Supplying power -- 3-prong range outlet?

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ryanvp123

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So, I've been doing a lot of research and figuring out what all I need to buy to get started on my Kal/theelectricbrewery.com clone. I am at the point of figuring out how to supply power to the rig.

The issue is, my only 240V outlet is an old 3-prong, 50amp Range outlet which is usually plugged into my stove/oven. The way I understand it, the 3 lines in that receptacle are hot/hot/neutral, no separate ground. I am renting, so it's really not an option to route new outlets, new breakers in the main panel, etc.

So the actual questions here:

1) Is GFCI protection even an option from this outlet? I was planning (if it is possible/safe) to buy a spa panel and hook it up between the outlet and my control panel.

2) How do I deal with the no-ground issue? Could I run a 3+ground wire from my control panel, to the spa panel, then to the 3-prong receptacle? Would it be safe, useful, and/or "legit" to connect the ground and neutral at the range plug (and only there)?

3) I really don't have any desire to run back to back batches or both elements at the same time, would it be ok to run a 10gauge/30amp feed from the wall and have a 30 amp slow-blow fuse (or fast acting?) wired up at my power input in the control panel? I'm going to be somewhat far from the outlet, so would love to not have to buy a massive amount of 6ga wire..

Thanks in advance for your help. And thanks to the community for the massive amount of information already out there!
 
If you cannot run a ground wire (or rewire completely with 4 wires), your best bet is to get the spa panel GFCI, and you can wire it to make it functional as a GFCI with 4 wires out to your control panel. What you CANNOT do safely, is use one of the hot legs and the neutral for 120V power in the control panel, so you should make your control panel 240V only. You would have to draw 120V from a separate circuit, and that would need its own GFCI.

Some people bring a 120V feed from a separate circuit into the control panel as well as the 240V. That is feasible, but always bear in mind that you need to disconnect two power inputs to completely de-energize the panel.

Good luck with it.
 
Thanks for the input! Good to know that I am at least not dead in the water. Running a separate 120V circuit could be doable, I suppose. I have a GFCI'd 120V plug just next to the stove anyway, it's just another extension cord and adding extra terminal blocks for the 120V circuit, i suppose.

Just for my curiosity's sake though, what is unsafe about using the hot and neutral for 120V? From some more reading I've been doing, the impression I get is that the developed ground is legitimate, or just as much so as the pre-1995 3-pronged outlet is?

Also, I'm still a bit stumped on the best way to deal with the 50amp 240V supply and 30amp cable/control panel. Would it be OK to run 10gauge wire for everything and just have a 30amp fuse on the 240v circuit?
 
If you cannot run a ground wire (or rewire completely with 4 wires), your best bet is to get the spa panel GFCI, and you can wire it to make it functional as a GFCI with 4 wires out to your control panel. What you CANNOT do safely, is use one of the hot legs and the neutral for 120V power in the control panel, so you should make your control panel 240V only. You would have to draw 120V from a separate circuit, and that would need its own GFCI.


Good luck with it.

I dont believe this is correct. PJ has been showing that you can bring 4 wires into your control panel and still be able to use 120v pumps. Im not the expert but i suggest we try to find the real answer to this.
 
Yeah, it's no problem, and a damn good idea to put in the GFCI spa panel, and there is no problem I know of drawing 120V from hot to neutral. That's the whole point of having the neutral...to have 120/240V. If there was no intent to derive 120V there would be two hots and ground instead of two hots and neutral.

That said, the part about three wires into the spa panel and four wires out has me in a bit of a concern. Not that I think it's any less safe, but currently I'm of the opinion that it's not within Code to "make" ground out of neutral in this case. It's false advertising if you will.

Anyone with a code reference to justify that I'd appreciate the reference to examine it and admit wrong if that's the case.
 
Also, I'm still a bit stumped on the best way to deal with the 50amp 240V supply and 30amp cable/control panel. Would it be OK to run 10gauge wire for everything and just have a 30amp fuse on the 240v circuit?

