Control box for 120 AND 240...is it possible?

I have a control box I'm building up now that is running on 120V, but I have built with the capability/plan to convert to 240V when I have the proper power feed. The control box only runs the HLT heater and the temp monitoring probes right now...wont control the boil keggle until I have 240 since I am doing 10 gal batches. At that point, I will run both the second porwer feed through the contactor and add the second SSR. I'm curious though if it would be possible to wire a control box up to be able to run 120 AND 240 elements. I'm now thinking of making a small 2.5 gal setup for test batches that I can run on a 120V outlet(so I can brew in the kitchen since I dont have a pretty basement brewery), but would like to use the same control panel if possible. I know the PID's would run on 120 in either scenario since it only getting one hot leg and a neutral. I'm no electrical engineer, but would this be as easy as having 2 different power inputs, the 120 wired directly to the hot bus in side then through the SSR, the 240 split, one leg to the hot buss one leg straight through the contactor to the element output(4 pole connector). That way the 240 should work as designed, and the 120V kettle/HLT will only use the grount, neutral and the one SSR switched hot lead from the output plug.

Again, this all seems kosher in my head, but I have no idea if this would work in reality.

I should mention that all of the indicator lamps, switches and pumps are running off 120V, and the plan is to keep it that way. the only 240V power drain is the element.

You want to be able to run with either 120 or 240 with the same control box, not both 120 and 240 at the same time?

Correct, one or the other. It will do most of its duty on the 240v-15 gallon rig, but i would like to power a smaller 120v-2.5 gallon (likely BIAB with a single element) countertop kettle as well without building another panel. If i get a chance tomorrow, I'll post aome rudementary schematics and hopefully someone will point out if they are bogus or wont work.

It could be done. The elements run on three wires. Hot A, Hot B, and ground when 240v and Hot, Neutral, and Ground when 120. You would then have two plugs - one that jumpered Hot B and Neutral so that you ran at 120 and another that had them separate for when you ran 240.

You would want to make extra sure you have a good wiring diagram that you mentally troubleshoot repeatedly before actually wiring it up, but it seems doable.

Interesting thought problem.... I would think it would be easier, with fewer components, if you derive 120V from your 240V feed, when you run it. If you want to use the same PID and SSR whether in 120V or 240V mode, you would then always have H1 of your 240V feed running through the SSR. I don't know whether you can safely use H1 from a 240V feed and neutral from a separate 120V feed, but it makes me a bit nervous.

If you did this, and had the 240V feed, for each PID/SSR controlling a 120V or 240V element, you could use a 3-position selector switch, 120V-Off-240V. You would have two contactors, one for the 120V circuit (contactor1) and the other for the 240V circuit (contactor2). H1 runs through the SSR, then you split it and run it to both contactors. H2 runs to the contactor2 for the 240V circuit. After contactor1 H1 goes to a 120V receptacle, and neutral is tied in there also. After the contactor2, H1 and H2 run to a 240V receptacle. Of course, grounds are run to both receptacles. So now, selecting 120V closes contactor1 and opens contactor2, selecting 240V opens contactor1 and closes contacto2r, and selecting Off opens them both. I would also consider wiring a 120V led light in parallel with the 120V receptacle, and a 240V led light in parallel with the 240V receptacle, so you can get a visual confirmation when an element really has power.

Before you run your 240V circuit, you would have a 120V power inlet into your control panel, your 120V Hot input would go through an additional main power contactor, to your hot bus, then as described. You could defer (but leave room for) contactor2 for 240V, 240V receptacle, 240V led light, and the splitting of the Hot.

When you do install the 240V, you would swap out the 120V inlet for a 4-wire 240V inlet, then run Hot1 and Hot2 through your main power contactor, run Hot1 to your hot bus, and install the additional 240V componenents (contactor, receptcacle, led light, splitting of the Hot).

I think this would work, but I am not an electrician. Good luck with it.

I was thinking about something similar. I think if you have your entire rig set up to work with 120 except use 10 gauge wire for the elements and any thing else that needs 240v. You would then only need 1 additional relay. When it is not energized the 120 neutral would be passed through to the elements. Have the coil energized by H2 and when energized, this would then open the 120 neutral and pass the H2 to the elements.

