2250watt element tripping 20 amp breaker

[Jbrew]

I tried searching this on google but didn’t find too much. I wasn’t really sure the proper wording for asking it. If its been answered before I’m very sorry.
Here’s what I have going on. Built a 120v 20 amp control panel, running a 2250watt tri clamp element off of it. Just finished the build and did a water test Saturday. Started with hot water out of the tap at about 120* F. Took about 15 minutes to bring it up to 142* at which point I put it into auto tune which took another 20 minutes or so for it to complete and leveled off at 152 which I set the PID for. I then Put it in manual mode at 100% to bring it to a boil. About 40 minutes later the breaker tripped with water temp at about 200*. I flicked it back on And set it to 90% to get to a boil. It went another 40 minutes or so and then My fuse holder began to distort from heat that I installed in the brewery panel.

So here’s my concerns:
I had a 20 amp agc glass fuse installed, the wire and fuse holder got hot enough to melt the plastic holder. I have this wired from the 120v input to the ssr load input. The ssr output to the outlet for the heating element never got hotter then Luke warm. Its distorted to the point that it no longer makes contact so I cannot take resistance readings of it, but I’m guessing that the fuse holder created too much of a voltage drop. I will admit, the fuse holder was something I had laying around. It is 12 gauge, but I think it might be rated for automotive use, ie. Low voltage DC. Bad idea using it. I’m assuming I can go without a fuse on the element load circuit as the breaker should trip if it pulls too much. I’ve seen a few brewery control panel build diagrams with and without fuses/breakers in them

I know that the 2250 watt element is above the 80% capacity of the circuit pulling about 18.75 amps, but the 10g 120v boil coil is the same wattage and rated for a 20 amp circuit. NEC I believe says that a breaker is only rated to handle 80% of its rating for continuous load and that a load shall not exceed 80% of the circuits rating.
Anyone here running a 20 amp setup without any issues? I guess between the breaker tripping, the melted fuse holder and running up to 19 amps continuously for possibly an hour or more for heat up makes me pretty nervous. I just picture the wiring in my walls just lighting up.
Thanks all for the advise.

 

[BeerBaron1985]

I got the same triclamp element, and will be doing testing soon in the next few days for my small E-Extract system. IMO there is no need to put a fuse in your control panel. The CB in your breaker panel and a proper gfci plug or breaker is adequate. I have a 25A switch that I can ise to disconnect everything in case of emergency. Im running all 10AWG. No 12AWG with the exception of whats in the wall.

If I have the same trouble ill let you know.

 

[processhead]

Not sure what the age of your panel is, but not a surprise if an older breaker running at close to the rated amperage is tripping prematurely. Breakers do fail with age and use.

I would definitely ditch the small automotive fuse holder. Those small fuses are OK for control voltage for instruments and light loads in your panel, but not what you want for the power loads like heating elements.

 

[BeerBaron1985]

Agreed. Even the Push To Reset Thermal breakers like what you find in generators are only rated 80% continuous. And something like 120% rating for 15 minutes or something like that.

Ill be doing a video on my E-Extract setup soon. Same 2250 element. 40A SSVR with dial pot, 3 pole B-B-M type, element indicator light, and voltage/current/wattage/frequency meter. Got a 20A 12AWG 120V GFCI plug on my kitchen island. Excited to see how it works!

 

[Jbrew]

My house is pretty old, but the panel was upgraded in the earlier 2000s and the wiring was replaced. Its a square d qo breaker. I’m running a 20 amp gfci outlet. Nothing else is on the circuit except the stove, which is a gas range, and a tv that’s in the kitchen. I did have the tv on at the time, which when I looked up should pull another 55 watts or so. So I guess maybe an additional half an amp. That could of put it over I guess.
The part that kind of scares me, is that it’s pulling more then 80% of the circuit capacity for likely an hour or more. I know 12 gauge wire is rated for 20 amp, but I can’t seem to find how much current 12 gauge wire handles before it’ll start heat up and fail.

 

[BeerBaron1985]

You would have to check the type of 12AWG wire installed. It should have the letter code on the insulation jacket. Most common is the 60C variety. Anything higher is actually better.

 

[Jbrew]

Understood. But without sounding like a moron what is that table saying? If its rated for 60c it’s only capable of 20 amp max? Is that what it’s saying?

 

[BeerBaron1985]

Exactly. Copper conductor (not aluminum) 12AWG thats type TW or UF is rated up to 60C and 20A before the insulation goes beyond its rated temp, then is at risk for failing.

Most HD or Lowes romex you buy like 12/3 is UF rated. Thats what I have.

