Home Improvement → Re: Wiring Behind 70's Panelboard

Sounds easy enough.

Anything wrong electrically/code-wise about my plans? Someone told me that you can't use flex for more than 6 feet, but that person is based in Chicago where everything has to be pipe....

They are probably confused. On 20A and below circuits, you can FMC as the equipment grounding conductor. Over 6', and you have to include an actual EGC.
In some cities, they don't allow flex over 6' period, and only allow it for fixture whips.
This goes back to the earlier thread with cities / municipalities adding their own little quirks.

I wouldn't use flex, as it's a pain in the ass. If you are allowed to use MC or AC, I would use that instead.

Would AC-90 work? I mention flex because I have 250' of 1/2" I bought at a firesale price.

Since your location says New York, NY - I would assume this is in NYC? You should check the NYC codes; especially under type-FMC uses permitted & prohibited. Not sure about the flexible conduit length (simply because I never had need to look it up, as I would never do such a thing. Hideous, IMHO.) Also, if you're running it over a ceiling; not sure how you plan to secure & support it properly at the code required lengths. Its usually a lot easier to run type-MC or conduit over drop ceilings.

For another thing, you say the run is 100 feet long. Better consider using 10 AWG, or at least think about doing a voltage drop calculation. 3% is the maximum voltage drop allowed on branch circuits, as per the NYC electric code, for most types of buildings.

As for placing a 15A fused disconnect on the circuit; then, the way I see it, makes the upstream portion a feeder. I would bet there's an NEC requirement against placing receptacles on a feeder. (Again, something I have never looked up, as its something I would never do.) Sorry, sk1939, but in my opinion the whole thing sounds like what started as a mess, is only becoming worse.

Actually it's in MD, NYC was my last location when I travel for work. I bought a 50' roll of AC cable and am in the middle of putting that in, through the joist similar to how the original BX is run.

I would consider it, but it's rather pricey which is the problem.

"1 conductors per phase utilizing a #8 Copper conductor will limit the voltage drop to 2.35% or less when supplying 20.0 amps for 100 feet on a 118 volt system."

I may just abandon the whole run then, and keep powering the UPS off of the 10 Gauge cord that it's currently connected to.

I'd love to rip it all out and do it over, but it's just not feasible at this time, there's just too much stuff to move, and it's somewhat down the list of priorities atm.

Alright, I finished the run, and did it in a way I could upgrade the majority of the run back to the panel as 10 Gauge. The actual length back to the panel is about 70' if you go straight back. The current run makes an S turn. The other thing I discovered while adding this on was that there is a joist every foot and a 1/2 , which makes a new run through all that a PITA should I do it later. The bracket at the first box is there instead of a hole in the joist because of an adjacent air vent.

Also, never let relatives store things at your house without charging rent, this particular area looks like a typical storage unit hence the hesitance to remove the paneling.

I give up.

I flipped the breaker back on, and it immediately tripped. Thinking it was a fluke I flipped it back on and tripped the lighting main (good job stupid). I went back to take a look at the box, and it turn out a portion of the old downstream circuit has continuity to ground across all lines. Removing and capping that, I tried it again, again killing the lighting main (herpa derp), although the 20A breaker didn't trip. So now I checked the upstream connecting utilizing a known working extension cord and a continuity tester. It turns out that between the connection point and some two or so outlets upstream I am missing a neutral connection (what?), and that from that same outlet to the panel I get no connection between neutral and ground. What bothers me is that this circuit USED to work (or so I thought, I've used it before if nothing else), although the breaker has been off for a year or so.

When I have the panel replaced (in the next year or so), I'll have the licensed/bonded/insured sparkies run a new line to my new work (which checks out electrically), add an outlet outside, and figure out what exactly is wrong with that circuit. It's less stressful this way, and I don''t have to worry about my homeowners insurance...