Ontario Electrical Questions

I’ve inspected hundreds of panels but this is my first time seeing a screw through the main breaker. This was a 30 day warranty inspection.
Is this a new requirement?



More training needed. I try to let Paul Abernathy do this part though now.

Back fed panels require what you show.

Do you open panels?

Yes, the usual builder arrangement for a subdivision home only 30 days old. Nothing back fed.
Actually I was looking for some Ontario responses since our code differs somewhat from the US.

It’s not possible to have more training than me.

Not sure what you mean by this John? Michael is right regardless.

The panel is back fed by the main breaker.

If the main breaker fell out, the breaker and wires would still be live, presenting a safety concern.

To prevent this situation from happening, back fed breakers are required to be mechanically secured in place. I have seen this accomplished with screws and other mechanical devices.

Kevin I just meant that I have my P. Eng, Seneca/Carson Dunlop home inspection diploma, George Brown courses, OAHI courses, etc so training is not an issue.
Michael and Juan are right of course, and the panel is fed from the main breaker and grid, but I’ve never seen the main breaker fastened like this. The attached pic is what I’m used to. So why would I only see the screw in one out of a thousand panels?


It’s only needed when the panel is back fed by a breaker. If your experience is that only 1/1000 panels are back fed, then that’s why you only see the screw on 1/1000 panels.

Thanks Juan, I’m sure you and Michael are right. I’ll probably never run into this again in my area but I would still like to understand it. So would the main breaker shown here require a screw?

Thanks Juan. Rare in my area I guess.

Very informative. I also have never run in to one of these panels. Thanks for the info. This is what this forum was meant to do - inform.

Right on Bryce!