I would normally agree with you on the 3 hours or more for a continuous load but we are essentially building water heaters here and they are an exception to that code article. Article 422.13 states that "A fixed storage-type water heater that has a capacity of 120 gal or less shall be considered a continuous load." I realize that most brew systems are portable and this is still an area open for interpretation but there is a reason that these appliances are calculated in this way. I think in our application that running a 5500 watt and 4500 watt element on the same 50 amp circuit will probably not cause nuisance tripping due to heat buildup (or any other problems) but I felt the legality of such an installation should at least be brought up if something happened and an insurance company had to get involved.
2x 4500W elements?
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I'd be curious how the electrical inspectors would weigh in on it. While describing this type of system, I'd certainly start by saying "well you know how an electric water heater works right?" but from an actual real world perspective, they are not being controlled with a simple on/off controller and it's not a single 11KW element. This system is also not being left to its own to run whenever the heat is called for 24/7. The reason a water heater would be considered constant use is that we have no way of knowing how much water will be consumed. As long as a certain threshold of use is reached, that element may be on for hours straight.
I'd be curious how many electric brew system builders have actually permitted and got an inspection on their system. I pulled the permit for doing the 200a service upgrade and the 50 spa panel. I just told the inspector that I wanted the outlet for a future option of running a welder. However, I have no plans of having an inspection done on my brew system.
I'd be curious how many electric brew system builders have actually permitted and got an inspection on their system. I pulled the permit for doing the 200a service upgrade and the 50 spa panel. I just told the inspector that I wanted the outlet for a future option of running a welder. However, I have no plans of having an inspection done on my brew system.
It was just something to consider when building an electric system. The only difference I could see was that we monitor it when it's operating. Other than that it works in exactly the same way albeit with some simpler parts,(bi-metal thermostat and relay controlling two elements vs. pid and ssr controlling one or two elements), but otherwise it's the same stuff. I thank you for making me get out my code book and dig through it for the information. It seems like I don't do that enough any more and am starting to get a little rusty with my knowledge. Hopefully this will allow other builders to make the right choices when they build their own systems.
Getting a permit and inspection is only required for the building wiring. Once that building wiring is in place and terminates in a single drop outlet, all is good to go for the home brewer and the brew controller.
The idea of "nuisance tripping" just boggles my mind. Where does that come from? I'd like to see the factual information about this happenstance.
The idea of "nuisance tripping" just boggles my mind. Where does that come from? I'd like to see the factual information about this happenstance.
Regarding the original question, of whether or not a 50 Amp circuit, wired in 6 AWG is permissible to serve this 37.5 A load; you should have no problems, so long as nothing else is on this circuit. NEC 210.23 Permissible loads states: "An individual branch circuit shall be permitted to supply any load for which it is rated."
In a general purpose branch circuit supplying 2 or more outlets, no one cord and plug connected equipment may exceed 80% of the circuit rating, which I believe is where the original confusion came in?
Individual branch circuits are those which only supply ONE piece of utilization equipment. It can be either fastened in place or end in a single receptacle, such as one of these guys: (though a different design for 50A)
Now as to the topic of derating for continuous use, yjfun makes a very good point with article 422.13, and I think this might come down the the particular AHJ's interpretation of the code. In a basic way, it really is just a water heater by definition, but bobby_m explains the difference pretty well. I may just ask my inspector tomorrow to see what he would say in this situation.
In a general purpose branch circuit supplying 2 or more outlets, no one cord and plug connected equipment may exceed 80% of the circuit rating, which I believe is where the original confusion came in?
Individual branch circuits are those which only supply ONE piece of utilization equipment. It can be either fastened in place or end in a single receptacle, such as one of these guys: (though a different design for 50A)
Now as to the topic of derating for continuous use, yjfun makes a very good point with article 422.13, and I think this might come down the the particular AHJ's interpretation of the code. In a basic way, it really is just a water heater by definition, but bobby_m explains the difference pretty well. I may just ask my inspector tomorrow to see what he would say in this situation.
shroomzofdoom
Well-Known Member
Good point, the building code is only for standard wiring and panels; the building inspector doesn't really see what you connect up to it. Anyone going to go through the trouble of getting their panels UL listed?
