Amp, gauge, duty cycle recommendations

P-J said:

Perhaps it might help you to better understand wire ratings if you did a little more research instead. Take a look at this wire chart:
Wire Chart
Please note that #8 copper wire is capable of carrying 50 or 55A depending on the wire's insulation.
Oh - and the information is from NEC.

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Thank you for posting this. It does depend on the insulation.

I just have a trivial question, though. I have 8 gauge wire with insulation (THHN) that can handle 55 amperes, according to NEC. Is it okay for me to consistently run 55 amperes through it? I don't plan on doing so - just wondering.

EarthBound said:

Thank you for posting this. It does depend on the insulation.

I just have a trivial question, though. I have 8 gauge wire with insulation (THHN) that can handle 55 amperes, according to NEC. Is it okay for me to consistently run 55 amperes through it? I don't plan on doing so - just wondering.

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You are Welcome..
Yes it is A-Ok to run it that way. No problem at all.

P-J said:

Perhaps it might help you to better understand wire ratings if you did a little more research instead. Take a look at this wire chart:
Wire Chart
Please note that #8 copper wire is capable of carrying 50 or 55A depending on the wire's insulation.
Oh - and the information is from NEC.

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Thanks for that, I stand corrected...

cwi said:

It is this kind of stuff why I review prior art if it is available. There are all kinds of PWM out there, from DC with <.1 Hz to HF AC with > 20Khz. The information that is important is that which applies to the situation at hand.

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Read it again. I said PIDs, not PWMs.

The PIDs out there that are commonly used for brewing will not allow you to specify a output period of less than 2 seconds. So when you are using a PID like that in manual mode for PWM functionality, you can go no faster than 0.5Hz. You are permitted to slow down from there, but 0.5Hz is the max.

Walker said:

Read it again. I said PIDs, not PWMs.

The PIDs out there that are commonly used for brewing will not allow you to specify a output period of less than 2 seconds. So when you are using a PID like that in manual mode for PWM functionality, you can go no faster than 0.5Hz. You are permitted to slow down from there, but 0.5Hz is the max.

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I was essentially agreeing with you, and commenting that the factual info you provided regarding PIDs and their typical cycle times is exactly the type of info the OP needs to review for his design.

I did muddle it up with the info on the varied nature of PWM stuff available out there, but only because that is what the OP is planning on using.

Edit: I tried to clean up the previous post to make that clear, but it's late so it may be worse. The main point was to get some facts before playing around with 50 amp SSRs.

There was earlier talk of PIDs and higher freqs. Cleanly switching that much power that fast with a typical high current SSR raises my warning flags enough to check before trying that. If one would even respond that fast, I would guess that driving the SSR close the the line freq would require accounting for phase harmonics/alignment issues, but I don't really care enough to find out.

For the record I never once said I would use a cycle time any faster than 1Hz. I did make the mistake of thinking PID's used a much quicker cycle but in my own words said that would be rough on the SSR. I did suggest that PWM is PWM be it at a kHz cycle or .5Hz cycle.

That being said, cwi, why don't you actually give us some useful information and tell us about your brewery. I can tell you're dying to tell us all how smart you are.

Spintab said:

For the record I never once said I would use a cycle time any faster than 1Hz. I did make the mistake of thinking PID's used a much quicker cycle but in my own words said that would be rough on the SSR. I did suggest that PWM is PWM be it at a kHz cycle or .5Hz cycle.

That being said, cwi, why don't you actually give us some useful information and tell us about your brewery. I can tell you're dying to tell us all how smart you are.

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I did give you useful information: Go find out some facts and review some proven designs, instead of designing high power electronics to chat room specs.

Here is a common sig in electric related threads:
Warning:
If you get advice on an electric brewing rig, you need to take it to a licensed electrician or two to have it looked over.
This stuff can kill you. When it comes right down to it, we're just some dudes on the internet.
I have seem some TERRIBLE advice on here in the past few months. I may even be guilty of bad advice myself.

I use gas, and am only considering electric for an HLT and HEX. A standard temp controller tied to an SSR is good enough for that, but if I want PID and proportional output, I will just buy one for ~$50.

cwi said:

I was essentially agreeing with you, and commenting that the factual info you provided regarding PIDs and their typical cycle times is exactly the type of info the OP needs to review for his design.

I did muddle it up with the info on the varied nature of PWM stuff available out there, but only because that is what the OP is planning on using.

Edit: I tried to clean up the previous post to make that clear, but it's late so it may be worse. The main point was to get some facts before playing around with 50 amp SSRs.

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Got'cha. the edited post is definitely clearer.

cwi said:

Here is a common sig in electric related threads:
Warning:
If you get advice on an electric brewing rig, you need to take it to a licensed electrician or two to have it looked over.
This stuff can kill you. When it comes right down to it, we're just some dudes on the internet.
I have seem some TERRIBLE advice on here in the past few months. I may even be guilty of bad advice myself.

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LOL. That was my sig that I removed quite some time ago. Are other people actually using it?

P-J said:

Perhaps it might help you to better understand wire ratings if you did a little more research instead. Take a look at this wire chart:
Wire Chart
Please note that #8 copper wire is capable of carrying 50 or 55A depending on the wire's insulation.
Oh - and the information is from NEC.

Click to expand...

Great table. My comments were for THHN copper. I agree that the gauge wires are capable of carrying higher amperage, however I don't know any electrical inspector that would let you put a 25A breaker on a circuit with 14/2.

-Steve

Walker said:

LOL. That was my sig that I removed quite some time ago. Are other people actually using it?

