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04-04-2011, 08:58 PM
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#1
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Join Date: Jul 2010
Location: Warrenton, Virginia
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Two Elements - 30A?
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I have a 30A dryer outlet available and want to run a RIMS element and a Kettle element - both 5500W. The RIMS element will be wired 120V (~1375W?) and I would like to wire the kettle element to be selectable for 120v or 240v. I will run 240V during boil only (the RIMS element will be off) and what I want to know is can I run both the RIMS element and the kettle element (at 120V) at the same time? While recirculating the mash, I would like to heat up the sparge water in the kettle with 120v. I will also be running two pumps at this time. I think this is getting too close to 30 amps. (~11.5A each element + 2A/pump + 1A controls).
I know this would not be a problem with a HERMs setup, but I am using a rubbermaid cooler for the HLT and am not planning on upgrading to SS any time soon.
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04-04-2011, 09:11 PM
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#2
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If the above would work, this is what I think it should look like: (intentionally left out the SSRs and PID, etc. for simplicity)
What I would like however, is a way to not allow the second element to energize if the selector switch for the first element is on 240V. Any thoughts on this?
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04-04-2011, 10:14 PM
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#3
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Location: Miami, Florida
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Theoretically, you can. I wouldn't do it (it's too close to the limit, for comfort), but, if you have to, I'd recommend you run heater "1" off of line 2, instead of line 1. That way you're basically running both heaters in series, at 240V (each heater will run on 120V), and you'd be cutting the total heater consumption to 11.5A. And, should one of the heaters short circuit, you still have the neutral as protection.
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04-04-2011, 10:17 PM
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#4
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Location: Miami, Florida
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Sorry, I didn't see the second question.
You can do that by wiring a free set of contacts in the contactor (the middle one in your drawing) to enable the bottom contactor only when it's on.
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04-04-2011, 10:33 PM
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#5
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Join Date: May 2009
Location: Campbell, CA
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5500W is massive overkill for a RIMS element, isn't it? From what I've read on here, most have 1500W RIMS elements.
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04-04-2011, 10:46 PM
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#6
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Location: raleigh
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You should definitely fuse both of the heaters between the heater and the contactor.
I don't know if you left this off for simplicity, but I would also supply the common hot line (L1 per your drawing, or L2 per Inodoro_Pereyra's suggestion) to the top heater through a terminal block with a jumper bar and appropriately sized fuses between the contactors and the terminal block.
Remember, the breaker in the main panel is your last line of defense, and should be supplemented with proper protection for each load.
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04-04-2011, 11:05 PM
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#7
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I absolutely agree on the fuses. Didn't say it before, because I assumed you didn't draw them for simplicity purposes, but, if you weren't planning to use them, I strongly suggest you do.
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A pessimist is a well informed optimist.
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04-04-2011, 11:38 PM
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#8
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Quote:
Originally Posted by bruin_ale
5500W is massive overkill for a RIMS element, isn't it? From what I've read on here, most have 1500W RIMS elements.
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I was planning on running the 5500W element at 120V which should effectively be 1375W, unless I am mistaken. The reason for running this element is that I thought that would give me the least watt density.
Thanks all for the advice. I will be sure to use supplementary line protection, either fuses or additional breakers.
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04-05-2011, 06:09 PM
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#9
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Join Date: Feb 2011
Location: Miami, Florida
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Quote:
Originally Posted by aludwig
I was planning on running the 5500W element at 120V which should effectively be 1375W, unless I am mistaken. The reason for running this element is that I thought that would give me the least watt density.
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Yep, you're right on both.
But maybe Bruin_ale was referring to the element you'd be running on 240V?? 
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A pessimist is a well informed optimist.
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04-05-2011, 06:11 PM
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#10
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Location: Campbell, CA
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I was confused, I didn't realize he intended to use one of them at half voltage. Didn't really read the post and saw 5500W RIMs element and thought WHOA, scorch-orama.
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