I had an master electrician and plumber over and showed him my dual element 120v BK, and asked for his frank assessment on my safety.
As Bobby mentioned, I started out with 'well, you start with a water heater and just replace the tank with a beer keg'
He gave me a gold star for using GFCI outlets, and for adding a grounding lug at the keg skirt. I explained the design concepts around using JB Weld to pot the elements and while he had concerns over the longevity of this due to heat--he agreed that this was about as safe and water proof as any strain relief. He did not like the idea of an outlet on the outside of the kettle at all. This is the same guy that told me he would NEVER come over for brew day if I built heatsticks. He warned me about using electrical cords in wet areas and strongly suggested that I use some squeeze clamps or guides to keep the wires off the counters and floors when brewing.
That said, he still gave me a 20% chance of electrocuting myself. ;-)
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Hey, those are pretty good odds since the chance of 3rd degree burns is probably 22% on any given brew day.
Nuisance tripping is generally caused by heat build up due to a high load on a breaker. A standard 20 amp breaker is designed to run forever with 18 or less amps of draw on it (80%) but it will run for a while with 19.9 amps of load before the heat build up causes it to trip. This is called nuisance tripping when the breaker won't hold the load but isn't technically overloaded or shorting out. Some manufacturers are more prone to this problem than others.
Could somebody explain to me the way the emergency off switch works in the diagram by P-J? if it is being fed 120 VAC, and the switch is closed, wouldnt that cause (120/2000)A to be drawn through those resistors to ground? .06A is what i get which would not blow the fuse but would cause 7.2 watts to dissapate across the two 1kohm, 1 watt resistors. Wouldnt this overheat those two resistors?
Or is it a non-issue becasue the current will only run through that line momentarily until the breaker trips?
Or is it a non-issue becasue the current will only run through that line momentarily until the breaker trips?
EarthBound
Well-Known Member
In the foot notes of the diagram:
Which will only happen for a few milliseconds while the GFCI trips. It is exactly the same as if you press the test button on the GFCI breaker. BTW: at 0.06A of power that is drawn (7.2 watts), do you really think a few milliseconds of that power draw would harm a pair of 1W resistors? Really???
I guess I should quit making diagrams anymore for the brew community.
...
Edit: (deleted) - Nevermind. I will only come out to be understood the wrong way.!
MonkeyWrench
Well-Known Member
I had never thought of intentionally tripping the GFCI for E-stop functions. That's a good idea. I was planning on using a contactor, but this looks like a cheaper/easier method.
Just to let you in on a 'little' of my thinking - When something happens that is somewhat potentially catastrophic, I thing it would be wise to kill all of the power to your brew area. Smoke comes out from 'something'. A relay circuit in your CP does not prevent power from being delivered to it. You trip "your" circuit and smoke continues.
Now what? Run 50' - 100' to the mains panel to cut the breaker. Or run a good distance to pull a plug (dangerous by its self) delivering power to your brewery?
As I said before, I think I'm done....
Well, do you think i would have asked if i didnt find it questionable? Why, when dealing with a cheap component such as a resistor, would you use one that is not rated for at least the amount of current you fully expect it to handle? why not a single 2k 10W resistor?
I know this is not a big deal, but i dont think myself and the rest of this community need our hands slapped for asking a valid question. And by the way, i very much appreciate the diagrams and info that you have given thus far and hope that you will continue to post them!
Go do it your way and, like I said, "I think I'm done.... "
A low power resistor is perfectly fine for this use, do you think the test button in your GFCI outlet uses a big expensive 10W power resistor to do its job? Not a chance. PJ's design looks sound to me.
