Control Box Wiring: 120 & 240 Separate?

[Mojzis]

Right now I have a PWM setup for my 5500W element installed in box. I also have an amp & volt meter and cooling fan in there. I have purchased some parts to build a small, cheap 800W RIMS tube. I would like to add a cheap PID (my pin td4), indicator lights, 2-way switch for the element, and maybe mount my PWM for my 12V pump inside the box also. I don't want an e-stop.

I have been looking around and so far I have come up with some parts based off of my limited knowledge:

PID: http://www.amazon.com/dp/B0087O6S2A/?tag=skimlinks_replacement-20

Switch: http://www.ebay.com/itm/310569446042?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Contactor: http://www.ebay.com/sch/i.html?_sac...urpose Contactor&rt=nc&LH_FS=1&_udlo&_udhi=13

XLR3 Female Plug: http://www.ebay.com/itm/2x-3P-XLR-C...=US_Audio_Cables_Adapters&hash=item5d47e0c646

I will also be using switchcraft or another speakon type of power adapter for all of my power needs.


My issue is that I have a spa panel with only 3 wire heading into my box, so I have no usable neutral for my 120v 800W element, 12V fan or 12V pump. Maybe in the future I will have 4 wire setup, but not for a long time. Instead I figured I could run 240 and 120 separately into my box. I do this now in way, I have my 1500W element in my HLT running into a 120 (gfi) outlet while my 240 from the stove runs into my box.

Could I run a cable from 120 outlet to my box also and use that to power my ac-dc converter and 800W element? Any issues doing this? I am going to leave the HLT separate until I can afford another PID setup. I figured I would have to leave out the main power selector switch until I have 4-wire coming in. When that happens I will likely just re-wire the whole box. Eventually I want a 2 PID, 1 PWM, 1-2 12v pump system.

Anyway I hope I have been clear enough so you get the idea. Any diagrams, concerns or advice are more than welcome.

 

[processhead]

This would not be my first choice for setting up a system.

The reasons against doing this are mostly about safety and adding another layer of complexity to your control wiring.

Having said that, there is no reason why it would not work as long as you keep the separate power sources isolated from each other and connect them only to their respective loads.
Really you just want to connect them as totally independent systems that are located in the same panel.

If it were my choice, and the existing 220 volt wiring had the ampacity for your new RIMS, I would be looking at a way to run a neutral conductor from the breaker panel to your brewing panel.

Since you are considering the expense and the trouble to run a 120 volt circuit, why not adding the appropriately sized neutral conductor? It would make your panel operate on a single power source and be easier to wire and maintain, IMHO.

 

[cjgenever]

If your 220 is dedicated, as many are, you can use a combination ground/neutral as long as the neutral is insulated and of Ample size. Ie... most ranges come pre wired for a three prong outlet. The neutral and ground are bonded at the terminals. As long as there is nothing else down line that could become energized you are good. The neutral and ground separate at the gfci in your box. If your gfci is at the main then you could run some 14/2 (or other size as appropriate) and use all three conductors as the ground or neutral.

To code? NO.

Dangerous? YES, IF ANYONE UNFAMILIAR WITH WHAT YOU HAVE DONE MESSES WITH IT.

the physics of electricity can be safely applied without meeting code. Code makes things stupid proof(ish).

I would tape the lines together and label everything A LOT, everywhere.

That said, this does not meet code and I can not recommend it. In fact, this was all a joke. Don't do it.

I run a 50a line to a sub panel (spa disconnect). It has four slots. One had a 50a gfci two pole. [EDIT: 30a two pole gfci] The other two are 20a single poles running directly to gfci outlets mounted in a metal box mounted to the sub panel enclosure. The sub panel is kept at a distance from the wet use area. I can bond ground and neutral at the panel because it is the only thing on the line.

I am obviously not an electrician so do not take anything I say as gospel. As anything else you deal with, you are the final deciding factor on your safety. Don't do anything you are not sure is absolutely safe as you are responsible for your safety, not me.

Good luck!

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[Mojzis]

This would not be my first choice for setting up a system.

The reasons against doing this are mostly about safety and adding another layer of complexity to your control wiring.

Not my first choice either. Could you go further an tell me what's dangerous? I'd like to be safe..

The idea was that the 240 and 120 are 100% separate, but in the same box that is all. No mixing the power lines...i'm not that dumb. I wanted 120 to power my pump, 120 element and fan. 240 will only be run to the 240 pwm.