Southwire 25 ft. 12/3 Gray Solid CU UF-B W/G Wire
https://www.homedepot.com/p/Southwire-25-ft-12-3-Gray-Solid-CU-UF-B-W-G-Wire-13058321/301369855

 

[Jbrew]

I haven’t gone down to the basement to look, but I know it’s romex which is considered UF or NMC, so I’m sure it’s rated for 60*C. I replaced the input line where the fuse holder was with another piece of 12 gauge, and re tested tonight. All the wiring stayed much cooler and the breaker did not trip. I do feel a little better after tonight’s test.
But still I have to ask, anybody using a 2250 watt element on a 20amp circuit feel comfortable about it? Pulling that much current so close to the rated capacity still makes me a bit uneasy.

 

[BeerBaron1985]

I haven’t gone down to the basement to look, but I know it’s romex which is considered UF or NMC, so I’m sure it’s rated for 60*C. I replaced the input line where the fuse holder was with another piece of 12 gauge, and re tested tonight. All the wiring stayed much cooler and the breaker did not trip. I do feel a little better after tonight’s test.
But still I have to ask, anybody using a 2250 watt element on a 20amp circuit? Pulling current so close to the rated capacity still makes me a bit uneasy.

Give me till this weekend and I can report back to you. Got all my parts delivered and some assembly required lol.

 

[doug293cz]

As long as you are not running for more than 3 hours @ 100%, you should be ok. Lots of brewers run close to the breaker limits without issues. You can probably dial back from 100% after your wort starts to boil. You don't actually need a roiling pot - a gentle boil is more than sufficient. The most likely place for heat issues to arise is at connections. If you have an IR thermometer, you can check for excessive heat near connection points. The outlet and inside the breaker panel would be good spots to check.

Brew on

 

[BeerBaron1985]

Make sure those crip connections are solid!

 

[Jbrew]

I have only a couple of crimp connections, at the relay and I’m pretty sure there right, but I’ll give I’m a once over to be sure. Doug, its good to hear that it can be fairly common practice for others to do it as well.
Once it got up to boil i dialed it back to 80%. I think that’s as much I can go, it was a pretty soft boil at 80%. But it’ll at least do it.
Thanks all for the advice so far.

 

[processhead]

I don't think your 12 AWG wiring is an issue here. Loose connections create resistance and heat but doesn't increase the current in the circuit. You will certainly want to find and correct any loose connections if they are out there. But for $8 you can replace the breaker and rule that out as a point of failure.

 

[Jbrew]

I don't think your 12 AWG wiring is an issue here. Loose connections create resistance and heat but doesn't increase the current in the circuit. For $8 you can replace the breaker and rule that out as a point of failure.

I think I will. I also had a small led tv on, on the same circuit during the first test, so that could’ve pushed it over as well.

 

[processhead]

Measuring the actual amp draw in an AC circuit requires a clamp on ammeter, which most folks don't have lying around in their tool boxes.

Short of that, you are left having to calculate amp draw based on published specifications of individual loads. Even that calculated load assumes everything is working correctly. If there are malfunctions with the loads, or faults within the system, actual amp draw can be higher than the calculated amp draw.

 

[Soulshine2]

I tried searching this on google but didn’t find too much. I wasn’t really sure the proper wording for asking it. If its been answered before I’m very sorry.
Here’s what I have going on. Built a 120v 20 amp control panel, running a 2250watt tri clamp element off of it. Just finished the build and did a water test Saturday. Started with hot water out of the tap at about 120* F. Took about 15 minutes to bring it up to 142* at which point I put it into auto tune which took another 20 minutes or so for it to complete and leveled off at 152 which I set the PID for. I then Put it in manual mode at 100% to bring it to a boil. About 40 minutes later the breaker tripped with water temp at about 200*. I flicked it back on And set it to 90% to get to a boil. It went another 40 minutes or so and then My fuse holder began to distort from heat that I installed in the brewery panel.

So here’s my concerns:
I had a 20 amp agc glass fuse installed, the wire and fuse holder got hot enough to melt the plastic holder. I have this wired from the 120v input to the ssr load input. The ssr output to the outlet for the heating element never got hotter then Luke warm. Its distorted to the point that it no longer makes contact so I cannot take resistance readings of it, but I’m guessing that the fuse holder created too much of a voltage drop. I will admit, the fuse holder was something I had laying around. It is 12 gauge, but I think it might be rated for automotive use, ie. Low voltage DC. Bad idea using it. I’m assuming I can go without a fuse on the element load circuit as the breaker should trip if it pulls too much. I’ve seen a few brewery control panel build diagrams with and without fuses/breakers in them

I know that the 2250 watt element is above the 80% capacity of the circuit pulling about 18.75 amps, but the 10g 120v boil coil is the same wattage and rated for a 20 amp circuit. NEC I believe says that a breaker is only rated to handle 80% of its rating for continuous load and that a load shall not exceed 80% of the circuits rating.
Anyone here running a 20 amp setup without any issues? I guess between the breaker tripping, the melted fuse holder and running up to 19 amps continuously for possibly an hour or more for heat up makes me pretty nervous. I just picture the wiring in my walls just lighting up.
Thanks all for the advise.