I do however think that asking questions is the best way to learn.
I do however think that asking questions is the best way to learn.
I wanted to bump this thread and see if anything ever came from your planning here Bobby. I am throwing around a few ideas for my system and was thinking of integrating 4 5500W elements in the manner where you described so that only 2 could ever be on at the same time. Probably way overkill like you stated but it seems like that what we are good at on this forum.
Has anyone seen any other threads on this or anyone that has actually done this yet? Like I said I am in the early planning stages but would like to start working towards this soon. Thanks for any info
Pat
Here is a diagram that is partway there. It would require some selector switch modifications to achieve what you are looking for (being able to select any combination of 2 elements). The diagram is for 4 - 5500W elements using a 60A feed. With 4500W elements a 50A feed would be A-Ok.I wanted to bump this thread and see if anything ever came from your planning here Bobby. I am throwing around a few ideas for my system and was thinking of integrating 4 5500W elements in the manner where you described so that only 2 could ever be on at the same time. Probably way overkill like you stated but it seems like that what we are good at on this forum.
Has anyone seen any other threads on this or anyone that has actually done this yet? Like I said I am in the early planning stages but would like to start working towards this soon. Thanks for any info
Pat
Please let me know what you think.
As always - click on the image to see a full scale diagram printable on Tabloid paper (11" x 17")
Here is a diagram that is partway there. It would require some selector switch modifications to achieve what you are looking for (being able to select any combination of 2 elements). The diagram is for 4 - 5500W elements using a 60A feed. With 4500W elements a 50A feed would be A-Ok.
Please let me know what you think.
As always - click on the image to see a full scale diagram printable on Tabloid paper (11" x 17")
Thanks P-J!! I will take a look at this this afternoon and Im sure I will get back with you on it. Im in the prelim stages and just started a thread about this kind of setup. Thanks for your quick response. Look forward to chatting with you more about this.
Pat
Pat,
I did a drawing for a mod to the posted diagram that would allow you to control the elements as you want to. Both ON in the HLT or the BOIL. Or 1 ON - one each in the HLT and BOIL. Selector switch X accomplishes that for the mission.
I hope this makes sense.
I think the selector switch can be simplified a bit. The HLT enable and BK enable push buttons are controlling the pairs of contactors associated with each vessel type. If you want to be sure the HLT is OFF OFF, you disable the contactors for those vessels.
The requirement of "any two elements" could be modified as follows. Element/SSR 1 is in the HLT and always being driven off PID1. Element/SSR 4 is in the BK and is always being driven off PID2. Elements/SSR #2 and 3 are in the HLT and BK respectively but are mutually enabled via a double pole double throw selector labeled "power boost" with positions HLT and BK. On the HLT side, PID1 control is connected to SSR 2. On the BK selection side, PID 2 control is connected to SSR 3 (mutually exclusively). You could also use a center off position if you didn't want either vessel to have the extra 5500w at any given time.
To summarize this thought a bit, the selector doesn't have to influence the contactors. I suppose there is a chance for one SSR to fail closed while both HLT and BK contactors are enabled which would fire 3 elements at the same time, but the breaker will deal with that failure.
Is there anything wrong with that?
The requirement of "any two elements" could be modified as follows. Element/SSR 1 is in the HLT and always being driven off PID1. Element/SSR 4 is in the BK and is always being driven off PID2. Elements/SSR #2 and 3 are in the HLT and BK respectively but are mutually enabled via a double pole double throw selector labeled "power boost" with positions HLT and BK. On the HLT side, PID1 control is connected to SSR 2. On the BK selection side, PID 2 control is connected to SSR 3 (mutually exclusively). You could also use a center off position if you didn't want either vessel to have the extra 5500w at any given time.
To summarize this thought a bit, the selector doesn't have to influence the contactors. I suppose there is a chance for one SSR to fail closed while both HLT and BK contactors are enabled which would fire 3 elements at the same time, but the breaker will deal with that failure.
