Breaker tripping

[GreenEnvy22]

I'm brewing in my garage, and the line coming into the garage is 12 gauge, so I'm limited to 20 amps on each leg.
The wire comes into the garage, and then the red and black side each go into a 20 amp resettable fuse, then to a cutoff switch, and then into the breaker panel.

I have a GFCI 20 amp breaker that runs my element.

Earlier today I had it running at 62% power, so around 15 amps for a few hours, with no issues.

Then this evening I was running it again at 42%, which is about 11.4 amps. After about an hour I turned it up to 45%, which was about 12 amps, and one of the resettable fuses kept tripping.
There isn't anything else on that side of the circuit, the red wire, which is the one tripping, only goes to the element plug.

I stuck my induction amp meter into the cutoff panel, over the red wire, and confirmed it is pulling 12 amps, so nothing else seems to be draining power anywhere.

I've already replaced that resettable fuse because it was doing it before as well last year.

Is it possible that just the multiple hours running between 11 and 12 amps could cause a 20 amp resettable to trip? I would think I'd have to be more around 75 or 80% of its load for that. I also don't know why the black side is never tripping, it has two fridges and the garage lights running off of it.

 

[Bobby_M]

Sounds like the resettable fuse is junk.

 

[augiedoggy]

What size element do you have? is this 240v or 120v? do you have an ammeter installed? with 12awg you are limited to a TOTAL of 20 amps are you splitting us a single 3 conductor+ ground 12awg romex line to run multiple 120v circuits here? are they sharing the same neutral wire? (if so thats your problem as its also only capable of a max of 20a not 40a total from both hot legs used as separate circuits.)

Are you using PWM to control the element? if so that really just pulses the full power draw on and off at different speeds so while it does normally allow the circuit breaker and wiring to stay cool enough to work without problems its not exactly as precise and linear as far as power draw as one might think... It could be the resettable fuse, could also be a poor connection or loose connection somewhere

 

[GreenEnvy22]

240V 4500W element, obviously not running it at that high of a wattage. Voltage is 240V to the PCR based power controller (10,000W controller for margins, with a fan cooling it. The wiring comin into the garage has red, black, and white wires. The ground is a strip in the metal flexible jacket (1970's construction).

Like I said, nothing else is running on the red side, which is the breaker that is tripping. The black side does have other devices on it, but oddly it never trips.

The controller has it's own induction based ammeter, which I'm verifying with a handheld one at the breaker panel itself.

Yes, I know I'm limited to 240V 20A total right now, but when was tripping yesterday, there was still under 15A total in use between the kettle and the rest of the stuff in the garage. It's weird because earlier in the day I was pulling 15A just on the kettle, plus whatever else in the garage (on black leg), with no issues.

I ended up pointing a fan at the problematic breaker so I could finish my boil last night, and it didn't trip again.
Long term the plan is to replace the 12 gauge wiring with 8 or 10, but it will involve cutting up the concrete patio between the house and garage and digging down below frost line to run a new one. I'll also be running water, drain, and natural gas when I do that.
In the meantime I may replace that whole cutoff panel.

 

[augiedoggy]

240V 4500W element, obviously not running it at that high of a wattage. Voltage is 240V to the PCR based power controller (10,000W controller for margins, with a fan cooling it. The wiring comin into the garage has red, black, and white wires. The ground is a strip in the metal flexible jacket (1970's construction).

Like I said, nothing else is running on the red side, which is the breaker that is tripping. The black side does have other devices on it, but oddly it never trips.

The controller has it's own induction based ammeter, which I'm verifying with a handheld one at the breaker panel itself.

Yes, I know I'm limited to 240V 20A total right now, but when was tripping yesterday, there was still under 15A total in use between the kettle and the rest of the stuff in the garage. It's weird because earlier in the day I was pulling 15A just on the kettle, plus whatever else in the garage (on black leg), with no issues.

