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Main breaker trips when large appliances are on simultaneously

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Posted by: from Brampton
3/4/2013 at 1:34:58 PM

Hey everyone,

I've had this problem for probably 5 years now. The main breaker would trip whenever the following combination of appliances were running simultaneously: dryer+oven, dryer+A/C, A/C+oven. This means power to the entire house shuts off when this happens.

Now it happens whenever the dryer runs even by itself. It has also happened at seemingly inappropriate times like when the toaster is on or toaster+vacuum cleaner.

I had a friend of a friend who's an electrician take a look at the breaker panel and he said everything looked fine (but by a quick judge of character, I don't trust his opinion).

If anyone can provide me with some feedback and direction it would be appreciated.

Thanks,

Boris

REPLIES (14)
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Date/Time3/4/2013 at 2:17:05 PM

If that was happening at my house I would have a licensed electrician come in and have a look at it ASAP.

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Date/Time3/4/2013 at 2:57:18 PM

Hi,

First off, the main breaker is not built / designed to trip multiple times. It is designed as the last line of defense between you and hydro. I think I read once in a design spec sheet somewhere that a main breaker can break 5 - 10 times before it is recommended to be replaced.

So, on that note... your main may be too weak to properly manage the heat loading of multiple appliances.

Now to the assumptions...

I gather you are using more power then your main panel was set-up for. For example... if you are on a 60A service, you cannot run a stove, A/C, and toaster on that service because it draws too much power for what the breaker panel was designed to handle.

Get an electrician to do a load calc (every certified electrician can do this calculation). This will tell you what your service requirement is.

There are many options to help you deal with the problem, but the most economical once everything is said and done is to upgrade your service panel to 150A or 200A. The average home now requires 200A for its basic loads.

Hope that helps a little.

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Robert from Electrilight Ltd. in Oakville
Date/Time3/4/2013 at 3:58:30 PM

Hi Boris,

You didn't mention the size of the main, but if it is a small 60 amp service, best thing is to upgrade it to minimum 100amp service entrance which could result in some extra work and expense for a meter change and conduit.

What is the age of the panel/home? Is it breakers of fuses?

Some breakers will fail easily if they have been exposed to heavy loads and have their thermal trips wearing out.

What type of panel is it as it may be as simple as replacing the main breaker, which can cost from $70 to $200 depending on panel type.

This change MUST be done with the power cut off as 240 volt and very high amperages are possible which could result in a fatal arc-flash and possibly a house fire if done incorrectly. So don't let an unqualified or unlicensed person tell you they'll do it for $50 cash. This could result in serious injuries.

Robert (master electrician/owner)

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Date/Time3/4/2013 at 4:24:02 PM

Hi Boris

Good advice by both Ivan and Robert. If the main breaker is tripping, it is doing its job. So the main breaker tripping is not the problem, it is the loads that are combined that are higher than the total capacity of the panel as mentioned.

As Ivan correctly points out, the best advice is to get a load calculation done to see what your demand is. An experienced electrician might be able to look at the house and the connected loads and determine if you need 100 or 200 amp. It is less expensive in most cases to go with a 200 amp then a 150 amp, so your choices are either 100 or 200 pretty much. Having said that you have options from 100, 125, 150 and 200 and larger of course.

Get three ESA certified electrical contractors in there to take a look and give you prices on the work. Then you will be able to compare all three and pick the one that gives you the best value for the dollar spent.

Cheers

John

Kohn Kuehnl-Cadwell

Master Electrician

Datawise Solutions Inc

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Date/Time3/4/2013 at 4:25:34 PM

In such a rush I can't even spell my own name right :-)

Cheers

John

John Kuehnl-Cadwell

Master Electrician

Datawise Solutions Inc

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Boris in Brampton
Date/Time3/4/2013 at 6:56:55 PM

Ivan, Robert, John: Thanks for the great advice and fast responses.

I've taken a look at the panel and found that it's a FPE Stab-lok 125A panel. I've attached a picture I just took of the inside of the box.

In any case, I'll be getting some licensed electricians in here to take a look.