Is there anything wrong with that?
Thanks P-J,
So is this basically two of the selector switches in line. So the first switch chooses HLT, Off or BK. Then Second switch would be Element combinations?. So if I had switch 1 on Boil and Switch 2 turned to the right I would be using Elements 1,4 and to the left would be elements 4,3. And if I had first to HLT then left would be 1,2 and right would be 2,3?Just making sure Im picking up what you are putting down.
Thanks again for your expertise. You are the man!!
So is this basically two of the selector switches in line. So the first switch chooses HLT, Off or BK. Then Second switch would be Element combinations?. So if I had switch 1 on Boil and Switch 2 turned to the right I would be using Elements 1,4 and to the left would be elements 4,3. And if I had first to HLT then left would be 1,2 and right would be 2,3?Just making sure Im picking up what you are putting down.
Thanks again for your expertise. You are the man!!
Thanks for weighing in Bobby!! I couldnt believe when I was looking around and saw you had talked about this type of setup in the past. You validated a little bit of my craziness I think. Now hopefully I can make this thing happen.
I like your wording of "power boost". looking forward to seeing what comes from this discussion. Thanks again!!
Pat
Nevermind.. I'm completely off here. For some reason I was thinking any THREE elements. You'd still want a max of 2 but it would be either 1+2, 3+4 or 2+3. The reason I didn't pursue the design yet is because I may be going with a Speidel Brewmeister clone instead.
There should be several ways to implement the choice of those three states. I think it's mostly driven by how you think of the process. Do you want to be able to only have ONE element on at any given time. For example, during the boil is there any reason not to be PWM'ing 11kW? I think so because you will probably get some pulsing when it's 11kW on or off.
That would modify the states to 1+2, 2+3, 3+4 or just 4.
How about two 3-pos selector switches affecting the contactors, one for HLT and one for BK. The three positions would be labeled On (or ONE), OFF, Both.
HLT on turns on just one HLT element. Off obvious, Both turns on both.
BK "on" turns on just one BK element. Off obvious, Both turns on both.
How to prevent more than two to energize at a time (in theory):
The input to the HLT selector would route through an NC contact block under the "both" position of the BK selector. So, when the HLT is set to both, it deactivates power to the BK selector altogether. The opposite happens for the BK selector.
You could set both to off (center position). You could select ON or "ONE" on the HLT, HLT and BK, or just BK. Once you set either one of those selectors to BOTH, only that device fires both. I'm pretty sure this could be done with enough contact blocks, I just haven't figured out exactly how many. They're cheap enough.
There should be several ways to implement the choice of those three states. I think it's mostly driven by how you think of the process. Do you want to be able to only have ONE element on at any given time. For example, during the boil is there any reason not to be PWM'ing 11kW? I think so because you will probably get some pulsing when it's 11kW on or off.
That would modify the states to 1+2, 2+3, 3+4 or just 4.
How about two 3-pos selector switches affecting the contactors, one for HLT and one for BK. The three positions would be labeled On (or ONE), OFF, Both.
HLT on turns on just one HLT element. Off obvious, Both turns on both.
BK "on" turns on just one BK element. Off obvious, Both turns on both.
How to prevent more than two to energize at a time (in theory):
The input to the HLT selector would route through an NC contact block under the "both" position of the BK selector. So, when the HLT is set to both, it deactivates power to the BK selector altogether. The opposite happens for the BK selector.
You could set both to off (center position). You could select ON or "ONE" on the HLT, HLT and BK, or just BK. Once you set either one of those selectors to BOTH, only that device fires both. I'm pretty sure this could be done with enough contact blocks, I just haven't figured out exactly how many. They're cheap enough.
Sparky
Well-Known Member
Just to continue the thread and offer another method (on the below pic's), just add another (2) relays and outputs and you can have your (4) 5500W heaters.
If interested, I can give you more details since mine is for back-back batches.