That's a good question. Certainly I plug things into 15A or 20A circuits that don't have 14ga or 12ga power cords. Whether or not that changes with what might be considered a dedicated circuit I don't know. Probably another one of those Code deals that is why there are Master electricians. :)
 
What you CANNOT do safely, is use one of the hot legs and the neutral for 120V power in the control panel, so you should make your control panel 240V only. You would have to draw 120V from a separate circuit, and that would need its own GFCI.

This is incorrect - you can safely us a hot leg and the neutral for 120V. How do you think your stove is powering its 120V oven light?

The ONLY difference between 3 wire & 4 wire is with 4 wire, a separate gound is run from the panel (the 4th wire). If you were to chase the wires all the way back to the main incoming panel you would find that both are tied together by the sheet metal of the box. With 3 wire, the white wire or shield serves as both neutral and ground.
 
If you want your GFCI to work, your pot (and other exposed metal) cannot be connected to the neutral wire. It must be connected to a earth safety ground.

A GFCI won't detect a short in your pot if the pot is grounded to the neutral.

But, if you don't have a safety ground (green wire), you still need to tie the neutral to any exposed metal, like your pot. At least you have a chance that if there is a dead short in your pot the breaker might trip in your pot; but, it might not. If it doesn't, you'll be the first to know about it.
 
This is incorrect - you can safely us a hot leg and the neutral for 120V. How do you think your stove is powering its 120V oven light?

The ONLY difference between 3 wire & 4 wire is with 4 wire, a separate gound is run from the panel (the 4th wire). If you were to chase the wires all the way back to the main incoming panel you would find that both are tied together by the sheet metal of the box. With 3 wire, the white wire or shield serves as both neutral and ground.

The neutral goes through the GFCI, the ground does not. This is VERY important to understand if you expect the GFCI to work.
 
The neutral goes through the GFCI, the ground does not. This is VERY important to understand if you expect the GFCI to work.

I understand but the discussion was about a 3 wire range circuit & it's ground, not a GFI protected ground. The statement was made that you can't safely use neutral and one of the hot legs of a 3 wire range circuit for 120V and this is not true.
 
You guys rock, thanks so much for the help!

So what I get from all this is as long as I don't intermingle the ground/neutral myself after the proper wiring in the spa panel, I should be golden as far as that's all concerned, right? With proper grounding to the "created" ground, of course.

Also, I found some 10gauge inline fuse holders that I can pop a 30 amp fuse in to protect all my equipment, since it's all 10gauge wiring at most. Should I just put one on one of the hot legs? Or do I need one on both hot sides?

I put in a load of online orders today. Expect another build thread starting in the next couple weeks, if y'all aren't sick of them by now ;)

Cheers!
 
I understand but the discussion was about a 3 wire range circuit & it's ground, not a GFI protected ground. The statement was made that you can't safely use neutral and one of the hot legs of a 3 wire range circuit for 120V and this is not true.

Gotcha. Right you are. In fact, I do just that. Sorry, I just skimmed to the end of the thread.
 
I understand but the discussion was about a 3 wire range circuit & it's ground, not a GFI protected ground. The statement was made that you can't safely use neutral and one of the hot legs of a 3 wire range circuit for 120V and this is not true.
Cheers.!!

Absolutely right on the money.

It all depends on the 'year' that the outlet wiring was installed. Dryers and ranges contain both 120V and 240V components. Therefore the power delivered is 240V and neutral.

Once past the building wiring that terminates in the outlet, what you do is not subject to the current NEC rules.

There have been many posts that I have made, and illustrated, on how to set up a proper GFCI protected plug in circuit layout using a GFCI Spa Panel. It is ALL according to code and designed to protect you.

It is ALL within code regulations and just plain common sense.

I'm done.
P-J
 
It is ALL according to code and designed to protect you.


I'm done.
P-J

Other than "deriving" ground from neutral in the spa panel is of no benefit to safety. Might just as well keep with a 3-wire receptacle downsteam of the spa panel and bond everything to that neutral rather than spend the money on a 4 wire and the illusion of dedicated equipment grounding.
 