Yes, you can do that--that's exactly the way my rig is set up. I can run both 120VAC heatsticks and the 240VAC elements in my HLT and BK. Make sure that when you pull in the wires for 240VAC that you have 4 wires. US household power systems have two hot legs that are 180 degrees apart, a neutral leg, and a ground leg. For 120VAC, you can pull from either hot leg to neutral and for 240VAC you pull from each hot leg. Think of two sine waves--the voltage from the peak of one sine wave to the zero line is 120VAC while the voltage from the peak of one wave to the trough of the other is 240VAC. Your SSRs can still cut just one hot leg, but the other leg will be a neutral for 120VAC or the other hot for 240VAC. I would recommend separate plugs for each voltage though--less chance of screw ups and the plug connectors are separately rated for voltage and amps.

In the pictures you can see the two 120VAC recepacles for heat sticks (each from a different hot leg) and one 240VAC receptacle for the HLT element along with the schematic showing how they're wired up.

I was under the impression that OP wanted to run the same panel on a 120v feed OR a 240v feed depending on the size of the batch / where he was / what power was available. If the comment was to run one panel with a 120v feed AND a 240v feed at the SAME time, then ignore everything I said in my previous comment. Running both at the same time creates some issues with the GFCI side of things from what I understand.

BadNews, you were right...I want to run EITHER 120 or 240 depending on where I am/which setup I use. I've included a verychildish looking wiring diagram (I'm at work and dont have access to anything to make it look nice). The design hinges on a 3 way switch with 2 NO contacts to activate the power input contactor for wither the 120 or the 240 feed depending on which is used. On the element out side there would be one unused contact in the plug, but this isnt and issue...there just wont be a wire in the element cable attached to it. I think this is close to exactly what jeffmeh was trying to explain, but I'm a visual person and needed to see it on paper...

View attachment 240_120_wiring_diag.pdf

So there are a few more questions.
Do you plan to run your pumps off this setup? Do you plan to run anything that HAS to be 120v (like the pumps, or some LED switches, or a contactor, or...)

If the answer to the above is yes, then you want to do something like what I've shown in the attachment. Under 240v mode, you have 4 wires: Hot A (red), Hot B (Black), Neutral (Blue), and Ground (Green). Everything is powered like normal. I show the PID being powered by 240v, but you could just as easily power it with the red and a blue line to run it at 120v. Your element is getting 240v, and you essentially have a panel similar to most on this board with 240v and 120v running around inside.

Under 120v mode, you disconnect the 240v plug and put in your 120v plug (3 wires instead of 4), and you flip the switch (close the contact). Now you have essentially jumpered the Hot B and Neutral lines, so anything that used to run off Hot B now only gets neutral. The PID now is running off 120v, the element is running off 120v, etc. It should work fine, as long as you don't flip that switch without switching out the plug first! If you go this route, I'd highly suggest some sort of covered aircraft style 'missile launch' switch, where you have to raise the cover before pushing to make certian you don't acidentally jumper Hot B and Neutral while under 240v.

Now - back to my first question - if you discover that everything in your panel can run at 120 OR 240 (like the PID and element can) then you save yourself some hassel. Wire up TWO plugs, both with three wires. Your 240v plug will have Hot A, Hot B, and Ground - you can eliminate the neutral. Your 120v plug will have Hot A, Neutral, and Ground. Make sure that the neutral line on the 120v plug lines up with where the Hot B was going for the 240v plug. Now you're essentially using the plugs as the switch, but accomplishing the same thing.

I hope this helps point you in the right direction. It's an interesting concept and a unique idea. You could definitely do it if you get the right parts and wire the panel up correctly, but you're also opening yourself up for some potential hurt if you do something wrong and short Hot B to Neutral in your panel...

