Two Elements - 30A?

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aludwig

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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.
 
If the above would work, this is what I think it should look like: (intentionally left out the SSRs and PID, etc. for simplicity)

element_selector.JPG


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?
 
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.
 
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.
 
5500W is massive overkill for a RIMS element, isn't it? From what I've read on here, most have 1500W RIMS elements.
 
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.
 
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.
 
5500W is massive overkill for a RIMS element, isn't it? From what I've read on here, most have 1500W RIMS elements.

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.
 
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.

Yep, you're right on both.
But maybe Bruin_ale was referring to the element you'd be running on 240V??:confused:
 
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.
 
sorry, i have to mention this...
does your dryer outlet have 3 or 4 terminals? If its only 3 terminals, then the one that is not hot is ground, NOT neutral. if yours has 4, then you're gravy.

If its a 3 wire outlet, the you REALLY should not try to use one side for 120V. find a normal 120V outlet nearby and use that. it should draw about 11.5 A, which should be OK on most hosehold circuits. (15A seems to be pretty common im my experience). you can still use the dryer outlet for the 240V element without an issue though.
 
sorry, i have to mention this...
does your dryer outlet have 3 or 4 terminals? If its only 3 terminals, then the one that is not hot is ground, NOT neutral.

The NEMA 10 style of plug and receptacle (common on dryers) is defined as a 240V non-grounding system. That third wire is neutral, and the appliance is effectively grounded through that neutral. That wire will carry current during normal operation if the dryer has 120V items on it (like lamps or buzzers or whatever).

NEMA 10 is kind of a weird one that has exceptions for dryers and stuff in the NEC. The NEMA 14 style (hot/hot/neutral/ground) will probably eventually replace the NEMA 10, but there is still a lot of NEMA 10 out there and it's considered OK.
 
Walker,
Sorry if my post was wrong, that was just was i was told, and made enough sense to me.

Would it be appropriate to mention that you should at least check the 3rd wire for its gauge? I would be afraid that if it was a 3-wire cable pulled for the dryer, that the 3rd wire might be a smaller gauge (which i have seen in a few runs, since it was intended for grounding only) and may not be safe for the current draw needed for the element.

Again, sorry for the 'chicken-little' post previously if it was inaccurate.
 
Walker,
Sorry if my post was wrong, that was just was i was told, and made enough sense to me.
No worries. I had it wrong for a long time, too, and assumed that the third wire was ground. I don't even know what prompted me to look more closely at it a few weeks ago, but that's when I learned that it was neutral and not ground.

Would it be appropriate to mention that you should at least check the 3rd wire for its gauge? I would be afraid that if it was a 3-wire cable pulled for the dryer, that the 3rd wire might be a smaller gauge (which i have seen in a few runs, since it was intended for grounding only) and may not be safe for the current draw needed for the element.

Again, sorry for the 'chicken-little' post previously if it was inaccurate.

Yes, it's probably a good idea to check the wire, but the third wire is not mant as ground only. It carries current for the 120V items and should be a properly shielded wire. It *might* be smaller gauge, but it seems like it would be more of a PITA for a contractor to run 2 heavy wires and then separately run one thin wire for the neutral.

but you never know....
 
that all makes sense. The only reason I mentioned the gauge was because I've seen jacked 3 wire where the 3rd un-insulated ground wire was definitely a smaller gauge (found it at home depot, so it can't be terribly uncommon).

but just as every knows in this forum, when it comes to electricity, better safe than sorry. thats the only reason I mentioned it.
 
that all makes sense. The only reason I mentioned the gauge was because I've seen jacked 3 wire where the 3rd un-insulated ground wire was definitely a smaller gauge (found it at home depot, so it can't be terribly uncommon).

but just as every knows in this forum, when it comes to electricity, better safe than sorry. thats the only reason I mentioned it.

Yeah.... it's common to use a smaller (and often unshielded bare copper) wire for a connection to a receptacle that is a ground connection. Ground wires should never carry current under normal circumstances.
 
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