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[bkenobi]

I have a couple boxes (on in the garage, one in the shop) that are not covered and have Romex run to them.  There is and never has been any equipment/outlet hooked up to them, they are simply coiled in the box for future use.  My question is, how do I figure out where these are hooked up (what circuit breaker) and whether they are stupidly live power.  If they are live, I assume the builder would have at least taped them, but I haven't pulled on them yet due to concern that he was an idiot.

I am looking at some circuit breaker finders online and they look like they could be helpful if the wire were hooked up to something, but I don't know if it will work in this configuration.  I suppose I could strip the ends and gator clip the tester on, but I don't like the idea of stripping live wire (seems like a bad plan).

[dave w]

 
Turn off master breaker and investgate or strip. You would have to strip for circuit sniffer anyway.

[bkenobi]

Yeah, probably a good idea to just kill the circuit for that.

I guess what I could do is kill all power, strip, connect DMM, restore power.  If there is live power, then I can kill the power again and use a circuit tracer to find where it's connected.  I suppose that would be the best case scenario really.  If it's not live, then I don't know how I'd trace it.  Any thoughts?

I think I know where it goes, but I need to verify.  I have a 20A 220 breaker labelled "Garage heat" that I don't know what it goes to.  This wouldn't be a bad location to put heat since it's next to the workbench, so it wouldn't surprise me if that's what it's connected to.  I don't know why he didn't spend the $5 to put a 220 outlet there though.  I'll just have to verify that my DMM won't have an issue with 220 power.  I don't want to pop it!  Maybe I'll stop by Harbor Freight on the way home to pick up an El Cheapo(TM) multi meter just in case.

[Noam]

How about this:
Use a non-contact voltage tester (Home Depot has them for less than 15-20 dollars) to see if it is live or not.
You touch the plastic tip of the tester to the insulation of the wire (you can test anywhere along the cable, usually), and it lights up
(and/or beeps) if the wire is live. (hopefully it isn't).
If it is dead, then make sure the ends are taped (and not shorted), and then turn on one of the breakers that is off, and then test it again with the non-contact tester. That should hopefully find the right breaker.

If it IS live, then start turning off breakers one at a time, and test each time, until you find the one that turns it off.

[bkenobi]

That's exactly what I ended up doing!  I picked up a non-contact tester from Harbor Freight this afternoon and confirmed my suspicions that the wire was live.  Worse, it turns out it was a 15A 220 circuit.  It was the same one I figured it was (labelled "garage heat" in the panel).  I'm going to put a cover over it so it doesn't pose any danger should the breaker get turned on again.  I have another box that's the same way in the shop, so I'll have to verify that it's not currently live and put a cover over the box for protection.

Thanks for the suggestions!

 

[Noam]

Before putting a cover on the box, I suggest stripping the outer insulation off the wires, and capping them with wire nuts (or at least proper electrical tape).
I also suggest putting a label, either inside or outside the box, indicating which breaker controls it.
If that breaker should remain off, you can also put a label over the breaker in the box, indicating it should not be turned on.

[bkenobi]

Right.  That what I was thinking.

I'm actually planning on spending some time and labeling all of the outlets around the house so I know what panel and breaker they are on.  I spent a few minutes starting a blueprint of the house and quickly realized that I have a LOT of outlets.  That's good for flexibility, but a pain depending on how they are wired into the panel.

Thanks again!

[Noam]

When I moved into my house in 2004, I created a map of the breaker box. However, instead of listing each device and what breaker controls it, I did the opposite.
I made a chart of all the breakers, and then listed what each one controls. Usually (but certainly not always), *most* of the outlets in a room will be on the same breaker (kitchens are a good exception to this rule). Rooms that are split among breakers are usually done so in a semi-logical manner (ex: my family room is split onto two breakers, and the line goes right down the middle).

To make sure I was getting everything, I turned off one breaker at a time, and then looked to see what it controlled. If it was outlets in a bedroom, for example, I tested EVERY outlet in the bedroom. If one was not off (I had that in every room, the outlet that had originally been controlled by the light switch was on a different breaker from the rest), I made a note, and found THAT breaker later.

This list came in handy when I was troubleshooting cross-phase signal issues. Since the chart was arranged the same way as the breakers in the box, I could easily see which outlets and switches were on the same phase as my CM15A, and also which noise-inducers. When I had a noise problem a few years ago (caused by my neighbor's CFL), it only affected one phase of my house (the one with MORE of my devices, of course!)

In commercial and office settings, I've seen labels on every outlet plate and switch cover, listing what panel and circuit number controls that device. I feel that is probably overkill for my house, and it is not very nice-looking, either.

[bkenobi]

The breakers in the house are labeled reasonably well compared to what I've seen in the past.  The problem is that I have 2 main panels with a total of 70 positions.  Not all of these are populated, but it still leaves a lot of places to read and guess interpretations.  I need a list one way or another, so I'll have to either kill one breaker at a time or check one outlet against each breaker (I have a circuit breaker finding tool now).

For instance, I have a breaker labeled "basement outlets".  Now, since this is an unfinished basement with a total of 6 outlets (3 of which right at the panels), I figured this would be a good place to verify the labeling was accurate.  Turns out, 2 outlets are on that breaker and the remaining 4 are on 4 different breakers!  I'm at a loss to understand why it was done that way, but that's how it was done...  If I were to have killed one breaker at a time till I found each of those outlets, I would have been at it for a while.  I used the breaker finder in combination with killing the indicated circuit (which was very close to perfect, only off by a single breaker once).

