For the electricians...

[utopeya]

So, I'm working on an automated electric brewery (using a bunch of the stuff I've learned from these boards), and I have some questions about GFCI protection for my 4500W brew kettle.

I'm brewing in an apartment, so I'll be plugging into my range receptacle for 240V power. As far as I can tell, I have a few options, each of which comes with some difficulties.

1. Buy a spa panel with a 50A GFCI breaker, and wire it up so I can plug into the range receptacle. My main concern here is cost, really. From what I've read, there's a lot of stuff you have to do to make sure this kind of setup is up to code.

2. Buy an inline GFCI. Again, cost is a concern. The only thing I've found that doesn't cost many hundreds of dollars is this: http://www.labsafety.com/User-Attachable-In-Line-GFCI_24536740/ , and I don't know whether 20A is beefy enough. 4500W/240V = 18.75A, but 4500W/220V = 20.45A.

3. Replace my 30A breaker with a GFCI one, like this: http://doitbest.com/Circuit+breakers-GE+Industrial+Dept-model-THQL1130GFP-doitbest-sku-519332.dib . This would actually be pretty easy--my main basement panel has one breaker that powers my apartment's sub panel, so I could just switch it off from the basement and swap breakers. My only question here is whether the GFCI will play nice with my electric range.

Thoughts? Other suggestions? I'm way deeper into this than I intended to get, so anything that might save me some money without getting me killed would be greatly appreciated.


Oh, one other concern: my range receptacle is the older three-prong kind, but I opened it up and there are actually four wires running to it. I'm assuming I'll need to switch to a four-wire setup for the GFCI to do what it's supposed to do--is this correct?

Thanks so much.

 

[passedpawn]

Find a 30A 2-pole breaker online for your fuse box. It will work fine with your stove. You will need to take a good look at your breaker panel to make sure the breaker you get will fit.

This is a job you could do yourself. Replacing a breaker is a 5 minute job, but you could also kill yourself. If you have a electrician friend, or one who is handy, you might solicit his help (even before you commit to buying the breaker).

You should change that receptacle to a 4-wire. You want to ground your pot to earth GND, which is the green (4th) wire. Then, if there is a short in your pot, the GFCI will trip. With a 3-wire plug, you would tie the white (neutral) to the pot, but this will NOT trip the GFCI (It should trip the breaker, though). Anway, yes, change the plug and breathe easy.

 

[utopeya]

Thanks for the speediness. Yes, I realized after I posted that the breaker I linked is single-pole and won't work. I'll check around for a two-pole one.

 

[rudy0498]

I was able to find a used 2 pole 50A GFCI breaker for my panel on ebay for about $40 shipped. Find the brand and model number you need to fit your panel do a search. Some people probably wouldn't take a chance on it, but mine has worked just fine.

 

[jfkriege]

I went the route of the spa box, and have been very pleased. I needed a 50A circuit, and the 50A GFI breakers were very expensive.

The spa panel also means that you can take your GFI with you when you leave, and you can even take your rig over to a friends house if they have an outlet.

Joshua

 

[SweetSounds]

You mentioned that the panel in the basement has a single breaker feeding a sub panel in the apartment?

If that's the case, you don't want the GFCI breaker in the basement (Trying to protect the entire apartment) - You want it in the sub panel, as the last thing between the range plug and the panel.

Edit - I re-read the OP - Never mind, you know that already

Also, I wouldn't replace the 30 amp range breaker with a 50 amp GFCI, and change the plug to 4-wire - If your range requires 30 amps!
If your range has a fault, that will allow an extra 20 amps at 220 volts before the breaker trips!

If you have access to your apartment panel, and it's got the breaker space, you could just add your 30 or 50 amp GFCI breaker on its own. That might be the safest thing to do...

Keep in mind though - Landlords and insurance companies frown on such things!

 

[utopeya]

Thanks for the responses. I ended up ordering a replacement breaker on ebay, with the same rating as the one I'll be replacing.

I do like the portability of the spa box... maybe I'll rework things that way when I have some more funds available.

SweetSounds, the idea wasn't to replace the 30A breaker (it's actually 40A--I was mistaken) with a 50A GFCI one, but to add a 50A GFCI breaker AFTER the 40A one (in a separate spa panel that would be mounted to my rig), so that I'd still be getting the 40A protection from the original breaker, and the new breaker would only be adding the GFCI protection.

Now I just need to figure out how to wire up and program an arduino board, and I'll be all set.

 

[samc]

I'd not mess with someone else's electric panel. It's one thing to burn down or mess with your own property, screwing with another persons is a BIG mistake IMO. Even with a licensed electrician I wouldn't do it without landlords permission.

You can see why I never want to be a landlord!

 

[SweetSounds]

+1

About the only thing I would advocate is putting pigtails on a GFCI Spa panel, and plugging it into your range outlet. At least that way you aren't making changes to the structural wiring of the apartment, and you can protect yourself from shock...

From what I've read in the NEC and (FWIW) the Wiki - A GFCI will protect (Trip) from a "Phase to earth" short - IOW a "Hot to ground" short (That would be you )

From the Wiki: An RCD will help to protect against electric shock where current flows through a person from a phase (live / line / hot) to earth.

