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I'm adding new lights to my basement ceiling. I pulled out the old messy tangle of wires and ran new romex, but was missing the 4ft needed to reach the last box. I reused the old wire. Will this pass inspection?

Both old and new wire is 14/2 copper with ground. New wire has plastic sheathing (NMD90), old wire appears to have paper strands wrapped around the conductors with a dark/black outer coating (NMD-7).

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You can reuse old cable if a physical inspection reveals all of it to be in good condition. It's inside walls, so it's not like it's had 30 years of sunlight baking it. However if it's roached anywhere, into the trash cash-for-scrap bin it goes. Shiny copper is worth over $1/pound.

However, you can't splice except at a junction box which must remain directly accessible. It can be behind a cabinet door that opens, but it can't be under a screwed-down plywood access panel or anything that would require tools or destruction to get to. (the junction box cover doesn't apply, obviously).

I for one don't have any problems with splices properly executed in a grounded steel junction box.

  • the 4 ft spans the last 2 light's boxes, so all good there :) I'm surprised to hear that screwed-down plywood doesn't count as accessible though! – jpx Oct 26 '19 at 14:52
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    If you don't know there's a box there, you can't find the box by just looking for it - which is basically what "accessible" means in this context. If you have to know that you have to unscrew a particular bit of plywood to get to it, someone who does not know (or does not remember) can't be expected to find it there. – Ecnerwal Oct 26 '19 at 16:02
  • "You can't splice" means, "by law, you can't splice"? – jrw32982 supports Monica Nov 1 '19 at 18:27
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    @jrw32982 is there a difference? This often comes up when people think Code is perfunctory, unreasonable or superfluous. That is not true. In almost all cases a Code requirement has bona fide safety reasons and safety is worsened if it is disregarded. For instance, unserviceable splices buried inside walls are known to perform poorly and start fires. – Harper - Reinstate Monica Nov 1 '19 at 18:40
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    @jrw32982supportsMonica It is a safety issue and a legal issue. It is a rite of passage in the electrical business to doubt whether an NEC rule really improves safety... and then learn more and discover yeah, it really does. Do that for a few dozen rules and you learn to stop doubting :) – Harper - Reinstate Monica Nov 1 '19 at 19:02
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There are two types of NMD-7. I am assuming the NMD-7 you are referring to is a vinyl-coated cable and not the cloth-covered cable. We cannot vouch for the shape the cable is in without being on site.

I am not saying you can't use it, but may cause a few problems.

First, obviously, it is used therefore it does not have the same life as the new cable so it is likely to cause a problem before the rest of the system.

Second, how are you handling the splice? It needs to be maintained, meaning it needs to be protected and available for maintenance, usually in a box and cover.

From a contractor's point of view it would not be allowed since it would pose too much of a liability.

In short if you are installing a new circuit, and to insure a quality installation, you should install all new components with a minimum of splices. It usually pays off in the long run.

As far as passing inspection, I don't believe any of us can give you an answer since that is a decision of the AHJ, and we don't know their way of thinking. I would suggest you contact them and discuss it. Believe it or not they are there to help you. You pay their salary and they work for you as well as the community they serve.

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    the 4 ft spans box to box. No splices outside a box! – jpx Oct 26 '19 at 13:57
  • @Nij If its just a typo then jump in and fix it with edit. The poster will get a notification and can revert if it changes their meaning. – Criggie Oct 26 '19 at 22:16
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    @Criggie Edits must be at least six characters unless they affect the title or only affect tags, and I didn't have time to check for other potential edits. I've now done so, with several other points. I think I might know how privs on SE work... ;) – Nij Oct 26 '19 at 22:29
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One thing I'd be cautious about: copper alloys typically work-harden and become brittle. If it's been bent around a lot in the course of installation and removal, there is the possibility of hidden cracks forming where you'll never see them. These cracks will have increased resistance and become hot spots when current is flowing. If you handled the wire carefully during removal and re-installation, it should be fine, but any sections that have been repeatedly bent and straightened should be suspect.

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