Correct, here are the rules:

Existing 3-wire wiring is legal - it conformed to code when it was installed.
3-wire ground and neutral are the same going into the spa panel.
Ground exiting the spa GFI breaker ties to all exposed metal parts, including your brew controller panel & brew pot.
Neutral exiting the spa panel along with either hot leg is used for 120V circuits.
 
Also, I found some 10gauge inline fuse holders that I can pop a 30 amp fuse in to protect all my equipment, since it's all 10gauge wiring at most. Should I just put one on one of the hot legs? Or do I need one on both hot sides?
Cheers!

This would be for 120V stuff like your pumps? You only need to fuse the hot leg you are drawing from. But more important - don't fuse the neutral.
 
Ground exiting the spa GFI breaker ties to all exposed metal parts, including your brew controller panel & brew pot.

Equipment ground has ZERO to do with GFI.

In fact, if you replace a non grounding two wire 120V receptacle with a GFI receptacle with grounding, you must plug the grounding prong or label the receptacle "non-grounding". Those decals and instructions are provided with GFI receptacle. Installing GFI isn't a substitute for equipment grounding but agreed it does considerably mitigate risk of electrocution.
 
Equipment ground has ZERO to do with GFI.

In fact, if you replace a non grounding two wire 120V receptacle with a GFI receptacle, you must plug grounding prong or label the receptacle "non-grounding". Those decals and instructions are provided with GFI receptacle. Installing GFI isn't a substitute for equipment grounding but agreed it does considerably mitigate risk of electrocution.

Equipment ground has everything to do with GFI. By tying your brew panel & brew pot to ground you provide a instant path to ground in the event that either of these touch live power & this will trip the GFI.

And GFI or not, you should ground any exposed metal. I don't know about you but my brew area has a lot of water standing around....
 
This would be for 120V stuff like your pumps? You only need to fuse the hot leg you are drawing from. But more important - don't fuse the neutral.

Well, yes, I'm fusing the 120V stuff with a 7amp fuse as well, but what I'm talking about is my 240V line going into the control panel.

Since I'm coming from a 50amp Range outlet, and all my equipment & wiring is 30amp/10gauge, I'm planning to put those inline fuses in to basically downgrade my 50amp outlet to a hard max of 30 amps, since I have no 30 amp breaker (50 amp in the main panel, 50A on the spa panel). I should just have to put a 30A fuse on one leg for that purpose, yes?
 
Equipment ground has nothing to do with the function of GFI. GFI merely measures current in vs current out. If there is a difference greater than ~6mA then GFI trips, regardless where it goes. Could be a water puddle, damp concrete, or whatever, but it's not contingent on equipment ground.
 
Well, yes, I'm fusing the 120V stuff with a 7amp fuse as well, but what I'm talking about is my 240V line going into the control panel.

Since I'm coming from a 50amp Range outlet, and all my equipment & wiring is 30amp/10gauge, I'm planning to put those inline fuses in to basically downgrade my 50amp outlet to a hard max of 30 amps, since I have no 30 amp breaker (50 amp in the main panel, 50A on the spa panel). I should just have to put a 30A fuse on one leg for that purpose, yes?
If you want to limit incoming current to the panel it should be done with a 2 pole breaker so that if one side "blows" or trips, the other side is also shut off. I believe something like this would be a better choice.

http://paneltronics.com/ip.asp?op=product_search&product=206-083S
 
Correct, here are the rules:

Existing 3-wire wiring is legal - it conformed to code when it was installed.
3-wire ground and neutral are the same going into the spa panel.
Ground exiting the spa GFI breaker ties to all exposed metal parts, including your brew controller panel & brew pot.
Neutral exiting the spa panel along with either hot leg is used for 120V circuits.

OK, I may have messed up the earlier post. If I understand what you are saying:

1) You can use the neutral after the spa panel GFCI for 120V circuits.
2) You cannot safely bond ground and neutral together again after the GFCI
3) You must not hardwire the spa panel, as it would then be subject to the current code and not in conformance because ground and neutral are bonded together after the main panel

So if the neutral on a 120V circuit were disconnected in the control panel, the GFCI would detect the imbalance and trip. Out of curiosity, what would happen if the GFCI were to fail under those circumstances? However unlikely, could I have a condition where my ground was carrying current as the neutral in the panel?