If it were my choice, and the existing 220 volt wiring had the ampacity for your new RIMS, I would be looking at a way to run a neutral conductor from the breaker panel to your brewing panel.

Not possible in this present situation as far as my understanding goes... I cannot run 4 wire to my setup.

Since you are considering the expense and the trouble to run a 120 volt circuit, why not adding the appropriately sized neutral conductor? It would make your panel operate on a single power source and be easier to wire and maintain, IMHO.

I'm not running another 120 circuit, there is an existing 120 circuit I currently use for my HLT. So there is no expense there. Setting up another or altering the 240 3 wire setup already in place can't be done as its not my house.

If I just have to wire up a separate RIMS box I will, no big deal besides time. I just figured I could start making my larger control box with what I have and eventually switch over.

 

[kenh]

With my rig 120V and 240V are separate only because I already have a 120V outlet on the basement wall behind my brew stand, but the only thing that's 120V is my MARCH pump. Power is run to an electrical box mounted on my brew stand with a light switch that turns the pump on and off.

I have a 3 wire 30 Amp circuit without a GFI run for all the 240V stuff and I would have no problem running my pump between one hot leg and ground if the outlet had not already been there. That's how the stove and dryer circuits are run in my house and the lights in both are 120V. My stove and dryer don't have GFI breakers and I doubt that yours do either.

A lot of list members keep preaching GFI, Safety, GFI, Safety and I agree that safety is extremely important. But what's more important is proper wiring and I learned from my brother in-law that a GFI won't protect you from bad wiring or from being electrocuted by touching a combination of the wrong two things. A GFI also won't protect you from scalding water which is why the kids are never allowed in the basement when I'm brewing.

 

[jeffmeh]

Search on here for the 3 in, 4 out GFCI spa panel wiring. You don't get a true ground, but it is quite safe (same principle as every 240v/120v dryer used in the past), and you do end up with H-H-N-G at your control panel. Make the spa panel a portable device that plugs into your 240v outlet, and you are not subject to the electrical code as you are not changing any house wiring.

Is it as ideal as having a true ground running from your main panel? No, but it is the next best thing if you cannot accomplish that.

 

[P-J]

Search on here for the 3 in, 4 out GFCI spa panel wiring. You don't get a true ground, but it is quite safe (same principle as every 240v/120v dryer used in the past), and you do end up with H-H-N-G at your control panel. Make the spa panel a portable device that plugs into your 240v outlet, and you are not subject to the electrical code as you are not changing any house wiring.

Is it as ideal as having a true ground running from your main panel? No, but it is the next best thing if you cannot accomplish that.

This:

 

[Mojzis]

Great to hear. That will be much easier than what I had in mind. Thank you all for your help.

 

[cjgenever]

I guess I wasn't being clear. That is what I was saying. Your ground and neutral are bonded at the sub panel, but separate after the gfci.that gives you three conductors to the main and allows the gfci to provide protection@both 120v and 240v. I would do that if I had a 50a breaker. Mine is only 30a, so I needed to add a few extra parts. I base my projects on what I have on hand to reduce costs and I had some gfci duplex outlets and 20a breakers. With all that connected I can use all 50a my circuit provides.

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[cjgenever]

My issue is that I have a spa panel with only 3 wire heading into my box, so I have no usable neutral for my 120v 800W element, 12V fan or 12V pump. Maybe in the future I will have 4 wire setup, but not for a long time. Instead I figured I could run 240 and 120 separately into my box. I do this now in way, I have my 1500W element in my HLT running into a 120 (gfi) outlet while my 240 from the stove runs into my box.

The third wire is your neutral. It should have its own insulation. The gfci adds its own neutral that is separate from the bonded ground/neutral coming into the box. That allows it to monitor operations for both 120v (hot/neutral) and 240v (hot/hot). Just remember to try to keep your legs balanced.

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[Mojzis]

I got what you were trying to say after I saw the diagram.

Keeping the legs balanced would mean not overloading one leg with all of the power my 120 hardware needs?

 

[cjgenever]

Just split the loads as well as you can. Remember, a 240 load will load its amperage on both legs. A 120v load will affect only the leg it is on.

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[Mojzis]

I have more questions. I'm looking into how I will wire up the box now that I can have 4 wires heading in. Based off of one of PJ's diagrams I was planning on using a 10A DSPT switch to control my pump and the 10A switch for the 800W rims tube. However since my pump is 12V, what does that mean for the switch? I have a panel mount current converter I was going to use for the pump and fan but I'm not sure how I can wire it up with the switch.