If interested, I can give you more details since mine is for back-back batches.
DrivewayBeer
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I am working on a build that has very similar goals to this set up so I just subscribed to it and hope to contribute to it more soon.
I have two rigs in the works, one will be a 3 keggle set up, and the other will be a three 55 gallon drums set up.
I want to be able to control both rigs with the same control box, but never at the same time.
my keggle setup will have 1 5500W element in both the HLT and the Boil Kettle
my 55 gallon drum set up will have 2 5500W elements in both the HLT and the Boil Kettle
my Keggle set up is currently functioning great off of propane.
I already have the 55 gallon drums, 6 5500W elements, PIDs, control box, lights, and a 60A spa panal
I am still trying to figure out where to source a bunch of the other equipment such as the heat sinks and relays. I also I wanna get a TIG welder
glad to see there are others attempting this too
and Sparky that looks Great
I have two rigs in the works, one will be a 3 keggle set up, and the other will be a three 55 gallon drums set up.
I want to be able to control both rigs with the same control box, but never at the same time.
my keggle setup will have 1 5500W element in both the HLT and the Boil Kettle
my 55 gallon drum set up will have 2 5500W elements in both the HLT and the Boil Kettle
my Keggle set up is currently functioning great off of propane.
I already have the 55 gallon drums, 6 5500W elements, PIDs, control box, lights, and a 60A spa panal
I am still trying to figure out where to source a bunch of the other equipment such as the heat sinks and relays. I also I wanna get a TIG welder
glad to see there are others attempting this too
and Sparky that looks Great
kal
Well-Known Member
Old thread but I thought I'd chime in.
When I put the outlets and lights in my previous brewing room I went through all the proper electrical permitting to do this work. It included a 30A/240V dryer outlet.
All the inspector cared about was that the wiring and the things *attached to the house* were done to code.
The control panel (which he was indeed very curious about on a personal level) did not and does not factor in.
How you, the homeowner, want to use that outlet is up to you. You could plug something in that draws more current than the breaker/wiring/outlet are meant to provide. The inspector just wants to make sure that the breaker is properly sized so as to pop correctly without the wire frying if you were to do this.
That (IMHO) is the crux of it. Someone can use go past the 80% rule if they want, they should just be aware of it before building their setup. They should be aware and told that they've likely entered in a grey area as far as NEC is concerned if they ask. I think it's dangerous to recommend to people that it's fine to do without giving them the "but be aware that ..." speech. I get asked the question "can I use two 5500W elements on a 50A circuit" a lot and I simply mention that in some places (and depending on how you interpret the code), you shouldn't use more than 80% of rated capacity. I tell them to talk to their electrician and explain what they're doing to be sure. Give them the tools to make their own decision.
Kal
You don't have to since it's not hard wired (usually).
When I put the outlets and lights in my previous brewing room I went through all the proper electrical permitting to do this work. It included a 30A/240V dryer outlet.
All the inspector cared about was that the wiring and the things *attached to the house* were done to code.
The control panel (which he was indeed very curious about on a personal level) did not and does not factor in.
How you, the homeowner, want to use that outlet is up to you. You could plug something in that draws more current than the breaker/wiring/outlet are meant to provide. The inspector just wants to make sure that the breaker is properly sized so as to pop correctly without the wire frying if you were to do this.
That (IMHO) is the crux of it. Someone can use go past the 80% rule if they want, they should just be aware of it before building their setup. They should be aware and told that they've likely entered in a grey area as far as NEC is concerned if they ask. I think it's dangerous to recommend to people that it's fine to do without giving them the "but be aware that ..." speech. I get asked the question "can I use two 5500W elements on a 50A circuit" a lot and I simply mention that in some places (and depending on how you interpret the code), you shouldn't use more than 80% of rated capacity. I tell them to talk to their electrician and explain what they're doing to be sure. Give them the tools to make their own decision.
Kal
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