-Kevin

View attachment 120&240v control panel.pdf

I was suggestnig something similar to this but instead of the manual switch from 120 to 240, I was suggesting another relay that would be powered by the additional hot leg. If there is not the second hot leg, the relay would not energize and the neutral would be passed along to the elements. If it is energized, then the second hot leg would be passed to the elements. Just removes the need for the user to manually flip a switch and would be controlled automatically based on the power supply,

Good stuff. You also might want to consider only using 240V elements (they will run at 1/4 the wattage at 120V), so that you cannot inadvertently run a 120V element at 240V.

h_c,
Sorry, I understand what you were asking now. I've marked up your diagram a bit to reflect how it could be done, showing the neutral and ground bus connections. You would need to ensure that the 240VAC power source had a neutral wire also. You would need to size all wiring, connectors, and receptacles for 240VAC and whatever amps your largest element will draw (say 30A rating for 5500W/240VAC element), regardless if you're connecting 120VAC or 240VAC. Your approach would work if you used connectors that have 4 pins, like NEMA L14-30P (this is the kind you would need for your incoming 240VAC power). One pin would always be unused for 120 or 240VAC power, though. They're a bit more expensive than the typical NEMA L6-30P receptacles and plugs with 3 contacts that many use for elements. In that case, one contact would be a hot and one would be the ground regardless of voltage and you would need some way to switch the 3rd contact between neutral for 120VAC or the other hot for 240VAC. That could be another contactor driven from your switch. Probably be easier to use the 4-pin connectors, though.

View attachment 240_120_wiring_diag3.pdf

View attachment 240_120_wiring_diag2.pdf

msexton said:

I was suggestnig something similar to this but instead of the manual switch from 120 to 240, I was suggesting another relay that would be powered by the additional hot leg. If there is not the second hot leg, the relay would not energize and the neutral would be passed along to the elements. If it is energized, then the second hot leg would be passed to the elements. Just removes the need for the user to manually flip a switch and would be controlled automatically based on the power supply,

Click to expand...

So presumably, the relay in it's open state would short Hot B to Neutral and allow everyting to run at 120. Throw 240v into the system and the coil closes and the switch opens and runs Hot B to Hot B, right? The problem - it takes a few miliseconds for the coil to power up and the switch to open. During that time, you have a Hot to Neutral short. I'm not positive, but I'd wager that you'd trip the breaker or GFCI 10 times out of 10 going this route.

at3brew9 said:

h_c,
You would need to ensure that the 240VAC power source had a neutral wire also.

Click to expand...

Not really... if all his equipment coul run off 120-240v, like the PIDs and LEDs from Auber, he would only need 3 wires. Hot A / Hot B / Ground in 240 mode, Hot A / Neutral / Ground in 120 mode. The 4th wire for the neutral is only useful if you're trying to derive 120v from a 240v source, and if his equipment can all run at 240v, there's no point in running the extra wire.

-Kevin

BadNewsBrewery said:

So there are a few more questions.
Do you plan to run your pumps off this setup? Do you plan to run anything that HAS to be 120v (like the pumps, or some LED switches, or a contactor, or...)

If the answer to the above is yes, then you want to do something like what I've shown in the attachment. Under 240v mode, you have 4 wires: Hot A (red), Hot B (Black), Neutral (Blue), and Ground (Green). Everything is powered like normal. I show the PID being powered by 240v, but you could just as easily power it with the red and a blue line to run it at 120v. Your element is getting 240v, and you essentially have a panel similar to most on this board with 240v and 120v running around inside.

Under 120v mode, you disconnect the 240v plug and put in your 120v plug (3 wires instead of 4), and you flip the switch (close the contact). Now you have essentially jumpered the Hot B and Neutral lines, so anything that used to run off Hot B now only gets neutral. The PID now is running off 120v, the element is running off 120v, etc. It should work fine, as long as you don't flip that switch without switching out the plug first! If you go this route, I'd highly suggest some sort of covered aircraft style 'missile launch' switch, where you have to raise the cover before pushing to make certian you don't acidentally jumper Hot B and Neutral while under 240v.

Now - back to my first question - if you discover that everything in your panel can run at 120 OR 240 (like the PID and element can) then you save yourself some hassel. Wire up TWO plugs, both with three wires. Your 240v plug will have Hot A, Hot B, and Ground - you can eliminate the neutral. Your 120v plug will have Hot A, Neutral, and Ground. Make sure that the neutral line on the 120v plug lines up with where the Hot B was going for the 240v plug. Now you're essentially using the plugs as the switch, but accomplishing the same thing.

I hope this helps point you in the right direction. It's an interesting concept and a unique idea. You could definitely do it if you get the right parts and wire the panel up correctly, but you're also opening yourself up for some potential hurt if you do something wrong and short Hot B to Neutral in your panel...

-Kevin

Click to expand...

