Electrical – How to safely get power strip to desk in center of room

electricalnecwiring

I can't even tell if this is a stupid question anymore.

I have a desk in the center of a 12′ × 13′ room, on which I would like to have a power strip to power a computer and other, less power-hungry devices. After my first, definitely stupid and dangerous idea (to run an extension cord under a rug), I started looking into the NEC and the UL White Book and the difference between "relocatable power taps" and "multioutlet assemblies" and now I feel like I have no idea what is safe.

Here's what I think I know:

  • Extension cords are not to be used as a replacement for permanent wiring. I want this setup to basically stay in place for the next one to five years, so extension cords seem to be out.
  • A power strip—erm, "relocatable power tap"—can maybe be used as permanent wiring if it contains a fuse or circuit breaker and if no tools are needed to remove it. But it still can't do things like go in walls (I'm a renter; I'm not looking to break through any walls anyway).
  • "Flexible cords" (which includes the cord of an RPT?) must not be attached to "building surfaces." (But does that prohibit attaching cords to walls/ceilings using hardware designed for this, like cable staples large enough not to put pressure on the cord, or ceiling hooks like what I see used with lamps sometimes? Neither of these methods require tools to remove; is that relevant?)
  • Power cords should not be covered because they are designed assuming they can be cooled in the open air. (But does that prohibit floor covers like this, or raceway sections like this?)

I should also note that my computer has a 1200W power supply, and while I've never actually measured it using nearly that much power, to have a margin of safety, I want to assume that it could basically start drawing 10A at any time. Therefore, whatever powers it should both be rated for that level of current (ideally the full 15A that the room's circuit can provide) and also be installed in such a way that resistance heating in the power cord isn't a fire hazard.

So it seems like I have three general approaches:

  • Run a power strip with a circuit breaker and a long power cord across the carpet up to my desk. Try not to trip on it. There is a virtue in simplicity, but hey, everyone trips sometimes.
  • Same as above, but cover it with something safely (i.e., by means that prevent tripping, damaging the cord, and up-to-15A currents causing anything to heat to an unsafe temperature). I'm not a huge fan of the floor cord protectors I've seen (they seem like they'll be obnoxious to move when vacuuming), but if it's the right thing to do, I'll do it.
  • Run a power strip with an even longer power cord (I'm looking at this one) up the nearest wall, across the (drywall) ceiling, and drop down onto the desk. Barring electrical issues, this is my favorite approach, but it leaves me with a lot of questions about whether there is a code-approved (or not technically code-approved but still assuredly safe) way to affix a power cord to walls and ceilings. The codes all seem to forbid this generally but things like that Wiremold raceway and ceiling hooks for lamp cords seem to indicate otherwise (and if those are safe, I don't see why appropriately-sized cable staples wouldn't be also). If the Wiremold raceway is the way to go, I also can't tell if there's a meaningful difference between just covering the power strip's existing cord with raceway versus doing a more extensive Wiremold installation, which seems to involve tapping into an outlet with a starter box, running a different kind of wire through the gateway, placing a receptacle… on the ceiling? And running the power strip down from the ceiling receptacle? Is that actually safer?

What should I do, and which of these various questions and concerns are actually safety issues versus misunderstandings or excessive pedantry?

(If relevant, I live in Connecticut, USA.)

Best Answer

Appliance and extension cords are called cordage.

Use the right stuff

The issue with cordage as a substitute for permanent wiring of the structure is not a “don’t do it” issue: it’s a “use the right stuff” issue.

“The right stuff” is appropriate wires designed for permanent use in structures, including appropriate physical protection. For instance instead of stapling cordage to a wall, you should use surface conduit with THHN wires inside.

Of course, that requires a transition from the THHN to the cordage at some point. That happens at a junction box, e.g. with a receptacle in it; the easiest way to transition from hardwiring to cordage.

Consider a pendant for center-of-room power

A pendant is a piece of special cordage with high quality strain relief on both ends (think the Chinese finger puzzle webbing) that drops straight down from a box on the ceiling down to a junction box suspended in midair by the cordage. You then plug into that recep.

Probably best to use a fan-rated ceiling box. This can be a surface-mount box (you’ll need to find the studs) which in turn can be supplied via surface conduit such as Legrand Wiremold.

The suspended box would probably be a metal box rated for a fan, since they are tough and built to endure tugs on the pendant.

If you want to be very fancy, you can have the pendant lock into a locking connector like a NEMA L5-15.

That PC power supply is a terror

That “1200 watt” PC power supply is a gigantic beast made for gaming. The “1200 watt” figure is the actually useful DC output of the supply; it is NOT the AC mains input — that is affected first by the efficiency of the unit and by the power factor.

   X (actual power drawn) x efficiency% x PF% = useful power out.

The “850 watt” power supplies actually draw 10 amps. So I could see a 1200 watt supply drawing 16A or 17A.

I would revisit the necessity of such an ostentatiously large power supply.

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