I ended up pointing a fan at the problematic breaker so I could finish my boil last night, and it didn't trip again.
Long term the plan is to replace the 12 gauge wiring with 8 or 10, but it will involve cutting up the concrete patio between the house and garage and digging down below frost line to run a new one. I'll also be running water, drain, and natural gas when I do that.
In the meantime I may replace that whole cutoff panel.

so are you running the 240v 4500w element at 120v (the red is 120v and black is 120v with the white being the neutral)

Or are you are running it wired to the red and black at 240v while also trying to have other 120v devices drawing additional amperage off the black leg at the same time? If you have stuff like the fridge you mentioned also powered off this same romex than that is your issue as the fridge likely draws 12-14 amps or so by itself when the fridge kicks on (compressor runs when it needs to causing large load swing) leaving you only about 6- 8 amps to spare for anything else (that means only 6-8 amps max at that time on a 240v cricuit using that leg too). You have only a MAX or 20a on each wire whether your powering 120 or 240 or a combo of both. and even at 20a the breaker will often eventually overheat and pop if its a sustained load. try inplugging everything else that runs off that black wire and measure your current draw then... a 4400w element at full power should draw around 16-17 amps at 100% with actual 240v.... not sure what a PCR controller is but many are not linear. like I mentioned a pwm controller powering this element at 50% power would draw 17 amps for the short half second its on and nothing for the other half second which tricks many amp meters into seeing 7-10 amps but its not really the case. I think maybe the wiring for the black vs red is swapped around somewhere and you didnt catch it.. either that or the breaker is just bad.

 

[10_degrees_play-doh]

Let me see if I have this straight... You have a 20A 2 pole breaker in the main panel feeding your garage, going to 2 20A push button breakers / resettable fuses (presumably in their own enclosure?), then going to a local disconnect 240V switch, then going to a breaker panel, with a few breakers/circuits coming out of there to feed your lighting and receptacles in the garage? Why the separate overload protection on the feeder cable in the garage? Even if it's a main lug panel vice main breaker, I think having the local disconnect would satisfy code, though I'm not positive(haha electrical joke). Is it possible the red and black change over in the local disconnect or that you followed the wrong tabs in the breaker panel and it's actually the red lead in the feeder cable that's powering the other circuits? Maybe verify with your ammeter with the brew setup off and the fridge on that it is in fact the black lead feeding those?

 

[10_degrees_play-doh]

never mind, I guess if that stuff is still running with the fuse popped, then they're on the other leg...

 

[IslandLizard]

Sounds like the resettable fuse is junk.

Aside from that, is there any 120V source pulling current from one of the legs? Like a pump, a light bulb, or even a thermostat? That would cause the GFCI to detect an imbalance between the 2 phase leads and trip.

Or you've got a (small) current leak to ground somewhere.

 

[augiedoggy]

Aside from that, is there any 120V source pulling current from one of the legs? Like a pump, a light bulb, or even a thermostat? That would cause the GFCI to detect an imbalance between the 2 phase leads and trip.

Or you've got a (small) current leak to ground somewhere.

I have never had this problem myself..both my panels have different 120v items running off one leg or the other and ive never had the gfcis trip from this although Ive read its possible.

I know some items such as old fridged and appliances can cause gfci breakers to trip but My understanding here is the "resettable fuse"-aka breaker is just overheating and tripping. which is why the fan helps... could be a worn out breaker or could be too much current. I think too much current with the whole garage running off this single circuit.

 

[10_degrees_play-doh]

You could try stripping back to fresh copper for the connection to your resettable fuse(s)- could be that connection building up more heat than it's supposed to. You could also use an antioxidant compound like Noalox. There are some made specifically for copper to copper connections. The bottle I have makes no such distinction and there seems to be some debate on whether you have to use explicitly formulated stuff for copper to copper or whether Noalox is suitable for both, so I'll let you make your own decision on that...

 

[GreenEnvy22]

I am running the boiler element at 240 volt. There are all four wires going to my controller from the GFCI breaker. then from the controller there is just the red the black and the ground, no neutral, to the element. There is nothing else running from that GFCI breaker, and that breaker is not ever tripping.

And yeah, since the fridge and my lights all stay on, I know I don't have my wires mixed up anywhere, they all keep running fine.

As for why there is a separate cut off panel in the garage, I can't say, it was that way when we bought the house, and it's 50-ish years old. I will say it's more convenient to be able to reset the breaker in the garage rather than having to go down into the basement of the house. However the 20 amp fuses in the house have never tripped.

Found some photos of the cutoff, and the breaker panel before I added the GFCI.