Sorry for any confusion here.
 
...
So if the neutral on a 120V circuit were disconnected in the control panel, the GFCI would detect the imbalance and trip. Out of curiosity, what would happen if the GFCI were to fail under those circumstances? However unlikely, could I have a condition where my ground was carrying current as the neutral in the panel?
...
Just a suppose:
Your wiring is new, installed by an electrician with all permits, inspected and in accordance with today's code. It is a 4 wire circuit with a GFCI breaker in the mains panel.

What happens if the GFCI breaker fails?

Think about it.
 
1) You can use the neutral after the spa panel GFCI for 120V circuits.
True, just like you can safely use neutral before the GFCI. It's the return path for your 120V devices.

2) You cannot safely bond ground and neutral together again after the GFCI
True, if you were to bond ground and neutral together after the GFCI the GFCI would not perform correctly. With a 120V device drawing current it would trip all the time. With a 240V device drawing current it may not trip fast enough to protect you.

The GFCI senses current differences between the three legs. So, if current between the two hot sides and neutral average out with a small margin of error the GFCI stays on. This is true with 120V or 240V drawn from a 240V circuit. If the current does not average out there must be leakage to ground and the GFCI trips. The ground actually bypasses the GFCI & is used to bond all exposed metal surfaces, like your stove top or your brewery equipment, to earth ground.

3) You must not hardwire the spa panel, as it would then be subject to the current code and not in conformance because ground and neutral are bonded together after the main panel
The spa panel is designed to add GFCI protection to a new or existing non-GFCI circuit. I could be wrong but I don't believe there is anything in the NEC making a permanent install illegal.

So if the neutral on a 120V circuit were disconnected in the control panel, the GFCI would detect the imbalance and trip. Out of curiosity, what would happen if the GFCI were to fail under those circumstances?
If the neutral were disconnected at the mail panel and you were running all 240V equipment you would not see any difference. BUT if you were running a mix of 120V & 240V devices the 120V devices would see odd voltages and would likely be damaged. The GFCI would not trip.

However unlikely, could I have a condition where my ground was carrying current as the neutral in the panel?
Any 120V devices will pass current back to the main panel through the ground / neutral because it's the same circuit. But after the GFCI, there will be no current on ground. If there were it would be because of an unbalance and the GFCI should have already tripped.
 
The spa panel is designed to add GFCI protection to a new or existing non-GFCI circuit. I could be wrong but I don't believe there is anything in the NEC making a permanent install illegal.

In fact I would presume it's generally intended for permanent installation. However, I think the point is not that, the point is then NEC may well apply differently to the fixed/permanent installation than what may apply under the guise of cord & plug connected equipment.
 
Any 120V devices will pass current back to the main panel through the ground / neutral because it's the same circuit. But after the GFCI, there will be no current on ground. If there were it would be because of an unbalance and the GFCI should have already tripped.


Maybe things would be more clear to talk in terms of grounded wire (neutral) and grounding wire (equipment ground). When just the term "ground" is used it's unclear in some cases what's really meant.
 
Thanks guys. I do believe I understand at this point (or now I know enough to be really dangerous).

I was under the impression if doing permanent wiring it would have to conform to current code (and subject to local inspections, etc.), and that bonding neutral to ground is verboten except at the main panel.
 
Maybe things would be more clear to talk in terms of grounded wire (neutral) and grounding wire (equipment ground). When just the term "ground" is used it's unclear in some cases what's really meant.

I wouldn't think of the neutral as a ground. When there is a lot of current running through it, there might very well be an AC voltage present (I*R drop across poor connections or wire resistance).

Also, if there is a GFCI upstream on the ckt, the neutral isn't directly tied to earth ground anyway. You might not always know if the ckt is GFCI protected.

Green is ground. White is neutral.
 
Thanks guys. I do believe I understand at this point (or now I know enough to be really dangerous).

