray current and the earth,” Trevor explains, “as electricity is trying to find every path back to its source.”
In Ontario’s multi-grounded system, that means current doesn’t always take the path you expect.
“One example,” Trevor highlights, “is when you're walking out of an in-ground pool, one foot's on the concrete and one foot's on the water.”
That difference in potential? That’s where the shock happens, and sometimes the person becomes the conductor.
This isn’t edge-case territory. There are real-life examples where this has occurred.
“We had one situation where kids were at a public swimming pool and they had to roll out of the shallow end to try to avoid being shocked.”
And the problem didn’t stop at the pool.
“Close to that pool was a municipal ball field where people were actually getting shocks from the metallic fence around the ball field.”
For contractors, this is the takeaway: you’re not just bonding a pool; you’re managing an entire electrical environment.
The Shift in the Code: Build an Equal Potential Plane
The updated OESC doesn’t try to eliminate stray current, it works around it.
“The entire goal of the change is to make everything around the pool equal potential.”
That means every conductive element — pool structure, surrounding surfaces, water, and nearby metal — needs to be tied into the same electrical plane.
“So even if there's stray current, because there's no potential difference, you won't get a shock.”
Trevor highlights three major changes, and where it impacts installations.
- Pool Shell Bonding: More Precision Required
The Code now clearly defines conductive pool shells and how they must be bonded.
The appendix clarifies that vinyl liners and fiberglass shells are considered non-conductive, but any metal parts on them still have to be bonded.
“For a concrete pool with unencapsulated metal rebar,” Trevor outlines, “the steel must now be bonded in four equally spaced locations in the wall.”
If the floor has rebar, it also has to be bonded in four spots and connected to any equipment or metal within 1.5 meters of the pool.
But here’s where it affects your workflow: “In these cases, the new code does require a copper grid — in a 300 by 300 millimeter pattern.”
Translation: If you’re working with newer materials (fiberglass mesh, encapsulated or composite rebar), you’re now responsible for installing that grid.
- Perimeter Bonding: No More Assumptions
Previously, perimeter bonding wasn’t always explicit. That’s changed.
“This is definitely new. We've never actually had a specific rule requiring bonding for the concrete around the pool,” Trevor says.
The new rule requires you to bond the rebar at four points if it exists.
“So just like with the pool shell, if there's no unencapsulated rebar, you'll have to install the copper grid. This is a number six copper grid, 300 by 300 pattern that extends 1.5 meters from the pool's edge.”
This includes:
This is one of the biggest scope (and cost) changes you’ll need to plan for.
- Concrete
- Decking
- Even grass areas
- Water Bonding: New and Non-Negotiable
If the water isn’t naturally bonded through the structure, you now have to bond it directly.
“If you have a fiberglass or vinyl liner pool that insulates the water, you have to bond the water itself.”
Trevor explains the process of bonding the water. “By installing a conductive plate or a similar corrosion resistant surface in direct and permanent contact with the pool water, the conductive surface is then connected to the main bonding grid of the pool.”
This has been a requirement in the US National Electrical Code for years, so there are products readily available. Some skimmers even have built-in water bonding devices already integrated into them.
For contractors, this is a new step that can’t be skipped — and inspectors will be looking for it.
Hot Tub Bonding: Addressing a Growing Problem
Hot tubs are also seeing increased reports of shock incidents, and the updated Code reflects that.
“The new rule requires a number six bond wire to be run around the hot tub and has to extend 450 to 600 millimeters out and be buried at least 100 to 150 millimeters deep,” Trevor explains, noting that this change is only required if the hot tub is on the ground or on a concrete slab in contact with the earth.
“If it's on a wooden deck or other insulating material that extends out one meter, then it's not required.”
Additionally, the new bond ring must be connected back to the bond in the hot tub, creating an equal potential plane between the slab and the tub.
Why This Matters for Your Business
These changes aren’t just about compliance; they directly impact your time, liability, and reputation.
“Hopefully the code change will help save people money in the long run,” Trevor says. “Finding the source of a shock can be time-consuming and possibly getting the utility involved, which can be costly.”
And that's actually one of the big reasons for the recent code changes.
“The new rules might seem costly upfront, but they are designed to prevent these problems from ever happening in the first place,” he says, giving owners of the pool a lifetime of worry-free swimming.
But as the system ages, without proper maintenance, things can come apart and affect the proper bonding. And when something goes wrong?
“As the contractor, the homeowner will call you first to solve this problem, which may involve countless hours of investigation and even sometimes involvement of the utility.”
The updated Code is designed to prevent that scenario entirely.
Key Takeaways for Contractors
- Stray voltage is a real issue in pool and hot tub environments
- The OESC now requires full equal potential bonding across all elements
- New requirements include perimeter bonding and water bonding
- Hot tubs now require additional bonding depending on installation
- Proper installation upfront saves hours of troubleshooting later
These updates reflect a shift in approach: build it right the first time, or be prepared to do a costly fix it later.
For electrical contractors, that means adapting to new bonding requirements, understanding how materials impact conductivity, and ensuring every install meets the the Code.
Because when it comes to pools and hot tubs, safety isn’t just part of the job — it is the job - and keeps your customers safe.
As always, contractors should refer to the current edition of the Ontario Electrical Safety Code, applicable ESA bulletins, and manufacturer specifications to ensure full compliance.
Follow Grounded in Ontario wherever you get your podcasts. Got a technical question or an idea for an upcoming topic on our show, we want to hear from you! Email us at podcast@esasafe.com.