 

[10_degrees_play-doh]

I'm thinking there might be some arc damage to that switch from turning it on with a load- looking at that bottom right switch contact visible in the picture. Maybe for the lowest investment solution, shut it off in the house, bring out a light, and go at it with some contact cleaner? Maybe check continuity before and after to see if it's gone down (less resistance, less heat)? Otherwise, you could look at replacing that box with a more modern one such as an a/c disconnect and swapping the 30A fuses with 20A... Might get away with a similar size that way. From what I found from a brief search on the ol' Google for the code requirements for an outbuilding subpanel, since that load center has less than 6 breakers, you shouldn't need a main breaker or local disconnect. Confirm for yourself, but that tells me you could probably technically just splice the line to the load in that disconnect panel and not break any rules. Likewise, I think a 240V lightswitch style switch would also be acceptable, albeit annoying to fill that space and probably requiring an additional junction box to make up for cable length. I know you like having the breakers pop in that panel before the house, but in theory since it's the same current rating then either one could trip just as easily as the other. One more thought: could it be that the breaker that is tripping is operating correctly, and the one that is not is malfunctioning? Perhaps not, as indicated by your ammeter and since the house breaker didn't trip, but food for thought anyway...

Sorry for the lengthy reply, hopefully helpful though. Good luck!

 

[GreenEnvy22]

I'm thinking there might be some arc damage to that switch from turning it on with a load- looking at that bottom right switch contact visible in the picture. Maybe for the lowest investment solution, shut it off in the house, bring out a light, and go at it with some contact cleaner? Maybe check continuity before and after to see if it's gone down (less resistance, less heat)? Otherwise, you could look at replacing that box with a more modern one such as an a/c disconnect and swapping the 30A fuses with 20A... Might get away with a similar size that way. From what I found from a brief search on the ol' Google for the code requirements for an outbuilding subpanel, since that load center has less than 6 breakers, you shouldn't need a main breaker or local disconnect. Confirm for yourself, but that tells me you could probably technically just splice the line to the load in that disconnect panel and not break any rules. Likewise, I think a 240V lightswitch style switch would also be acceptable, albeit annoying to fill that space and probably requiring an additional junction box to make up for cable length. I know you like having the breakers pop in that panel before the house, but in theory since it's the same current rating then either one could trip just as easily as the other. One more thought: could it be that the breaker that is tripping is operating correctly, and the one that is not is malfunctioning? Perhaps not, as indicated by your ammeter and since the house breaker didn't trip, but food for thought anyway...

Sorry for the lengthy reply, hopefully helpful though. Good luck!

Thanks, some interesting things to check out.

 

[thefigure5]

I stuck my induction amp meter into the cutoff panel, over the red wire, and confirmed it is pulling 12 amps, so nothing else seems to be draining power anywhere.

What does this white wire connect to in the cutoff panel?

 

[augiedoggy]

Yeah im super confused... I see no 240v breakers shown and what I do see is red wires connected to black wires with electrical tape and red wires that look like they are taped to more red wires... that does not make for a solid good safe conduction connection at all. keep in mind with every addtional fuse box or even break in the wire and connection point your ability to carry current has the potential to be diminished.

My house is well over a 150 years old so im no stranger to ancient patchwork wiring but If I were you I would eliminate any small pieced together sections of wire if thats in fact what im seeing there. I know you have a seperate 240gfci breaker box but where are those wires feeding it connected in your other panel?
at the very least replace the electrical tape with wirenuts.

 

[10_degrees_play-doh]

Augiedoggy, OP mentioned that picture was before adding the 240V breaker. I was also a bit confused until I re-read that... And yeah, those splices could stand to be cleaned up... Could be proper soldered Western Union splices under there, but if that's the case splice tape or shrink would be more appropriate, and probably some phase tape at the connection point would reduce confusion. Probably not causing the issue he's seeing, though.

 

[doug293cz]

... And yeah, those splices could stand to be cleaned up... Could be proper soldered Western Union splices under there, but if that's the case splice tape or shrink would be more appropriate, and probably some phase tape at the connection point would reduce confusion. ...

Western Union or Western Electric ?

Brew on

 

[10_degrees_play-doh]

Hmm... Telegrams or telephones? The battle to be the Best Western? Something to do with Alexander Graham Bell, inventor of the phone?

https://en.wikipedia.org/wiki/Western_Union_splice

 

[day_trippr]

That's reminiscent of a blood knot and probably shows the same linear strength characteristics. My dad taught me both
Aaaand I once got verbally assaulted on one of my summer jobs while still in school for using that splice because "it takes too long" compared to just slapping wire ends side-by-side and giving them three or four twists. Of course, one of those splices is easily taped - and it isn't the "slapped" splice

Cheers!