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I thought that was yours, but didn't see it in your current posts. I just searched for it with keywords, and it came up so at least one guy is currently using it. I remember when I first noticed it, and there was some scary advice being given. Guys were even removing their correct advice to divorce themselves from the situation.

spintab said:

that being said, cwi, why don't you actually give us some useful information and tell us about your brewery. I can tell you're dying to tell us all how smart you are.

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+1 lmao!

EarthBound said:

+1 lmao!

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I really don't see what is so funny about recommending someone get some facts instead of relying on internet chat rooms for electrical advice, but I guess you must:

EarthBound said:

Thank you for posting this. It does depend on the insulation.

I just have a trivial question, though. I have 8 gauge wire with insulation (THHN) that can handle 55 amperes, according to NEC. Is it okay for me to consistently run 55 amperes through it? I don't plan on doing so - just wondering.

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Why not just pick your favorite answer from one of several conflicting ones already posted.

cwi said:

I really don't see what is so funny about recommending someone get some facts instead of relying on internet chat rooms for electrical advice, but I guess you must:



Why not just pick your favorite answer from one of several conflicting ones already posted.

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cwi, I mean this in the absolute nicest way so take this advice as constructive criticism and not as a personal attack. Your attitude here doesn't appear to be winning you any friends. You seem to be smart and well informed but your posts are typically formatted in such a way as to showcase your intellect while subtly mocking others. You are the living, breathing definition of smarmy. I think you mean well and often give out very good advice but it gets overlooked or discounted because of the manner in which you deliver it.

Back to the original question of wire gauge and ampacity, there are going to be different answers because there is no hard rule about what gauge is correct. The NEC has it's rules and various other wiring books and guides have theirs. It will depend on the application. I would certainly err on the side of caution if the wiring were inside my walls and I ran the risk of burning down the house. I'm far less concerned when the length is very short, the wire is run through the air, and the wire is run singly (i.e. chasis wiring). It's all about comfort level.

I think there are a lot of risks in electric brewing but honestly, undersized wire catching fire in the event of a short is very low on my list. Others may disagree and they should plan their build accordingly. I think everyone here has suggested that each person should do their own homework and do what they are comfortable with.

Lost said:

You are the living, breathing definition of smarmy.

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It has usually been referred to as snarky, but smarmy probably fits also.

I would say the guy deserved it after going to the trouble of posting a 'lmao' in response to someone else's equally smarmy comment directed at me. I usually only get smarmy after the other side already has.

Lost said:

I think everyone here has suggested that each person should do their own homework and do what they are comfortable with.

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This did not happen, and was the reason why I posted. Somebody posted saying that it was perfectly OK to drive the SSR at whatever freq one wants, even after others said not to. I just suggested getting some factual info.

Lost said:

cwi, I mean this in the absolute nicest way so take this advice as constructive criticism and not as a personal attack. Your attitude here doesn't appear to be winning you any friends. You seem to be smart and well informed but your posts are typically formatted in such a way as to showcase your intellect while subtly mocking others. You are the living, breathing definition of smarmy. I think you mean well and often give out very good advice but it gets overlooked or discounted because of the manner in which you deliver it.

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Thank you Lost. I wasn't sure if I was being over sensitive about the attitude. It comes across as patronizing when what we really want is a piece of the smarts. I get smarmy when my ability is questioned in a patronizing manner especially when it's not backed by solid evidence of actually being wrong. I don't feel I was the first to smarm but if I was then I apologize. I've already dropped the idea of going electric any time soon anyway due to budget limits.

I don't expect direct answers coming here asking for advice. Sometimes you get them and they're from someone qualified to give them and bingo. Sometimes people clue you in on what you need to do homework on. Other times you're just looking for someone who has also assigned themselves with the same homework you've assigned yourself. Perhaps they've found links to legitimate sources of info, and maybe you've found some they haven't. In the end you've both saved each other time and Googling. I mean what if you started a thread about typical malts in an amber and the first response was to go do your homework as opposed to a link to a clone of a commercial amber? You could also get a response that it contains 80% roasted barley. At that point it's up to the OP to choose their own fate by directly using that advice or cross referencing it against another source.

Can we just go back to making beer now?

Spintab said:

I get smarmy when my ability is questioned in a patronizing manner especially when it's not backed by solid evidence of actually being wrong.

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I qualified my questioning of your knowledge level, and that it may not be the case. It was more related to your ability to screen all the conflicting info that had already been presented. I never posted any specs or system advice other than the existence of other forums, which I listed, that are more focused on this topic.

Spintab said:

I mean what if you started a thread about typical malts in an amber and the first response was to go do your homework as opposed to a link to a clone of a commercial amber? You could also get a response that it contains 80% roasted barley. At that point it's up to the OP to choose their own fate by directly using that advice or cross referencing it against another source.

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That is why my initial advice was to try the arduino and brewtroller boards which are populated with people more focused on electronics than beer. I don't see how that was equivalent to me telling you to go do your own research.

Keep in mind this was after conflicting posts regarding SSR driver freqs, PID behavior, wiring specs, etc. I was only suggesting another source of info and input that may be a better choice for cross referencing, as you say. It appeared to me that you had already received the 80% roasted barley advice. 2% and 40% as well.

Spintab said:

I don't feel I was the first to smarm but if I was then I apologize.

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Like identifying porn, classifying smarm is something only a jury of peers could determine, or maybe a governmental agency. Less fun than id'ing porn, though.

cwi said:

Like identifying porn, classifying smarm is something only a jury of peers could determine, or maybe a governmental agency. Less fun than id'ing porn, though.

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Ok, I like you again now.