Is it really as simple as switching 240V Hot B and 120V Neutral? I believe that in 120V mode that is mixing 240V Hot A with 120V Neutral. Would it trip the 120V GFCI if 120V hot has no current but 120V neutral does? Even if not, is that good practice?

I think you're still thinking about this the wrong way. He will not be running 120 and 240 at the same time. He will run 120 or 240. The neutral will be derived from the same circuit the power is coming from. So, as long as his 240 supply is GFCI protected and his 120 source is protected he should be fine.

BadNews, I see what you are saying and I didn't think it would be possible to short the neutral and H2 but I am going off memory. I will need to check my relay when I get home. I thought that there were 2 separtate paths for the Normally open and normally closed that could be used that would not short them. I will check.

BadNewsBrewery said:

I think you're still thinking about this the wrong way. He will not be running 120 and 240 at the same time. He will run 120 or 240. The neutral will be derived from the same circuit the power is coming from. So, as long as his 240 supply is GFCI protected and his 120 source is protected he should be fine.

Click to expand...

Ah, one power inlet in the control panel, with two different power cords. One plugs into a 120V outlet and has H-N-G, the other plugs into a 240V outlet and has, say, H-H-N-G. When the first is plugged in there is no second hot, and the neutral must go to the element. When the second is plugged in, the second hot (not the neutral) must go to the element.

Assuming I get it, very elegant.

jeffmeh said:

Ah, one power inlet in the control panel, with two different power cords. One plugs into a 120V outlet and has H-N-G, the other plugs into a 240V outlet and has, say, H-H-N-G. When the first is plugged in there is no second hot, and the neutral must go to the element. When the second is plugged in, the second hot (not the neutral) must go to the element.

Assuming I get it, very elegant.

Click to expand...

Bingo. So basically the Hot B wire in the panel is doing double duty...

msexton said:

BadNews, I see what you are saying and I didn't think it would be possible to short the neutral and H2 but I am going off memory. I will need to check my relay when I get home. I thought that there were 2 separtate paths for the Normally open and normally closed that could be used that would not short them. I will check.

Click to expand...

I see now, it sounds like a SPDT relay(I think thats right anyway) where its not just off/on, but rather has the two separate circuits that it toggles between and closes one or the other, right?

Brainstorming here:

I would consider a 3-position selector switch (120V - Off - 240V), controlling a DPST contactor with both hot legs, so Off would power down the whole panel, except for the switch.

After that contactor, I would put a SPST contactor between H2 and the element. I would also put a SPST contactor between neutral and the element. So with the selector switch above, selecting 120V would also open the circuit between H2 and the element and close the circuit between neutral and the element. This would prevent H2 shorting to neutral if using the 240V cord but inadvertently selecting 120V. Selecting 240V would close the circuit between H2 and the element, and open the circuit between neutral and the element.

Under this scenario, using the 120V cord and selecting 240V would not power the element, so no danger there.

I would also go with a 2-position switch that could shut off power to the element, using another DPST contactor with both hots running through it between the SSR and the element.

I think one could also wire a 120V/240V LED in parallel to the element, to indicate whether the element is on, running both H2 and Neutral to the LED.

Interesting stuff.

Edit: I think a SPDT contactor would work in lieu of the 2 SPST ones.

I think mine are DPDT relays and it doesn't look like there would be any way that the neutral and H2 could get shorted. The elements would either receive neutral if there was no H2 supplied or the second hot leg if connected to 220.

Here's my concern - anything using the 240v Hot B line to switch a relay has the chance of shorting, unless I'm totally missing something. The concept I've been running with in my head is that, while in 120v mode, the panel has Hot B and Neutral shorted together sharing the same pathway. As soon as you go to switch over to 240v mode, and run power to Hot B, you're going to have a short because whatever switch that is supposed to electrically operate will take a fraction of a second to break the circuit, and by then the short has already happened. Unless you find a switch that operates faster than the speed of light, I don't see there being a safe way to have the panel automatically switch between 120 and 240 depending on what power you feed in.

Possible solutions though - 1: Only run the panel as 100% 240/120 compatible devices, so you only have 3 wires. Hot A, Ground, and one wire that is either 100% Hot B or 100% Neutral depending on what plug end you put in. Then you never have to worry about shorts and ground faults, and everyone wins.

