Circuit tracing help

[6270_Productions]

If someone mentioned this already, I apologize.  But you could put an inductive ammeter on it to see if there’s a load on it.  

If you want to monitor it long term, disconnect it, splice on a good cord with plug, and plug it into a Kill A Watt on another circuit.  Make sure the cumulative values are zero, which it may do automatically whenever you unplug it but reset it if it doesn’t, then come back in a week and see how many kWh have accumulated.  If any.

One advantage of the KAW is that if it’s reading a load, you can look at Power Factor (PF) and see if it’s less than 1.0.  If it is, then the load is either a motor or something with a transformer, like fluorescent lights, or a power supply, like (maybe, since I’ve never tested one ) a computer.  If it is 1.0 or very close, it’s a resistive load (like a heater) or incandescent light bulbs.  Dividing W (watts) by VA (volt-amperes) gives PF.  If the Kill A Watt is showing any load at all at the time you look at it, of course. It doesn’t accumulate volt-amp-hours like it does watt-hours, unfortunately.

If no watt-hours accumulate, consider seasonal loads, like roof/gutter heater or some office window air conditioner somewhere or a water tank heater or doghouse heater or something like that.  Maybe even a small shed with security light that’s not on or burned out, where a single 120V circuit is common and may not carry current until it’s dark out or someone turns the light on.

Edit:  Oooh, almost forgot - don’t forget fire alarm or smoke detector circuits.  Exit signs.  Stuff like that, since it’s a public space.  Things like exit signs are so common that you may not even notice if they’re not lighted with the circuit off.

^

That is some really good information.  

[daddo]

Run a new dedicated circuit to each heater.

[goaliedad]

I would put a clamp on amp meter on the line in question- if there is a draw you have to find it. If zero draw I would turn it off and put a big note on the breaker box- someone will let you know what it is feeding. You mentioned the line in question goes to the apartment- could it be something in there, or did you check everything there?

[Scouter]

Thanks for everyone's suggestions.

I ended up running a camera down from the attic, not the easiest, but it worked. I wish the cameras on these things were bigger and easier to control (cabling is too flexible), but I found it (took an hour). Turns out that there was an outlet that was put in before they put the cabinets were installed, it was hidden behind the cabinet. I opened the side of the cabinet so that there is access to the plug. Since that is the only thing on the circuit I can use that as the breaker for the ladies room, and leave the vestibule and the classroom on the existing circuit.

Now I get to try something new. There is no slack in the line, so I have to tap into the line to add the new run. Found this at Lowes, an inline tap sans a junction box.

https://www.lowes.com/pd/TE-Connectivity...r/50205335

[lift mechanic]

Install a junction box some where you can get to it and then run a new wire to where ever you want from that junction box.

[Scouter]

Install a junction box some where you can get to it and then run a new wire to where ever you want from that junction box.

I would have to use two junction boxes so as to extend the wire, there is no play in the wires to allow me to reconnect them in the box.

[MarkSingleton]

If it were me, I would use the junction boxes. Much safer.

This line is for a heater, right?

Going to draw a lot of power through that line.  A seven dollar
crimp on connection does not sound like a good permanent
solution.

NOT an electrician.  Which makes me more paranoid about this
stuff.

[MstrCarpenter]

If that receptacle hasn't been used since the cabinets were installed , and couldn't have been used 'til they were removed (barring your handy work of course), can you just delete the recp. and use that as the feed for the ladies room?

[TDKPE]

If that receptacle hasn't been used since the cabinets were installed , and couldn't have been used 'til they were removed (barring your handy work of course), can you just delete the recp. and use that as the feed for the ladies room?

I was thinking the same thing.  If it was buried behind a cabinet, it's not legal anyway (box not accessible), and not used of course, so why not just cut the line in the attic and extend it to where it will be used?  15A is a bit light for a heater (assuming it's 15A), but that depends on the heater's rated wattage, of course.  Fixed in place heaters require a circuit with 125% of the rated ampacity, which is 1440W max on a 120V 15A circuit. 

But it can be reconnected in the panel for 240V, using the same wiring (assuming modern wiring, 300V rated at least, with equipment ground), which will double the wattage of course.  No neutral required for a 240V (only) heater; just an equipment ground, which I'm assuming is present in the cable. 

I'm not a big fan of inline splices either, even though they're UL listed.  Two boxes and a length of NM (or whatever type the cable is) is not a big deal.  If the receptacle is unused and inaccessible anyway, I'd cut the line wherever it's most convenient, put it into a box, and run an extension to wherever you need it, and also mark the cut end as to its final destination hidden behind a cabinet.  I'd also mark the receptacle that its source was cut (and where), in case someone wants to move it and re-energize it at a later date.  Then put the cabinet back together. 

With a heater now on that circuit, it probably should not be powered off its original circuit anyway, and can't be if you reconfigure it to 240V.  But at least you will have given the next guy (or gal) a clue as to where to look for cut end of what used to power that dead receptacle outlet, should someone uncover it some time in the future and want to do something with it. I wired the 3 ft electric baseboard (they're typically 250W/ft) in my office with 14/2 on a 240V 15A circuit, because 240V is what was available at the BORG and what's needed once you get over 5 ft.

Edit: Unless this circuit is not for a heater.  I'm not exactly clear precisely what will be on it in the end.