Thanks,

Boris


Main breaker trips when large appliances are on simultaneously
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Boris in Brampton
Date/Time3/4/2013 at 7:00:05 PM

Oh and I'm not sure when the house was built but it's not ancient. It's a small 3-bedroom townhouse (Hansen Rd. N., Brampton) maybe around 40 years old.

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Robert from Electrilight Ltd. in Oakville
Date/Time3/4/2013 at 7:39:58 PM

An FPE breaker for those panels are not very expensive, under $100 and have been noted for years to be very weak. I've even seen a 15 amp carry 40 amps for 5-10 minues and then it didn't even trip, it burnt... Not the best panels.

You might want to hire someone sooner than later to get it changed. Strange that it tripped so easily, must be faulty. Better to trip prematurely than to not and cause a fire though!

An ESA permit, hydro disconnect/reconnect, service call fee and breaker price should cover it. One thing that should be checked primarily is the grounding and bonding cables on the water main and gas pipes.

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Date/Time3/5/2013 at 1:40:46 PM

Very good advice from Ivan and robert.

If it was my home or a cleint of mine, I would have one of my sub's in to inspect. Run the capacity and load tests. And then change out the board.

Don't go for a quick fix, buying another main breaker for the short term.

Good luck with it.

James Fram

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Date/Time3/5/2013 at 7:03:48 PM

Hi Boris

You mention that it is a 125Amp panel, but what size is the main breaker? I tried to zoom in on the picture but I still could not tell.

FPE panels have a bad reputation in the USA, but that is not the case here in Canada. Having said that, they don't make them anymore although you still can get replacement breakers for them.

I still would consider a load calculation to see what size service you need.

Cheers

John

John Kuehnl-Cadwell

Master Electrician

Datawise Solutions Inc

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Boris in Brampton
Date/Time3/5/2013 at 7:42:58 PM

Robert: that's a lot of good info. I think 125A might be enough for this house so hopefully it is just the breaker that needs replacing. Is the service call fee pertaining to the hydro company or electrical contractor?

John: The main breaker looks to be 100A (see photo).

In general, is it common practice for a contractor to charge for going to a home and inspecting the problem and providing a quote?


Main breaker trips when large appliances are on simultaneously
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Robert from Electrilight Ltd. in Oakville
Date/Time3/5/2013 at 9:12:16 PM

Normally a 100amp breaker will easily hold your stove, dryer and AC running without any troubles. If you have fewer than that running and the problem still arises, I would request some testing being done to ensure it is not something deeper than a main breaker. If your main is tripping it means it is faulty or the load is drawing more than your breaker will hold or a combination of the two.

The prices I offered were for a contractor to go out and look, the permit fee would take care of the disconnect and reconnect by the hydro but needs to be done by a licensed ESA contractor.

This sounds more than a "stop-in" visit for a quote but some work needing done to give an accurate assessment of the hazards or troubles. A service call would cost $110-$150 but well worth it. If the calculations are done and the items other than the breaker are found fine, only the breaker needs replacing.

A permit is not required as it is a swap piece for piece, but hydro should be involved to make it safe for everyone.

If you want to upgrade your panel to a 125 or 150, more costs are involved to replace main wires, possibly conduit, meterbase, mast stack, etc if it is overhead. Underground may require more if it is fed from 100a service line in which case the underground would need replacing. But I am sure this is not needed. Not knowing the sq ft of your home, most of <4000 sq ft are running 100amp not problem.

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Date/Time3/8/2013 at 1:40:07 PM

Hi Robert

You might know better than me on this one, but I think an inspection / permit would be required to swap main breaker. Rule 2-005 likely because it is over 50 amps 250v, but even if that does not apply, I am not sure the utility will reconnect without notification from ESA as you are repairing the service equipment.

Cheers

John

John Kuehnl-Cadwell

Master Electrician

Datawise Solutions Inc

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Robert from Electrilight Ltd. in Oakville
Date/Time7/24/2015 at 12:39:20 PM

Absolutely correct John, The permit would be required by OESC code, but knowing how people are trying to save a buck, the job will probably be done without permit or re-inspection. For the record, I advised only, job was done by someone else I assume ;) , a long time ago.

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