In the USA 14 gauge is only good for 15 amps. It can not be used legally on a circuit that is protected by a 20 amp breaker.
It doesn't matter that a GFCI is involved.
Several different factors must always be considered when deciding the correct wire size to use:
To get the right answers refer to the Wiring Codes or Regulations for your locality. (Town/State.)
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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
It won't cause any damage, but the circuit breaker will trip before the GFI. In essence, the GFI will theoretically never trip, even if you push the "test" button. If your breaker is rated at 15 amps, then that is all the circuit will hold. The GFI becomes an expensive but ordinary 15 amp receptacle.
No, this is dangerous. Never, ever, mix wire sizes in the same circuit. The 14 gauge wire can catch on fire before the 20 amp breaker will ever trip. On a 20 amp breaker use only AWG #12 wire throughout the entire circuit.
Yes, that would be safe as long as the circuit breaker remains 15 amps. The 20 amp receptacle is more robust (and more expensive) than necessary, but that's OK.
Does it surge past 120?? Drops are due too the fact that there are too many outlets or devices on one line. Trace the line that you have a voltage drop in and find which breaker it is, if the line that comes off the breaker is a 12 gauge wire and the breaker is a 15amp breaker you can put in a 20amp breaker. If the line is a 14 gauge line then you must leave the 15amp breaker in place and remove a device from it.
A 20 amp circuit with #12 gauge wire will work in any event but if the nameplate recommends a 15 amp circuit then #14 gauge wire on a 15 amp circuit is sufficient. In either case you will have a double pole breaker and your equipment may not require a neutral. Always run a grounding conductor.
A breaker box circuit fuse? Check the wire size. 14gauge use 15amp. 12 gauge use 20 amp.
You need a 60 amp breaker.
Minimum size is 10 gauge with a 30 amp breaker. To be safe I would install an 8 gauge with a 40 amp breaker.
No. A 20 amp breaker needs 12 gauge wire.
Does it surge past 120?? Drops are due too the fact that there are too many outlets or devices on one line. Trace the line that you have a voltage drop in and find which breaker it is, if the line that comes off the breaker is a 12 gauge wire and the breaker is a 15amp breaker you can put in a 20amp breaker. If the line is a 14 gauge line then you must leave the 15amp breaker in place and remove a device from it.
A 20 amp circuit with #12 gauge wire will work in any event but if the nameplate recommends a 15 amp circuit then #14 gauge wire on a 15 amp circuit is sufficient. In either case you will have a double pole breaker and your equipment may not require a neutral. Always run a grounding conductor.
A breaker box circuit fuse? Check the wire size. 14gauge use 15amp. 12 gauge use 20 amp.
Assuming the wires are the correct gauge for application and breaker you use black and white wires as hot. Put red electrical tape on each end of white wire and connect red and black to the breaker output and bare wire to ground lug in panel. At receptacle connect black and red to hot contacts and bare wire to ground lug.
You need a 60 amp breaker.
14 gauge will handle it with a 15 amp breaker. If you use 12 gauge use a 20 amp breaker.
You could if it fit properly in the connector, but it would be massive overkill since you only need 12 AWG wire. You also have to make sure the load can physically accommodate that larger size wire. Every so often someone will replace an electric cooktop witha gas one. All of the new gas cooktops require a 110v outlet. The old electric cooktop may have been run with a 50 amp breaker (and probably 6 gauge wire) In order to convert this 220 v circuit to a 110v circuit we change to a 20amp breaker. Depending upon the brand of breaker sometimes the wire will fit into it. If not, we splice on a short piece of 12 gauge wire and then connect to the breaker.
Minimum size is 10 gauge with a 30 amp breaker. To be safe I would install an 8 gauge with a 40 amp breaker.
If your question is can you use a #6 flexible SOOW cord and put a 30 amp plug on it, then yes. The breaker that feeds the receptacle that the cord will plug into can be no larger than a 30 amp breaker. What limits the cord capacity to 30 amps is the ratings of the plug on the end of the cord.
30 amp breaker with #10 gauge copper wire
Not legally because the rating of the 30 amp receptacle would have a 50 amp breaker ahead of it. If you reduced the feed breaker to 30 amps and still use the #6 wire, this would be within the electrical code rules.