 

[prosper]

if it were me, I'd simply replace my existing 40A range breaker with a 40A GFI unit, and be done with it. Changing a breaker is extremely simple, but potentially dangerous if you don't know exactly what you're doing.

 

[SweetSounds]

if it were me, I'd simply replace my existing 40A range breaker with a 40A GFI unit, and be done with it. Changing a breaker is extremely simple, but potentially dangerous if you don't know exactly what you're doing.

That would certainly be better than a pigtailed spa panel!

At least if the breaker is in the sub panel you can attach it to the panel neutral (Even though you won't carry the neutral to the outlet, and your load)

 

[utopeya]

OK, that makes me a little nervous. Assuming all I'm doing is replacing a regular 40A breaker in a subpanel with a GFCI 40A breaker, what kind of damage could I conceivably do? The breaker I ordered is the same type as the one I'm replacing, so it will definitely fit.

Replacing a breaker seems like a fairly simple task--in what way could I screw up in a way that would cause a fire or something equally terrible?

SweetSounds: I'm not sure exactly what you're saying directly above, but the neutral does go to the outlet... it's currently tied into the ground at the receptacle, which is why I think I should separate the two out by replacing the old receptacle with a four-prong.

 

[prosper]

so - you have a 3-conductor (plus ground) 10ga wire to the kitchen? Black, Red, White and bare? Is the white conductor connected at the panel side (there should be a brass bus bar in the panel where all the neutrals from all circuits are connected), or just left floating? (The black and Red should be connected to separate poles of a 2-pole breaker)

 

[SweetSounds]

OK, that makes me a little nervous. Assuming all I'm doing is replacing a regular 40A breaker in a subpanel with a GFCI 40A breaker, what kind of damage could I conceivably do? The breaker I ordered is the same type as the one I'm replacing, so it will definitely fit.

Replacing a breaker seems like a fairly simple task--in what way could I screw up in a way that would cause a fire or something equally terrible?

You mentioned that you can kill the entire sub panel from the main breaker in the basement - If that's the case, you shouldn't be able to fry yourself.
And assuming you are capable of attaching the white wire of the GFCI breaker to the neutral buss, you should be fine.

It really isn't hard to do, and there's little risk as long as the panel is dead, and you hook it up right!

But be warned - If something does go wrong, and the place burns, the insurance company might tell the landlord they are SOL because a tenant jacked with the electrical... Not good.

 

[DeafSmith]

If I understand correctly, you will be unplugging your stove to brew, then plugging it back in later, but leaving the GFCI in the circuit. If so, you may have problems with the stove tripping the GFCI due to moisture inside the heating coils of the stove (or maybe not if the elements are used regularly). Take a look at this thread describing the problem I had when using a GFCI with my rebuilt electric drop-in range-top.

https://www.homebrewtalk.com/f51/electric-stove-coils-tripping-gfci-fyi-177924/

 

[utopeya]

Prosper: I haven't opened up the subpanel yet, but I did open up the oven receptacle, and there are definitely four wires going to it: black, red, white, green. I also don't know the gauge of the wire by looking at it, but I imagine it's thick enough to carry 40A at 240V, since that's the rating of the oven's breaker.

SweetSounds: Thanks. I think I am sufficiently nervous at this point to make absolutely sure that the thing is hooked up correctly before I power it up.

 

[utopeya]

Thanks for the information, DeafSmith. I'm glad there is at least a solution for this problem.

 

[kezgin]

personally, i'd go with the pigtail/spa panel idea for the aforementioned liability reasons plus the possibility of nuisance tripping with your stove. if i were a landlord and i had a tenant messing with the electric panel without permission, i'd be pissed

 

[utopeya]

OK, let's assume I want to set up a pigtail/spa panel. Do I need to switch to a four-prong range receptacle? I know it's safer not to have the ground and the neutral tied together, but if I wanted to not touch my apartment's wiring at all, would I have any issues? I guess what I'm asking is whether the GFCI breaker in the spa panel would work properly with only two hots and a combined neutral/ground coming into it.

 

[DeafSmith]

OK, let's assume I want to set up a pigtail/spa panel. Do I need to switch to a four-prong range receptacle? I know it's safer not to have the ground and the neutral tied together, but if I wanted to not touch my apartment's wiring at all, would I have any issues? I guess what I'm asking is whether the GFCI breaker in the spa panel would work properly with only two hots and a combined neutral/ground coming into it.

Mine works fine on my 3-wire dryer outlet. I have the incoming neutral/ground wire tied to the neutral terminal on the left side of the spa panel. The breaker pig-tail is also tied there. I ran a wire from there to the ground bar on the right side of the panel (the one that is mounted right on the box itself) then ran the output ground from that same ground bar to my stove. It trips with a ground fault (such as with moisture in the elements as I posted about above) and doesn't trip when there is no fault.

One other thing I did (I'm sure it violates every code in the book, and I can't recommend it for safety) is that I put a regular 30 amp double pole breaker in the spare slot in the panel and wired its output in parallel with the GFCI breaker. This way, if my stove is tripping the breaker because of moisture in the elements, I can turn off the GFCI, turn on the 30 amp breaker and bake the elements for a few minutes to get the moisture out, then turn off the 30 amp and turn the GFCI back on and proceed with my brew day. I do not use the stove, or even touch it while I'm running on the non-GFCI breaker!