There's a space between my hearth and the wall that I can run coax cable through to a TV but it is too tight to get an extension cord through to that TV. It is only about 1/2 inch wide; the hearth was originally designed to be freestanding, but has been screwed to the wall to improve its stability.

I'm thinking of cutting a standard extension cord and re-splicing it on the other side. But of course this rubs me the wrong way.

What other options do I have that are safe? Maybe there's a low-profile type of extension cord that is designed for this kind of thing?

  • 2
    Ugh. Are you trying to run an extension cord through a wall? Commented Dec 9, 2015 at 3:49
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    It's generally a Bad Idea and a code violation to run an extension cord through a tightly confined space. It's probably a worse idea when you don't know how warm that space gets when the fireplace is in use. Seek another solution.
    – keshlam
    Commented Dec 9, 2015 at 3:52
  • No, @ThreePhaseEel. Behind a hearth. Thanks for the attention. I hope the snark I'm detecting is a misinterpretation on my part. I'll assume you are just asking for clarification.
    – Rap
    Commented Dec 9, 2015 at 3:54
  • @keshlam. Wow. Heat from the fireplace. I seriously hadn't considered that. Thanks for the input. +1 on your comment.
    – Rap
    Commented Dec 9, 2015 at 3:56
  • Is this hearth of yours a freestanding unit, or something mounted into the building structure? Commented Dec 9, 2015 at 4:01

2 Answers 2


There are many reasons to not use extension cord or plug strips for certain applications. But setting those aside and assuming you understand the ins and outs of proper extension cord applications....there is a sane way to deal with the situation of the "tight spot".

Assuming you purchase a reasonably decent extension cord such as:

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Do not cut and try to splice back together the cord itself. Instead cut off the end of the cord right at the plug...

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Now feed the cord through the "tight spot". Then provide a new end for the cable by attaching an appropriate replacement plug assembly.

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  • 3
    First of all, you should never cut the end off an extension cord. Flexible cords and cables cannot be used as permanent wiring, so if you have to cut the head off, you're probably using it wrong. Second, extension cords are rated, listed, and labeled as an entire unit. If you remove the end, the little UL stamp on the cord is void. The cord is damaged, and is garbage no longer fit for use.
    – Tester101
    Commented Dec 9, 2015 at 11:42
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    As I said "if you have to cut the head off, you're probably using it wrong.".
    – Tester101
    Commented Dec 9, 2015 at 12:53
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    Field assembled extension cord sets . NEC 240.5(4) Are allowed if the cord is 16AWG or larger and components are listed. the circuit must have a OCPD of 20Amperes or less (circuit breaker)
    – Ed Beal
    Commented Dec 14, 2015 at 18:19
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    This is a good and perfectly valid solution. It isn't a "permanent" installation, it's merely indefinite. That type of replacement cord plug is used by tens of thousands of contractors daily in conditions much harsher than a living room. If installed correctly, according to the instructions, they're perfectly safe (and probably more secure than "UL listed" cord ends in many cases). My $.02.
    – isherwood
    Commented Jan 8, 2016 at 14:31
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    In doing rental cleanups, I've found it amazing how many of those indefinite solutions become permanent. The final arbiter is always whether the insurance claim after any incident where this is found is denied. Commented Jan 8, 2016 at 17:57

Check your hearth, but it'll be tight!

Provided that the hearth is rated for zero clearance to combustibles in back, UL 127 (the standard for manufactured fireplaces) limits the temperature rise on surfaces intended to be in contact with building material to 90°F above ambient. Considering that building wiring materials are rated to 194°F and you need to have some margin for wire heating and the minimums of derating (we can't derate below 15A here assuming a general purpose branch circuit on a 15A breaker), you're limited to a wire temperature of 167°F maximum or an ambient temperature of 77°F.

NM cable can survive 90°C exposure, but needs to be protected from physical damage, and conduit's too chubby for the job. However, you can use 12/2 NM (due to the need to derate the ampacity of the cable -- a 12AWG/90°C wire can handle 30A, but we are derating it to 15A instead) in a suitable surface raceway (less than 1/2" deep, and rated for exposure to 90°C) to make this run.

Tip: install the raceway behind the hearth first -- you'll have to sort of slide it into place, and you'll need to be judicious about where mounting clips/brackets go, as well.

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