# Heater blowing circuit breaker?



## Richard M (Apr 16, 2016)

I have an Eheim 300W heater; this week, the circuit breaker on the power outlet circuit in the main powerboard has blown twice.

The aquarium is in my home office (I work from home), so on both occasions, I noticed straight away as my PC screen dimmed and lights/pumps etc went out in the tank.

When I reset the breaker, I noticed each time that the heater was on (light visible); I'm wondering if a fault in the heater could do this as the thermostat clicks on?

The unit came second hand, with the tank, so it isn't new.

Any ideas?


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## Narwhal72 (Sep 26, 2006)

Circuit breakers trip when overloaded. I.E. the Amperage is higher than the rated amperage of the breaker. A 300 watt 220V heater will be drawing 1.36 amps. You may want to see what all is plugged into that circuit to see if you are drawing more than what is rated for the breaker (it should be marked on the breaker switch). It could be that when the heater is activated, the combined amperage of all the devices on the circuit is higher than the allowable amperage for the breaker and causing it to trip.

If your breaker is also a GFCI or AFCI breaker it could trip if it detects a leak of power to ground or an arc. In which case, the heater is leaking and bad and should be discarded.

Andy


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## tanker3 (May 18, 2015)

What else to you have on that power strip?


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## Narwhal72 (Sep 26, 2006)

Not just the power strip. What is all on that circuit? You mentioned that your PC dimmed. That should only happen if your PC is on the same circuit as the heater (and also has a battery backup otherwise it would have just shut off). Flip the breaker off and log all the devices that turn off when you do. Then check the amperage of each device (it may be listed on the product label).


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## Richard M (Apr 16, 2016)

I have 3 double socket electrical outlets - I don't run anything off extension leads, each unit is plugged direct into its own wall socket, I had a new one installed specifically for the aquarium; the whole house has a single power socket circuit breaker (as distinct from hot water, air con, oven and stove top which are all on their own breakers; our power is 240V AC.

The aquarium loading is

Canister filter - 25W 0.1A

LED light - 24W 0.1A

Wavemaker - 3W 0.0125A

Heater - 300W 1.25A

Only other stuff that's on during the day is microwave, DVD player and LED TV (on standby), modem-router for phone & internet fibre-optic connection refrigerator and chest freezer.


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## Richard M (Apr 16, 2016)

Narwhal72 said:


> Circuit breakers trip when overloaded. I.E. the Amperage is higher than the rated amperage of the breaker. A 300 watt 220V heater will be drawing 1.36 amps. You may want to see what all is plugged into that circuit to see if you are drawing more than what is rated for the breaker (it should be marked on the breaker switch). It could be that when the heater is activated, the combined amperage of all the devices on the circuit is higher than the allowable amperage for the breaker and causing it to trip.
> 
> If your breaker is also a GFCI or AFCI breaker it could trip if it detects a leak of power to ground or an arc. In which case, the heater is leaking and bad and should be discarded.
> 
> Andy


Yeah - we call them Residual Current Devices and that's what it is. The RCD unit is rated to 40A but trips out at 30mA earth leakage.

Looks like it's a new heater then - this is the only device that is switching on/off so I reckon that's it.

Also just noticed some condensation inside the heater tube too.


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## Narwhal72 (Sep 26, 2006)

Some condensation is normal inside heaters. When you see a lot like you see in your heater that's a problem and indication of a leak. The leaking current will then cause your breaker to trip if it is a GFCI and [there is an alternate ground path]. (moderator edit based on discussion below)

Interesting that your outlets are on one breaker for the whole house.


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## dledinger (Mar 20, 2013)

I suspect that heater probably has a direct short causing an immediate overload.

Circuit breakers are inverse time. The higher you go over rated capacity the faster they trip. If it trips instantly when the heater comes on, that is likely a direct short.

FWIW, a leaky heater wouldn't necessarily trip a GFCI. In fact, I think that would be very unlikely unless you've deliberately grounded your tank somehow.


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## dledinger (Mar 20, 2013)

To add..."deliberately grounding" would include putting an arm into a tank. Any situation that would create an _alternate_ path to ground. Under normal aquarium conditions, having only a neutral and a hot in a tank, any current between them is a short. Current between those 2 conductors - no matter how much - would still result in balanced hot-neutral currents and fail to create the unbalanced conditions that is actually what a GFCI detects.

I say all this because a leaky heater, even if not tripping a GFCI, is still dangerous.


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## Narwhal72 (Sep 26, 2006)

Yes. you would need to have an alternate ground path for the GFCI to trip.

General utility pumps tend to be grounded nowadays because of cUL requirements for that category. Unless you have a sump you probably don't have one. Most filters, heaters, and lights (unless they have a metal housing) do not have a three prong ground plug.

Andy


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## dledinger (Mar 20, 2013)

I guess this is where the electrical nerds hangout. So glad I retired, but I still can recite the theory of operation for a florescent lamp in my sleep. I'll admit, too, that sometimes I read 1960s code books for fun. In 2017, even though it will serve no purpose, I'll add another just so I can continue to nitpick the NFPA.


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## Richard M (Apr 16, 2016)

It's pretty well sorted, or soon will be - new heaters on order.

I'm going to fit 2, with one as a backup.


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## SrsSarcasM (Jan 28, 2016)

It's worth getting a local portable RCD exclusively for the tank and then putting just the heater on it - if it trips off the RCD then you'll know it is the heater.


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## dledinger (Mar 20, 2013)

No, that won't work.

That's why I politely pointed out that Narhwal has spread misinformation about GFCIs (interestingly he replied agreeing with me as if I asked his approval )


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## Narwhal72 (Sep 26, 2006)

No dledinger I was not seeking your approval. Just not afraid to admit when I am wrong.


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## dledinger (Mar 20, 2013)

That's not what I said, Narwhal, but you should note the little smiley face in my post....I was jesting with you.

As far as the GFCI I think this is very important to note. One could falsely conclude that a faulty heater(or any other equipment) is safe if it doesn't trip a GFCI, put it in another tank, ground it with their body and die. The potential implications of this error are not small.

Anyway you want to look at it, this is a good discussion about GFCIs and very fitting to an aquarium forum.


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## Kanorin (Apr 8, 2008)

dledinger said:


> That's not what I said, Narwhal, but you should note the little smiley face in my post....I was jesting with you.
> 
> As far as the GFCI I think this is very important to note. One could falsely conclude that a faulty heater(or any other equipment) is safe if it doesn't trip a GFCI, put it in another tank, ground it with their body and die. The potential implications of this error are not small.
> 
> Anyway you want to look at it, this is a good discussion about GFCIs and very fitting to an aquarium forum.


Narwhal's post on the previous page has been slightly edited so that readers would not "falsely conclude" anything in regards to matters of safety. I'll keep this thread open so long as the posting stays civil :thumb: .


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## dledinger (Mar 20, 2013)

I saw that, Kanorin, and it reads perfectly. Thanks.


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## Narwhal72 (Sep 26, 2006)

No worries dledinger. What I said in the other post about loss of tone in a conversation is responsible for that one.


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## dledinger (Mar 20, 2013)

I'm hoping the OP will pop back in and let us know how everything worked out for him. Diagnosing a fault over the internet isn't an easy thing to do...and I hope it's been correctly ID'd as the heater.


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