Can a two way switch work fine under 12v?

 

[Mojzis]

Have I done the wiring correctly? I tried following a few of PJ's diagrams to match up what I could. I also attached a pdf so someone can show me changes that may need to be made. Feedback would be great.

View attachment Control Box Wiring.pdf

 

[augiedoggy]

Just split the loads as well as you can. Remember, a 240 load will load its amperage on both legs. A 120v load will affect only the leg it is on.

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this wont make as much difference as you would think unless you were using close to the recommended max load carriying capacity of the wire/ circuit ... if your only running one element on a 30a circuit then you have like 8-12 amps to spare... so if your pump or fan is running off the 120v theres still reserved juice on tap... just dont expect to run a fridge, pumps and blowers and such all off one shared leg.. if you do have a lot of 120v devices, youll need to split the 120v hot leads up amongst two plugs and be sure NOT to use one of those 2 into 6 adapters on that outlet or it will combine the two hot leads from each... hopefully I explained that well enough to understand.

You only need one 12v powersupply for the fan and pump (just get one around 1.2a or higher... otherwise from what I can see it looks good. I wired two pwm circuits for two 12v pumps like your planning and they have worked great so far.
oh yeah, you might want to run the opposite hot lead to power yor 12v power supply and pid if your powering it on 120v vs 220. just to help split up the load on one hot element a bit. (I would run the pids on 220v since I read they are sometimes unreliable at 120v depending on manufacturer)

 

[Mojzis]

The second power supply is so the fan runs independent of the pump switch. I wanted the fan to be running once the main power has been turned on. I didn't see another way to only use one 12v power supply because its after the switch. I have a few of those supplies anyway. I believe they are rated to 2-3 amps but i'll have to double check.

And i'll use the other hot to power the PID and 12v supplies. For the PID, just replace the neutral with another hot line?

Also, do I need another 1A fuse before the RIMS switch? Someone suggested I also put a 15A fuse on the hot lines before each outlet in case of a fault. I'm wondering if thats necessary..

 

[cjgenever]

Low voltage toggles are cheap@radio shack or big box. That would allow a single step down transformer.

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[cjgenever]

It is good practice to use a fuse or breaker where your supply amperage is higher than the maximum amperage of the device. it will almost always make no difference, but the one time it does the results are catastrophic.

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[cjgenever]

this wont make as much difference as you would think unless you were using close to the recommended max load carriying capacity of the wire/ circuit ... if your only running one element on a 30a circuit then you have like 8-12 amps to spare... so if your pump or fan is running off the 120v theres still reserved juice on tap... just dont expect to run a fridge, pumps and blowers and such all off one shared leg.. if you do have a lot of 120v devices, youll need to split the 120v hot leads up amongst two plugs and be sure NOT to use one of those 2 into 6 adapters on that outlet or it will combine the two hot leads from each... hopefully I explained that well enough to understand.

You only need one 12v powersupply for the fan and pump (just get one around 1.2a or higher... otherwise from what I can see it looks good. I wired two pwm circuits for two 12v pumps like your planning and they have worked great so far.
oh yeah, you might want to run the opposite hot lead to power yor 12v power supply and pid if your powering it on 120v vs 220. just to help split up the load on one hot element a bit. (I would run the pids on 220v since I read they are sometimes unreliable at 120v depending on manufacturer)

I agree the balancing doesn't make a huge difference unless you are maxing things out. I always tend to build anything with maximum potential in mind. in which case balancing is important to me. if I have unused potential current I will wire my box so I can tap that in the future if need be.

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[cjgenever]

I don't see any big reason to choose 240 or 120 for the PID. if there has been known flaws then that would be a good reason. I suppose I would just run it on 120 if it didn't cause any balancing issues because 120 has less potential to arc. voltage is needed to overcome the insulating properties of atmosphere.

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[cjgenever]

nothing jumps out at me on the schematic. but take that for what it's worth because I'm looking at it on a phone. hard to keep up with everything when scrolling all around.

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[augiedoggy]

I don't see any big reason to choose 240 or 120 for the PID. if there has been known flaws then that would be a good reason. I suppose I would just run it on 120 if it didn't cause any balancing issues because 120 has less potential to arc. voltage is needed to overcome the insulating properties of atmosphere.