2: Put in a series of switches that the operator has to remember to select prior to plugging anything in. Actual mechanical switches are the only safe way I see to do this, as using contactors or relays still require that fraction of a second for the coils to fire up and open or close a connection. If you did it the way jeffmeh suggests, with the 3 position switch, you would wire it up safely because both legs would be open before you closed one side or the other.

Going with option 2 seems excessively complicated when option 1 would work fine for the majority of control panel equipment. PIDs, LED switches... most seem to run on either 120 or 240 and are fine switching themselves. I'm not sure if you can find a contactor with a 120-240v coil.

I think the first step, if OP is still serious about this, is to figure out if you need to have a 4 wire panel (so you can run 240/120 at the same time for contactors / pumps / whatever) or if you can make everything work with devices that will run on 120 or 240 so you can run a 3 wire panel.

BadNews, I will have to use 120 to power my pumps in either voltage inpout scenario as I have chugger pumps and as far as I know they only operate on 120V. Everything else can be set up to operate on 240 with just minor changes (a few LED's and switches)...if anyone knows of a motor that will fit march pumps that can run on 120-240 AC, I'd love to check it out. As far as I know you can get the pumps from march in one configuration or the other...but I dont think any of the motors will do double duty. Maybe I'll have to check out those little 12V great-breweh pumps since I can find a transformer that'll go from 240 AC down to 12v DC relatively easily. Has anyone tried these with cood results? How do they compare to the march/chugger?
http://greatbreweh.com/Beer_Pump.html

So you may need 4 wires to derive 120v for the pump in a 240v scenario. The only other options are to go with the 12v pump as you mention (no experience there), find some sort of dedicated transformer that will drop 240v to 120 while also being able to push 120 straight through if that's what's provided, or plugging the pump into a different outlet.

You can definitely do the 4 wire method, just make sure you go the route that makes sure the Hot B to Neutral short is COMPLETELY broken before it turns in to 240v.

BadNewsBrewery said:

Here's my concern - anything using the 240v Hot B line to switch a relay has the chance of shorting, unless I'm totally missing something. The concept I've been running with in my head is that, while in 120v mode, the panel has Hot B and Neutral shorted together sharing the same pathway. As soon as you go to switch over to 240v mode, and run power to Hot B, you're going to have a short because whatever switch that is supposed to electrically operate will take a fraction of a second to break the circuit, and by then the short has already happened. Unless you find a switch that operates faster than the speed of light, I don't see there being a safe way to have the panel automatically switch between 120 and 240 depending on what power you feed in.

Possible solutions though - 1: Only run the panel as 100% 240/120 compatible devices, so you only have 3 wires. Hot A, Ground, and one wire that is either 100% Hot B or 100% Neutral depending on what plug end you put in. Then you never have to worry about shorts and ground faults, and everyone wins.

2: Put in a series of switches that the operator has to remember to select prior to plugging anything in. Actual mechanical switches are the only safe way I see to do this, as using contactors or relays still require that fraction of a second for the coils to fire up and open or close a connection. If you did it the way jeffmeh suggests, with the 3 position switch, you would wire it up safely because both legs would be open before you closed one side or the other.

Going with option 2 seems excessively complicated when option 1 would work fine for the majority of control panel equipment. PIDs, LED switches... most seem to run on either 120 or 240 and are fine switching themselves. I'm not sure if you can find a contactor with a 120-240v coil.

I think the first step, if OP is still serious about this, is to figure out if you need to have a 4 wire panel (so you can run 240/120 at the same time for contactors / pumps / whatever) or if you can make everything work with devices that will run on 120 or 240 so you can run a 3 wire panel.

Click to expand...

Hey, my view is that the OP's requirement to run the same panel at either 120 or 240 is what is excessively complicated, not my suggested solution that would make it safe even when selecting the wrong voltage for the input supplied (selecting 120v with the 240v input would still have the element at 120v, selecting 240v with the 120v input would not power the element). I am deeply offended, lol.

If you use a 4 wire connector for input power and a 4 wire connector for each heating element, you should be able to design a 240v panel with no additional relays, switches, etc. The 240v elements will use the H-H-G wires and the 120v elements will use the H-N-G wires.