I'm going to start by stating that I am not an electrician but I'm pretty sure the automotive fuse holders are not meant to have more than 12 volts running through them. Your 120v/20 amp system I think should be 10 gauge wire ,not 12. There is resistance somewhere creating the heat melting your fuse holder. You should have a GFCI somewhere in your brewing system,whether it is a breaker or outlet. It would be a good idea to check with a licensed electrician before you proceed.

 

[processhead]

AGC type fuse holders vary all over the place in construction. Just because a 20 amp AGC fuse will fit in the holder does not necessarily mean the holder is constructed to handle the sustained current through the holder over time.

The fact that the fuse holder melted suggests that the mechanical contacts or connections to the holder had internal resistance.

Compounding the problem with resistance induced heat rise in a mechanical connection is oxidation and expansion that takes place at the connection site. Expansion and oxidation usually causes the resistance to increase even more. Its just a death spiral after that until the connection burns loose and opens the circuit.

As long as the load current remains below the trip rating of the panel breaker, the breaker won't protect against this type of failure unless something grounds-out during all the heating and melting in the brew panel.

All of the above is why when constructing a brew panel it is important to use the correct materials and assemble it with the proper methods and workmanship.

 

[itsnotrequired]

I haven’t gone down to the basement to look, but I know it’s romex which is considered UF or NMC, so I’m sure it’s rated for 60*C. I replaced the input line where the fuse holder was with another piece of 12 gauge, and re tested tonight. All the wiring stayed much cooler and the breaker did not trip. I do feel a little better after tonight’s test.
But still I have to ask, anybody using a 2250 watt element on a 20amp circuit feel comfortable about it? Pulling that much current so close to the rated capacity still makes me a bit uneasy.

i wouldn't sweat the cable, unless it is visibly damaged or something like that. modern (mid-1980s and later) nm (technically nm-b) cable is constructed to operate at up to 90 degree C so pushing 30 amps through a #12 is not an issue. that being said, nec rules limit the allowable ampacity to those values identified in the 60 degree c column (20 amps). basically, the cable runs 'cooler' that its capability or in other words, is 'beefier' than it needs to be.

 

[Jbrew]

I do have a clamp ammeter, I took a few readings while operating the controller. The element was pulling roughly 17 amps. It is a fluke meter but it’s resolution isn’t anymore then a tenth of an amp. I also installed a volt/ammeter on the panel. During full tilt running with the pump recirculating the meter on the panel read 18 amps, however I cannot be certain this is 100% accurate. It was a cheaper amazon meter.

I don’t know that I would need 10 gauge inside the actual brewery panel. 12 gauge is rated for 20 amps. I believe the resistance itself was inside the fuse holder. It was just a plastic case with a glass fuse inside and 2 small contacts held against the fuse ends with springs. I am using a 20amp gfci outlet.
I should also say that I didn’t expect the breaker to trip because of the faulty fuse holder. The fuse holder only Scared me to realize that 20 amps is a lot of current. I’m aware that my fuse holder was a poor decision as it’s specifications of what its meant for are unknown. I originally had plans to go without a fuse holder on the element load circuit anyway as the circuit breaker down at the service panel should trip if the element were to pull too much, but I then found a different panel diagram online in which they did add a fuse. At that point I figured what could it hurt adding an additional fuse. The entire brew panel was constructed using items rated for 20amp service or greater. It currently uses a 40amp ssr, with a 30 amp relay controlled by a 3 way NO/NC switch and an e stop NC switch. With the exception of the fuse holder which I Stupidly decided to use, the entire build was designed for the planned voltage and current.

My main reason for posting this thread wasn’t so much the fuse holder melted. As I said the fuse holder melting just reminded of how much current the heating element will be pulling, and how serious it could be should it overcurrent and the breaker fail to protect the wiring.
My main concern was that using A 2250watt element pulls well beyond 80% of the circuits rated capacity and as per electric code, a load should not pull greater then 80% of the circuit.
When it comes down to it, this is a home built device pulling 95% of the circuits capacity that it was built for and running continuous for an hour or more at a time. Obviously it is not a UL rated device, and certainly could come into question if something were to happen. It makes me a bit uneasy and I was looking to see if anyone can confirm that it’s “normal” or “ok” for a 20amp homebrew system to operate this close to the edge. Unfortunately there doesn’t seem to be to many people brewing on 120v. I apologize for my ramblings and thank you all for the help.