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I know your not using one but the cheapy rex c100 pids are terrible on 120...its a coin toss as to whether it will even power up and work and that voltage.

as far as the 12v powersupply I wired switches after the main 12v supply ...it just splits off to the fan,pwm#1 and pwm#2 power boards...My supply powers both 24v and 12v devices. I do have a main Dc power switch that activates my element relays (24v dv coils) and 12v power...
if this is off my pumps fan and ssr/elements wont work which prevents things from overheating... also I'll know before its too late it the 12/24v supply stops working and my cooling fan with it. you can see my poorly laid out panel below (im going to replace and rearrange things a bit now that I'm done adding things.)(im replacing that rex pid with another mypin td4 I picked up and have better on/off rotory switches for the pumps now.

 

[Mojzis]

It is good practice to use a fuse or breaker where your supply amperage is higher than the maximum amperage of the device. it will almost always make no difference, but the one time it does the results are catastrophic.

Ok, I might just do that as extra precaution. Thanks!

I agree the balancing doesn't make a huge difference unless you are maxing things out. I always tend to build anything with maximum potential in mind. in which case balancing is important to me. if I have unused potential current I will wire my box so I can tap that in the future if need be.

I'll keep that in mind. I'm going to eventually add my 1500W HLT to the control box also. However I won't be running BK and MLT simultaneously.

I know your not using one but the cheapy rex c100 pids are terrible on 120...its a coin toss as to whether it will even power up and work and that voltage.

as far as the 12v powersupply I wired switches after the main 12v supply ...it just splits off to the fan,pwm#1 and pwm#2 power boards...My supply powers both 24v and 12v devices. I do have a main Dc power switch that activates my element relays (24v dv coils) and 12v power...
if this is off my pumps fan and ssr/elements wont work which prevents things from overheating... also I'll know before its too late it the 12/24v supply stops working and my cooling fan with it. you can see my poorly laid out panel below (im going to replace and rearrange things a bit now that I'm done adding things.)(im replacing that rex pid with another mypin td4 I picked up and have better on/off rotory switches for the pumps now.

So the TD4 should be okay on 120?

I see how you have yours wired with 12v, neat concept. Do you have a wiring diagram I can view?

Thanks for the pic of your panel. Why is one PID huge and the other much smaller? I'm hoping the TD4 isn't that big...

 

[augiedoggy]

Ok, I might just do that as extra precaution. Thanks!



I'll keep that in mind. I'm going to eventually add my 1500W HLT to the control box also. However I won't be running BK and MLT simultaneously.



So the TD4 should be okay on 120?

I see how you have yours wired with 12v, neat concept. Do you have a wiring diagram I can view?

Thanks for the pic of your panel. Why is one PID huge and the other much smaller? I'm hoping the TD4 isn't that big...

no the td4 is the small one to the right... the TA7 is the big one... I bought it before doing my homework along with the Rex.
I don't have a diagram. I may take more pics and do a build thread eventually.

 

[Mojzis]

Could you give me an idea how you wired up your TD4?

I'd like to add it to my diagram so I am less confused in the future..

 

[augiedoggy]

Could you give me an idea how you wired up your TD4?

I'd like to add it to my diagram so I am less confused in the future..

I will have to take mine apart and look... I know I found the answers myself on this site when I searched... I may try to replace my rex pid tonight and will snap a few pics.

 

[Mojzis]

I thought about what you were saying about using only one power supply and sat down and figured about how to set it up. I also added the correct (at least in theory) wiring for the pt100 probe I ordered. Please point out an error in the diagram if you see anything wrong, as I will begin wiring it up this way as soon as the parts come in from the corners of the earth.

Thanks for everyone's help.

 

[Mojzis]

Got this running today to brew a batch. Only problem I had was getting the PID to keep the correct temp. I tried autotuning but I should have done it with grains instead of just water. Tried to hit 155 and it would hit 156 then drop to 154 then shoot up to 160 and back down again. A few more batches maybe and i'll get it worked out.

Thanks for the help!

 

[augiedoggy]

Got this running today to brew a batch. Only problem I had was getting the PID to keep the correct temp. I tried autotuning but I should have done it with grains instead of just water. Tried to hit 155 and it would hit 156 then drop to 154 then shoot up to 160 and back down again. A few more batches maybe and i'll get it worked out.

Thanks for the help!

try changing the "I" setting in the service menu to 1 from 240...Brumetuer suggested it in another thread and it has worked well to prevent the pid from overshooting so far for me today as I'm brewing an ESB now...

 

[Mojzis]

Very cool. I'll give it a shot