So up in the attic guest room of our century home, there’s a baseboard electrical outlet that looks like a light socket (see picture below). I’m not sure what exactly to call it, and various Google searches don’t turn up anything like it (probably because I don’t know what it’s called). When we moved in, it had one of those screw-in adapters like people screw into actual light sockets; I removed that immediately.

I very much want to replace the outlet with something from this millennium, but I admit to being a little wary. I’ve successfully replaced old two-prong outlets with GFCIs before, but I’m not sure if this is likely to be significantly different. I do expect 15A knob-and-tube wiring, and I’m not expecting a ground wire, but I’m wondering if there’s anything else I should be ready for before I start in. Or if this is one of those “oh crap, dude, don’t go anywhere near that thing without a certified electrician with thirty years of experience!” situations.

What say you, DIYstack?

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EDITED TO FOLLOW UP: here are some pictures of the wiring and units. First, the wiring after I disconnected the receptacle and unstrung the leads from the gang box.

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The gang box itself is solid metal, stamped “STEEL CITY” in the back. The receptacle unit’s body appears to be porcelain, both in look and feel and because it chipped pretty easily when my screwdriver bit slipped off a screw. Here are the front and back.

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The manufacturer appears to have been Bryant, as per the stamp on the upper left corner and also the fancy engraving on the contact tongue in the back of the socket itself. If I’m not mistaken, that lower right corner is stamped “660W250V”.

I tried just splicing the two wires together, both with a Wago lever splice and a traditional twist-cap splice, and in both cases got an instant circuit-trip as soon as I closed the breaker switch. So I reconnected the receptacle unit and that went fine; it’s powered to the proper levels and no circuit tripping happens.

I was planning to replace this myself with either a (non-grounded) GFCI or possibly a non-GFCI three-prong outlet, of which I have a few lying around, but now it feels like that’s outside my competence zone and I should bring in a licensed electrician. Thoughts?

  • It would not be any trouble/danger to turn off the breaker and take the screws out to see whats inside. Is it switched ? what do you want to go in its place ?
    – Alaska Man
    Commented Apr 5, 2020 at 2:22
  • It isn’t switched, and I was thinking a no-equipment-ground 2-gang GFCI or else a 2-gang two-prong receptacle. Commented Apr 5, 2020 at 2:32
  • 2
    This is a socket for a screw-in receptacle. That is apparently what you removed. You're right that what you'll find back there is knob and tube wiring and probably no ground. Open it up and have fun.
    – HoneyDo
    Commented Apr 5, 2020 at 3:52
  • 2
    These were super-popular 100+ years ago - see plugsocketmuseum.nl/NorthAm3.html for the history. See this answer about knob-and-tube for modern use of the wires behind it.
    – Moshe Katz
    Commented Apr 5, 2020 at 4:52
  • 1
    Can you turn off the breaker/pull the fuse that makes this not-hot-any-longer, take the cover plate off, take the device out (without unwiring it!), and post clear photos of the inisde of the junction box please? Commented Apr 5, 2020 at 5:23

1 Answer 1


This appears to be an ancient Edison-screw-receptacle

What you have appears to be an ancient sort of receptacle, from the days when people put Edison screw bases on the end of cords because standard NEMA receptacles weren't a thing yet. I'd put a new single-gang old work box in there with the correct tubing/bushings for that old K&T wiring, and then fit a 15A GFCI receptacle at that location; just be careful to make sure you don't get hot and neutral mixed up!

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