 

[Spartan1979]

What type of fuse holders should we be using in our control boxes? I bought similar ones to protect my pumps and now I'm thinking I purchased the wrong thing.

I was under the impression that if I went from 10 ga wire to 14 ga wire on a 30 amp breaker I would need fuses.

 

[doug293cz]

What type of fuse holders should we be using in our control boxes? I bought similar ones to protect my pumps and now I'm thinking I purchased the wrong thing.

I was under the impression that if I went from 10 ga wire to 14 ga wire on a 30 amp breaker I would need fuses.

Depends on the current rating of the fuse. The contacts of the fuse holder need to be designed and rated to handle that current continuously. For AGC fuses for anything more than about 2A, I would avoid the in-line fuse holders.

Brew on

 

[Jbrew]

i wouldn't sweat the cable, unless it is visibly damaged or something like that. modern (mid-1980s and later) nm (technically nm-b) cable is constructed to operate at up to 90 degree C so pushing 30 amps through a #12 is not an issue. that being said, nec rules limit the allowable ampacity to those values identified in the 60 degree c column (20 amps). basically, the cable runs 'cooler' that its capability or in other words, is 'beefier' than it needs to be.

This was something I had thought too, but I couldn’t seem to find much info on. When I google it, I got the fusing current of 12 gauge at 235 amps and that it is rated for 20 amp, but not much else. I think perhaps my wording isn’t the best when searching. I have no interest in pushing more then 20 amps thru 12 gauge wire, but I still was curious as to what the limits of it are. The table provided says that 12 gauge with 60*c insulation can only handle 20 amps, so does that mean at 21 amp it’ll heat up the insulation to the point of melting it off? At what point is too much current for a 12 gauge wire? This brings me back to the fact that if I’m running on the edge of the circuits capacity, how close to the edge am I to burning something up? I m glad to hear that 12 gauge could handle 30 amp.
Sorry I know I keep beating a dead horse.

I am running a .5 amp glass fuse for the pid as well as a 2 amp for the pump outlet but I’m thinking of swapping them out for the push button breakers.

What type of fuse holders should we be using in our control boxes? I bought similar ones to protect my pumps and now I'm thinking I purchased the wrong thing.

I was under the impression that if I went from 10 ga wire to 14 ga wire on a 30 amp breaker I would need fuses.

 

[itsnotrequired]

This was something I had thought too, but I couldn’t seem to find much info on. When I google it, I got the fusing current of 12 gauge at 235 amps and that it is rated for 20 amp, but not much else. I think perhaps my wording isn’t the best when searching. I have no interest in pushing more then 20 amps thru 12 gauge wire, but I still was curious as to what the limits of it are. The table provided says that 12 gauge with 60*c insulation can only handle 20 amps, so does that mean at 21 amp it’ll heat up the insulation to the point of melting it off? At what point is too much current for a 12 gauge wire? This brings me back to the fact that if I’m running on the edge of the circuits capacity, how close to the edge am I to burning something up? I m glad to hear that 12 gauge could handle 30 amp.
Sorry I know I keep beating a dead horse.

how much current a given copper conductor/cable can adequately carry is a function of the type of insulation and ambient temperature. the copper itself could be glowing hot but as long as the temp does not exceed the insulation temp rating, it will practically be fine (this is pretty funky cable though, stuff in kilns or furnaces). similar for ambient temp, code actually allows you to increase the allowable ampacity a conductor can safely carry, as the cooler surrounding air helps pull heat away (conversely, a conductor in a hot environment has to carry less current). it's all about heat, baby!

as mentioned above, you could push 30 amps through that #12 romex and not risk melting or damaging the cable, it is just that code won't let you push that much through. i wouldn't bat an eye at pushing 20 amps. the real issue here is the circuit breaker and this is why the 'only run 80% of the breaker rating through the circuit for continuous loads' requirement comes from. it isn't that the breaker can't handle the current, its that the prolonged operation at that higher current results in, you guessed it, additional heat around the circuit breaker. just like you need to derate conductor ampacity for higher ambient temps, the same is true with a breaker. higher ambient temps = faster (lower) trip levels. so if you run enough current through the breaker for a long enough time, it could heat up to the point where it would trip, more of a nuisance than anything else. limit to 80% = less heat = 'normal' operation.

for your specific situation, practical concern is nuisance tripping, there isn't any inherent safety issue with your setup. in reality, you would need to have a 'perfect storm' of variables to get to the point where you start tripping a breaker. stuff like high ambient temp in the brew area, other high-amp loads in breakers in the panelboard adding to the overall heat within the panel, etc.

