I bought a bundle of these old power distribution units (PDUs) from a commercial building that previously housed a small picture frame manufacturer and was being remodeled, don't know how they were being used there. I assume they were intended for server-type rack installations but I can find nothing about Antennacraft (RadioShack) catalog no PPL660F10A online, or any Antennacraft PDUs for that matter. PDU overview PDU label

The "cord" appears to be standard flexible metal conduit, with black/white/green 12AWG stranded THWN/THHN wires inside. Wires are labeled: "12 AWG (UL) E63039 TYPE THHN OR THWN OR MTW GR II VW-1 600V OR AWM 1316 AND 1408 ---- C(UL) TYPE T90 NYLON OR TWN75" (popped off the fitting where it attaches to check them out).

The connector has the ungoogleable code "AMP 90 9/16" stamped on it - AMP being the brand name, but good luck searching "AMP plug". It's keyed and the terminal positions are asymmetric. The outside of the main "box" shape measures 0.32" tall and 1.85" wide, with 0.15" width terminals. Riveted onto the conduit so I can't remove it to look for more P/Ns without damaging it. connector side view connector end view

My intention was to mount these in a few convenient locations in shop spaces, such as on a workbench or a wall. The three methods I came up with for the electrical side are:

  1. Find the mating side of the weird connector for sale, and either hardwire it somewhere (if the connector allows it) or make an adapter to a regular NEMA 5-15P plug. What is that connector, though?
  2. Chop off the weird connector and put a 5-15P plug directly on there to use it like any old power strip - Do 5-15P plugs that attach to FMC exist or are they a no-no for some reason?
  3. Chop off the weird connector and run the wires into a junction box with a FMC fitting. Probably isn't covered by the UL listing (since it's probably not listed for permanent installation) but is there anything necessarily unsafe about this option?
  • @EdBeal I can remove the third suggested option (probably not compliant), but the first two are specifically asking if they are legal options. It's a UL-listed device so I'm assuming there's a legal way to use it.
    – CameronSS
    Jul 8, 2022 at 23:25
  • But the last no not possible with plug in devices
    – Ed Beal
    Jul 8, 2022 at 23:26
  • 1
    @CameronSS It's UL-listing is based on plugging it into the appropriate power distribution system with the installed plug.
    – JACK
    Jul 8, 2022 at 23:28

1 Answer 1


These are for cubicles

They are power distribution strips meant to be part of cubicle assemblies, like offices have.

It is exactly what it looks like: a Legrand Plugmold style power strip, FMC conduit, and a proprietary plug that matches the busway used for distribution. Note the 7-8 pin positions in the plug with only 3 used. That is so the harness can be "punched down" to one or more of several circuits.

But that is run of the mill FMC, and you don't need the special plug... except to tie into the busway. UL requires that if you plug into that busway, you use a listed plug for that purpose, i.e. that plug. But you're not, so who cares?

The assumption that this whole thing was factory built and was not field assembled, may be incorrect. How would they know how long to make the FMC?

The FMC is exactly what it looks like. Now here's the trick: you may think of it as flexible cordage. You may want to use it as flexible cordage. But it's not. It's in-wall building wiring.

And it can only be used for that. If you are permanently installing this like a cubicle, go for it. If it's to be flexible cordage, get real cordage.

If for building wiring, I see no problem with attaching the FMC into a connector for that, and going into the knockout of a metal junction box. That is how it is normally used.

  • Yep, my intention was to clamp these down to something solid - would only be moved around if I was redoing the whole shop space. So I'm not sure why I wanted to keep a plug anyway, it's not like it would be that hard to remove them from a junction box if I had to. Assuming 12gauge wire in the rest of the circuit, I believe it could be hardwired to a 20A breaker? Which would allow me to use 20A plugs elsewhere on the circuit.
    – CameronSS
    Jul 9, 2022 at 22:59

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