Electrical circuit breaker compatibility

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Posted by: from Toronto
5/1/2018 at 11:48:16 AM

I live in a condominium in Toronto - a factory converted to a condo in 2002. The Siemens electrical panel in my suite has a mix of Siemens and Cutler-Hammer breakers. An electrician told me yesterday that this mix is incompatible, not to code and must be changed. Is this true?

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Date/Time5/1/2018 at 1:16:33 PM

The circuit breaker brand should match to the brand of the panel. The dsigned tension of the push in circuit breakers should be compatible to the bus bar. If this is not followed the bus bar and the cb may create heat and will lead to burning.

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Date/Time5/1/2018 at 1:21:19 PM

Hi Diana.

Thanks for posting your question on TrustedPros! Good question. We get asked that frequently. Yes, it does matter that the correct breaker is installed. In your case, it should't be too costly to replace with correct breaker. The good news is, when the electrician is there changing the breaker he/she can check to ensure the panel is in good order, all breakers are sized correctly and also see if there is any damage of conductors. All this can save you from costly repairs in the future.

All the best.


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Jason from Total Electric in Apsley
Date/Time5/1/2018 at 1:26:12 PM

They definitely work in a pitch, not a long term solution though. I follow the same mindset as the electrician. They are probably not CSA approved to be installed in a different brand panel. As the condo has had a final with the current conditions, hopefully, you should not be required by code to change them. For the price of a few breakers a proper install might be worth it. I would also recommend it if unlicensed contractors have installed them over the years.

Thanks, Jason

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Date/Time5/1/2018 at 1:49:01 PM

Yes that is true. The Siemens panel must have Siemens breakers.

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Robert from ElecTriLight Ltd. in Oakville
Date/Time5/1/2018 at 6:44:11 PM

100% must be replaced with the manufacturers brand. "physically fit in" does not mean "electrically connected" properly to the bus bar. If I was there, I would simply replace piece for piece and not charge you if the breakers are the same price and era.

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Date/Time5/6/2018 at 1:05:14 PM

Everyone here has provided the correct advice, regardless of what province you live in, the breakers must match the panel. There is a compatibility sheet for obsolete breakers, but that is not the case here.

So you are from Ontario, so must call a Licensed Electrical Contractor (LEC), that has an ESA ECRA number to change these breakers and a permit must be taken out and an inspection completed. What I might suggest is that you engage the Condo Board and have them take the lead on this as if your unit is mis-matched, likely so are many others and it would be an issue for the Condo Board and not the individual owners I think to cover these costs of the noncompliant work.


John Kuehnl-Cadwell

Master Electrician

Datawise Solutions Inc

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