My contractor recently added a 20-Amp circuit to my kitchen while he was remodeling it. He explained that the circuit was 20-Amp, and the non-GFCI outlets he installed all have the little horizontal line on the side, which I always thought was the designator for a 20-Amp outlet and 20-Amp circuit. That is, I thought that the “little extra line” is used to plug in a 20-Amp device which has a different plug configuration from a 15-Amp.
And I even found answers here and here that confirm what I always thought: if it has the line it is 20-Amp, and if it doesn’t it is 15-Amp.
But I noticed my contractor installed a couple of GFCIs that don’t have the extra line on the side of the plug. I mentioned this to him, and he explained that the GFCI outlets he installed really were 20-Amp outlets, they just don’t have that extra line.
I thought he was trying to save a few bucks by installing a 15-Amp outlet and assumed I wouldn’t know or notice, but he quickly reassured me by pulling off the plate cover and showing me the side of the outlet where it was stamped in the plastic “20 Amp.” So now I’m confused. What does the little line on the outlet mean? Is there a difference between a 20 Amp outlet with or without the extra line?
BTW, in trying to research this question before posting, I discovered that even if he had installed 15-Amp outlets on a 20-Amp circuit, it would have still been code, as answered by these questions:
I live in the USA, for purposes of wiring codes and outlet types related to this question.
Update
I took apart the outlet again and see both the 20 Amp the contractor pointed out originally, plus a 15 Amp on the other side. I agree with the answer that this is a 15 Amp receptacle with a 20 Amp pass through.
Best Answer
A receptacle without that horizontal slot is only rated to supply 15 amps to a device that's plugged into it. GFCIs are no exception to this. That "20 Amps" stamp is likely stating the receptacle's pass-through rating, or the amount of current it can supply to sockets downstream of it.
There are GFCI devices with that horizontal slot available, which will supply 20 amps to attached devices, and can be found online with a quick Google for "20 amp GFCI receptacle".
You cannot plug a 20 amp device directly into any receptacle without that horizontal bar, be it a regular receptacle, or a GFCI.