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I have an newly installed, single outdoor outlet on my patio and had the electrician pipe in conduit (yep... live in Chicago.... it sucks), 12 gauge wire, and install a 20 amp GFCI a new 20 amp breaker for a dedicated circuit to this one outlet. Easy done.

The outlets are the typical 3 prong / Type B / USA style for your normal household appliance.

The outlet is used for electrical cooking on the tabletop and I know we have tripped the circuit before on an unknown outlet running two cook tops (not sure if it's 15 amps or 20 amps...).

Could you use like 8 gauge wire to carry more amps at 110V... and still use the normal household outlet? Are there code worthy / safety testing, receptable over 20amps / outlets / breaker combinations that come with a Type B plug?

So the question is, is there a GFCI, Type B outlet, that goes above 20A?

I've never seen anything like that, but we have such a goofy usage of this one outlet I've got my brain wondering now. (In retrospect, we could have a done a double gang outlet, and run two sets of 12 gauge wires -- but theoretically these two cook tops should be fine with 20A, but Mr. Conduit guy is coming back for one last outlet and we could rewire more current, I guess -- this run is really ugly already, I'm not actually sure we could fit 8 gauge across my basement to this outlet).

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    The breaker of the circuit must be rated to the lowest common denominator; in this case the actual outlet. You can run 8ga wire to the outlet, but the outlet is still rated for 20A, meaning the breaker must match 20A. A fire would be probable if you tried to pull more amps through the outlet than what it's rated for, as it then would become a fuse.
    – stevieb
    Aug 22, 2022 at 22:25
  • Yeah, GFCI receptacles have no overcurrent abilities whatsoever. In fact 15A GFCIs are rated for 20A passthru. It would be a valid (but illegal) way to GFCI protect a TT30 trailer socket.
    – Harper - Reinstate Monica
    Aug 22, 2022 at 22:45

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For good reasons, circuits do not exist larger than 20A, but you can have as many 20A circuits as you please. Well, six anyway.

You can put in a second circuit.

Because that "sucky" conduit supports up to four 15-20A circuits per pipe.

So adding a second circuit is easy street. Just fish red and gray THHN wires into the pipe and done. Or for that matter, 1 circuit can be added with 1 wire by using a MWBC (Multi-Wire Branch Circuit).

Oh, and if the circuit requires AFCI, metal conduit lets you ditch the $50 AFCI breaker and stick a $20 AFCI receptacle at the first outlet. That's super handy in this application, because it makes MWBCs easy. (with Romex MWBCs don't play well with AFCI requirements).

Don't intentionally overload circuits.

Every one of your appliances has a nameplate stating the current in amps, or power in watts or VA. Read the nameplates and know the amps. (take watts or VA and divide by its voltage). My sweetie can recite ours: 8 for the toaster, 7 or 12 for the space heater, 12 for the microwave and 1 for the fridge.

The majority of kitchen heat-making appliances are 1500 watts. (12.5A).

So if you have a "12" running and decide to run another "12", well, that's you choosing to overload the 20A circuit.

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  • Well the issue is we have some shared conduit runs across 3/4's of the basement which are a little stuffed already and just got two more 12 ga lines today; the full run is not all new conduit -- Mr. Conduit came in to do a whole bunch of tricky bends and gnarly things to get the finished outlet put in .... one more pair of 12 gauge, from the sub-panel to that run may not be possible. There is a second outlet like 30 feet away, and maybe I just have to stomach an extension cord in the twice a year scenario we are running the two cooktops at once...
    – Leroy105
    Aug 22, 2022 at 22:30
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    @Leroy105 how about 1 more wire? Make the circuit a MWBC. EMT conduits can take either 9 or 10 #12, don't recall... and ground doesn't need to be one of them since the pipe is the ground.
    – Harper - Reinstate Monica
    Aug 22, 2022 at 22:32
  • I've never seen a MWBC in real life. That could maybe work, but Mr. Conduit might have his mind blown. (I'm buddies this with guy, he's just a wizard with conduit -- 10x my speed to bend conduit. Took him a few hours, it would take me a few days...) -- Harry House Inspector / Carl the Code Guy in IL... I don't know how he would feel with an an MWBC either!
    – Leroy105
    Aug 22, 2022 at 22:33
  • @Leroy105 that's OK, the pipe guy doesn't need to know what the wire guy is doing lol. Yeah I would check your conduit fill on the route of that circuit and see if you can MWBC-ify it. MWBCs and conduit play very well together because it allows you to displace AFCI to the first receptacle, hence plain breakers.
    – Harper - Reinstate Monica
    Aug 22, 2022 at 22:38
  • Theoretically, both of these hot plates are 1100W at 120V, so I am at 9.17A per hotplate. ~18.5 amps to run both. Is that within the margin of popping a 20A breaker? -- Yuck, a quick check on the internet doesn't seem too happy running a load like that on a 20 amp breaker.
    – Leroy105
    Aug 22, 2022 at 22:39
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8 gauge wire might be too big to fit for common 120 volt outlets. 10 gauge would fit, but unless it is a very long distance, usually not worth it.

There could be a problem with the cook top made for 15 or 20 amp circuits if it keeps tripping. Have the electrician check it out.

Conduits are nice to have. No worry about mice chewing cables in the wall and the wires are easy to change/pull if needed.

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    Standard NEMA 5-15 outlets on a >20A circuit would violate NEC 210.21.
    – Harper - Reinstate Monica
    Aug 22, 2022 at 22:38
  • @Harper-ReinstateMonica Kind of hoping OP wanted larger gauge in case of voltage drop, not to fit a larger breaker.
    – crip659
    Aug 22, 2022 at 22:45
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    lol I interpreted the question differently. I figured a house in Chicago, probably isn't on a big enough yard for voltage drop to ever become a factor LOL. But yeah that's a good point.
    – Harper - Reinstate Monica
    Aug 22, 2022 at 22:46
  • #8 wire on a 20A breaker still won't allow for (much) more than a 20A draw, though. The breaker will still trip to protect the wiring in the wall, not caring that it's #8 instead of #12.
    – FreeMan
    Aug 23, 2022 at 12:37

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