You either connect the 240v input power and 240v elements.
OR
120v input power and 120v elements depending on the application.

jeffmeh said:

Hey, my view is that the OP's requirement to run the same panel at either 120 or 240 is what is excessively complicated, not my suggested solution that would make it safe even when selecting the wrong voltage for the input supplied (selecting 120v with the 240v input would still have the element at 120v, selecting 240v with the 120v input would not power the element). I am deeply offended, lol.

Click to expand...

Hahahaha. No doubt. Looking over what you wrote, your solution is pretty solid. You'd just need to wire it up like I've shown - the Hot side bus downstream of the contactors, and the neutral bus upside of the contactor. So, if you were to plug in 240v but select 120v, your hot B would be broken and everything would run at 120v. If you selected 240v and only ran 120, it wouldn't half work, but the elements wouldn't work at all.

Can your offendedness and HAHB.

jCOSbrew said:

If you use a 4 wire connector for input power and a 4 wire connector for each heating element, you should be able to design a 240v panel with no additional relays, switches, etc. The 240v elements will use the H-H-G wires and the 120v elements will use the H-N-G wires.

You either connect the 240v input power and 240v elements.
OR
120v input power and 120v elements depending on the application.

Click to expand...

The intent is to not have 240 AND 120, it's to have one set of equipment that could run 240 OR 120. So having a second set of elements defeats the OP's intent.

The control panel shouldn't care what element is hooked up or what power source is connected.

jCOSbrew said:

The control panel shouldn't care what element is hooked up or what power source is connected.

Click to expand...

How do you figure? If he has an element hooked up with Hot A, Hot B, and Ground, and he plugs the panel into a 120v source (only supplying Hot A, Neutral, and Ground) his element will never heat up.

jCOSbrew said:

If you use a 4 wire connector for input power and a 4 wire connector for each heating element, you should be able to design a 240v panel with no additional relays, switches, etc. The 240v elements will use the H-H-G wires and the 120v elements will use the H-N-G wires.

You either connect the 240v input power and 240v elements.
OR
120v input power and 120v elements depending on the application.

Click to expand...

As BadNews pointed out, you would not be able to do that with a single set of elements that would run in either mode.

However, I think it is a very good and simple suggestion. In practical terms, it would be difficult to size the vessels and elements appropriately to run at 240v and also at 120v at 1/4 of the wattage. So it may make more sense to have the "full" system with vessels and 240v elements, and the "small" system with smaller vessels and 120v elements.

Two input cables (240v with H-H-N-G, 120v with H-N-G), both terminating at the control panel with something like nema 14-30. The 240v one has a nema 14-30 plug, the 120v one has a nema 5-15 or 5-20 plug.

Two element cables (240v with H-H-G, 120v with H-N-G), both terminating at the control panel with nema 14-30, with the elements wired appropriately.

My suggestion implies some constraints on the design:

* 4 wire input power connection and heating element connections.
* Connect a 120v power cord OR a 240v power cord.
* Heating element cords use the appropriate 3 wires (H-H-G for 240v or H-N-G for 120v)
* 120v input power can be used with 120v elements (like OP requested) as well as PID, pumps, etc.
* 240v input power can be used with 240v (or 120v) elements, PID, pumps, etc.

I think this achieves what the OP requested. Design a panel that can be used with 120v now and 240v later with the appropriate power source, 240v element, and cords. No need for additional components or complexity inside the panel. 240v panel designs are just controlling 1 phase of AC power (just like 120v panels).

jCOSbrew said:

Design a panel that can be used with 120v now and 240v later with the appropriate power source, 240v element, and cords.

Click to expand...

My understanding was that his goal was to have a panel that could run either. 240v today, 120v tomorrow, 240 again on Thursday - depending on where he brewed. So having different elements would complicate things.

120v and small kettle for 2.5 gal batch today.

240v and keggle for 10 gal batch tomorrow.

The 120v power source limits the capacity. If/when you upgrade to 240v power the cost of the element is $20 and it will probably go in a larger vessel. Otherwise there is no reason to upgrade the power source.

I have another concern of how you get the power into the control panel. If you have two cables hard wired into the panel, there is a danger (in my mind) that the unplugged one would be hot. This may have been covered earlier and I forgot.

Absolutely would be hot. I'd say either two separate plugs that go into the panel (single receptical) or a fitting / adapter that converts your 4 wire 240v plug into a 3 wire 120v plug

The solutions being discussed only have one inlet for a power cord, so only one power cord at a time.