 

[Spartan1979]

Depends on the current rating of the fuse. The contacts of the fuse holder need to be designed and rated to handle that current continuously. For AGC fuses for anything more than about 2A, I would avoid the in-line fuse holders.

Brew on

I'm looking at protecting my pumps which be wired with 14 ga wire with a 30A GFCI in the subpanel. A March pump pulls about 1A (is that right?) So, I was planning on putting a 7.5A fuse in a inline holder. Is this the right solution? What do you recommend for this? Does it matter if the fuse is on the hot side or neutral?

 

[doug293cz]

I'm looking at protecting my pumps which be wired with 14 ga wire with a 30A GFCI in the subpanel. A March pump pulls about 1A (is that right?) So, I was planning on putting a 7.5A fuse in a inline holder. Is this the right solution? What do you recommend for this? Does it matter if the fuse is on the hot side or neutral?

My Chugger is rated at 1.4A, and I assume Marches are about the same. But, a motor is an inductive load, so will draw more current when switched on, but not for long. Thus a 7.5A fuse should work fine, and an in-line holder should be adequate (unless it is really poor quality.) I usually spec out a 10A fuse for pump and aux outlets, but there is nothing written in stone about that.

Fuses should always be placed in the hot line (as should switches, relays, etc.) A fuse in the neutral line will offer no protection if the hot line shorts out.

Brew on

 

[Soulshine2]

What type of fuse holders should we be using in our control boxes? I bought similar ones to protect my pumps and now I'm thinking I purchased the wrong thing.

I was under the impression that if I went from 10 ga wire to 14 ga wire on a 30 amp breaker I would need fuses.

I wouldnt push any more than 15 amps through 14 ga wire. 10ga for 20 amps and 6ga for 30amps (220v)

 

[Spartan1979]

I wouldnt push any more than 15 amps through 14 ga wire. 10ga for 20 amps and 6ga for 30amps (220v)

I'm only using 14 ga for the pumps and to power the RaspberryPi. Only stuff that is 110v. Everything else is 10 ga.

 

[doug293cz]

I wouldnt push any more than 15 amps through 14 ga wire. 10ga for 20 amps and 6ga for 30amps (220v)

What are you basing this on? You are suggesting that the NEC ampacities are not safe enough. You can certainly do what you suggest, without any safety concerns, but according to best available guidance, it is totally unnecessary. Heavier wire is more costly, and harder to work with.

Brew on

 

[Jbrew]

how much current a given copper conductor/cable can adequately carry is a function of the type of insulation and ambient temperature. the copper itself could be glowing hot but as long as the temp does not exceed the insulation temp rating, it will practically be fine (this is pretty funky cable though, stuff in kilns or furnaces). similar for ambient temp, code actually allows you to increase the allowable ampacity a conductor can safely carry, as the cooler surrounding air helps pull heat away (conversely, a conductor in a hot environment has to carry less current). it's all about heat, baby!

as mentioned above, you could push 30 amps through that #12 romex and not risk melting or damaging the cable, it is just that code won't let you push that much through. i wouldn't bat an eye at pushing 20 amps. the real issue here is the circuit breaker and this is why the 'only run 80% of the breaker rating through the circuit for continuous loads' requirement comes from. it isn't that the breaker can't handle the current, its that the prolonged operation at that higher current results in, you guessed it, additional heat around the circuit breaker. just like you need to derate conductor ampacity for higher ambient temps, the same is true with a breaker. higher ambient temps = faster (lower) trip levels. so if you run enough current through the breaker for a long enough time, it could heat up to the point where it would trip, more of a nuisance than anything else. limit to 80% = less heat = 'normal' operation.

for your specific situation, practical concern is nuisance tripping, there isn't any inherent safety issue with your setup. in reality, you would need to have a 'perfect storm' of variables to get to the point where you start tripping a breaker. stuff like high ambient temp in the brew area, other high-amp loads in breakers in the panelboard adding to the overall heat within the panel, etc.

Thank you for your response. This is what I was really looking to hear.
I did a maiden brew yesterday with the system. I ran the boil between 90 and 100% the whole time just to try and maximize boil off as I overestimated grain absorption. My Pv values began to jump around about half way thru the mash and I had a couple overflows during recirc, but I never had a nuisance trip and the entire panel operated cool.

Thank you all for the advice.