I was under the impression if doing permanent wiring it would have to conform to current code (and subject to local inspections, etc.), and that bonding neutral to ground is verboten except at the main panel.

Any additions must conform to current code. If the house wiring had to conform to current code when a wiring addition was done, most houses in this country would have to be rewired when something was added. And adding this spa panel to a unused stove circuit is adding to existing wiring.
 
So the spa panel, going from 3 wires to 4, would conform to the current code? I thought not, because are not neutral and ground bonded together in the spa panel? I was not referring to the preexisting wiring.
 
Any additions must conform to current code. If the house wiring had to conform to current code when a wiring addition was done, most houses in this country would have to be rewired when something was added. And adding this spa panel to a unused stove circuit is adding to existing wiring.
Well said.

Just another prospective: If the Spa panel is installed as a plug in device, the building wiring is not altered at all. Therefore no inspection required and no violation of any code.

Almost every dryer or range is a 240 + 120V device. Through about 2007 the power feed was done using a 3 wire feed.

Just saying.
 
So the spa panel, going from 3 wires to 4, would conform to the current code? I thought not, because are not neutral and ground bonded together in the spa panel? I was not referring to the preexisting wiring.

That's exactly what this panel is - it converts a non-protected 3 or 4 wire circuit into a GFCI protected 4 wire circuit.

SPA Panel.jpg
 
As thargrav said you could change the 2P50A breaker (if you feel comfortable doing so) to a 2P30A and the circuit would be protected at 30 amps and use the spa panel for GFI protection.
In some of the old 240 VAC installations they used SEU cable (two insulated conductors and one un-insulated). The current in the two legs balanced out and the resultant current was just about zero. I don't think you can use the "neutral/ground" (bare conductor) wire for 120VAC circuits, because it becomes an un-insulated current carrying conductor which is a no-no. You'd have to convert the other conductor to the neutral and use the bare wire as a ground.
 
The third conductor in the SEU cable, which is the braided cable wrapped around the other two, is intentionally sized large enough to handle quite a bit of current. "From memory", if aluminum, the two main conductors are 6 gauge and the braided wrapper is 8 gauge. Also, because of the outer covering, the braided part is considered an insulated current carrying conductor. It's also the safety ground for the stove.
 
I wouldn't think of the neutral as a ground. When there is a lot of current running through it, there might very well be an AC voltage present (I*R drop across poor connections or wire resistance).

Also, if there is a GFCI upstream on the ckt, the neutral isn't directly tied to earth ground anyway. You might not always know if the ckt is GFCI protected.

Green is ground. White is neutral.

The tems I used previously are accurate.

By NEC, the official term for the "neutral" is grounded conductor, and the equipment/safety ground is officially called the grounding conductor.

These terms are used by NEC to avoid ambiguity.
 
The tems I used previously are accurate.

By NEC, the official term for the "neutral" is grounded conductor, and the equipment/safety ground is officially called the grounding conductor.

These terms are used by NEC to avoid ambiguity.

Hmmm. I don't think that's a good way to avoid ambiguity. Grounded conductor, grounding conductor.

But I do believe you. Thanks, I learned something tonight!
 
That's exactly what this panel is - it converts a non-protected 3 or 4 wire circuit into a GFCI protected 4 wire circuit.

It doesnt really convert anything except adding the GFI (which I fully agree is good). Merely adding a GFI does not allow you to make equipment grounding from the neutral (grounded conductor).
 
Hmmm. I don't think that's a good way to avoid ambiguity. Grounded conductor, grounding conductor.

But I do believe you. Thanks, I learned something tonight!

Its certainly much better than just plain "ground", which as you read these threads, is used loosely for any number of things, whereas grounding wire means one thing and one thing only.
 

Every range and dryer sold today is setup for three wire or 4 wire because they have to be compatible with houses wired before 1996. And just about every dryer and range sold today has a mix of 120V and 240V components.

In a dryer - the heating elements are 240V, the controls may be 240V or 120V, the motor may be 240V or 120V.

In a stove - the oven light is 120V, the controls can be 120V or 240V.
 
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