Either way, it's going to take some effort to map things out.  But, before I go too far, I need to draw a blueprint to mark things down on.  The one I started was not to scale so by the 3rd room it was useless.

[Noam]

I'm guessing my house is smaller than yours (since I only have one panel).
I changed all of the outlets and wall switches in the house before we moved in, I added overhead lights in the bedrooms, and re-wired the lights in the basement. I did the work myself (well, my dad and brother-in-law came over to help some), I didn't hire an electrician.
so, I needed to be sure that I knew which breaker I was working on, to make sure it was turned off, and REALLY off.
I used a plug-in outlet tester, and a second 110/220V tester (the one where the probes snap to the back, and are spaced to be used as an outlet tester). I only bought the non-contact tester a few years later.

It took a lot of trial-and-error, and it helped to have a helper to yell down to me when the lights went out in whichever room I was testing.
My house was built in 1963. Along the way, I found a bunch of stuff that was not done the way I would have liked (like the one box in the basement that didn't like up with the hole in the paneling - so they took the side off the box, and mounted the outlet right to the paneling - outside the box!). I couldn't figure out why certain circuits were broken up the way they were (side door outside lights, kitchen lights, front porch lights, front hall light, master bath, one outlet on the front wall of the master bedroom - all on the same circuit). After troubleshooting an X10 problem a few years ago, I realized it must have been because those lights (and outlets) are all in a straight line, running along the front of the house. However, I would have broken it up. If we ever end up re-doing the kitchen, I may change that, and split it up.

[bkenobi]

A year and a half ago we moved from a 1700 sqft house to a 4000 sqft + unfinished basement home.  I had a firecracker, a TM751, and an outlet with rope lighting installed in the old house.  I found out about phase coupling in that house without understanding what I was doing.  I didn't couple the phases, but I found that some outlets worked and others didn't.

The new house already had a half dozen lighting locations with X10 installed.  I decided to add a CM15A and a couple more fixtures outside.  If only I knew what I was getting into...

The biggest thing with this house is that the previous owner was the contractor on the build effectively.  He wanted to make sure there would be no issues with future expansion of anything he could ever want to do.  As a result, almost all the outlets are on a single circuit per room on on 20A breakers.  The only thing that's 15A is lighting which is shared between 1-3 rooms generally.  This is all great for power distribution, but it does make it difficult to determine exactly what the ~50 breaker labels mean exactly.  For instance, on is labeled "Outlets den, down stairs hall".  There are actually 3 areas that could be considered hallways down stairs though.  It turns out, that hallway that the label points to is a single outlet outside the study/den/office (each nomenclature is used in different locations on the panel).  Uggg...

I'm not going to complain though.  It's nice knowing that the circuits are not overloaded and running a vacuum + hair dryer won't pop a breaker.  Heck, my last house had a single outlet in the garage (before I fixed it anyway) whereas this one has nearly a dozen.

[Noam]

Mapping out a large house, with a lot of breakers, is a big task - no matter how you tackle it.
I suppose you could try and tackle it from the breaker end, or from the device end. Both will take lots of time, and a partner (and maybe a pair of cell phones of walkie-talkies) will help a lot.

Start with a drawing of the house, and mark each device location (switch, light, outlet, hard-wired appliance, etc).

Testing from the "breaker" end, you would turn off one breaker at a time, and then test to find what devices go out. Label those on the map, and then move on to each breaker, one at a time.
At the end, any un-marked devices on the map need to be re-tested, to figure out which breaker controls them.

Testing from the "device" end, you would go to one device at a time, and check to make sure it has power (a plug-in circuit test is handy for outlets). Have the assistant turn off one breaker at a time, until that device goes out. Mark it on the map, turn the breaker back on, and move on to the next device.

You could also do a combination (doing the first method for most of it, and the second method for any "mystery" devices).

Before doing the test, I would recommend unplugging anything that might be damaged (or annoyed) by repeatedly cutting the power (like computers, A/V equipment, HVAC - turn off the thermostat, and/or the shutoff switch on the unit, refrigerators, etc.

It will probably take at least a few hours to do, but you shouldn't have to do it again (unless you make major electrical changes without documenting them well).

Once you are doing that, I suggest marking which phase each breaker is on (most breaker boxes are split so that every other row (of two breakers) is on the same phase, while the alternates are on the other phase. Most breaker boxed are mounted vertically (with two vertical columns of breakers, and lots horizontal rows of two breakers each). Some breaker boxes are mounted horizontally, so the "columns" are actually the ones that alternate between the phases.

Even with a phase bridge/coupler/repeater, there is still potential for problems affecting one phase more than the other, so knowing how the phases are split in your house can help.

With two breaker panels, you might have additional issues. Depending on how they are wired (is one simple any extension of the other, or is it a separate feed from the transformer?), you may need a coupler/repeater/bridge in each one, and possibly connecting the two. There are other people here who would be better at answering that question than I am.

[bkenobi]

I've been talking via email with Jeff Volp about the inter-connectivity of the panels.  I spoke to my local PUD engineer about how my house is wired, and they indicated that the vault in front of the house feeds 400A into a box in the house with a pair of current limiting transformers which then feeds 200A to each main panel.  I'm not clear exactly what's inside the box inside the house, but it appears that the two panels SHOULD be connected.  Jeff suggested the possibility of needing to couple the two panels with an XPCP.  Here's how I would connect them if I go that route.

• neutral from either panel
• hot from panel 1 (either leg)
• hot from panel 2 (either leg)

I'm going to test signal strength on more circuits just to be sure that it's a problem with the whole panel-to-panel and not just something on a circuit or two I've missed.

[Brian H]

From your description.
It sounds like the street feeds a 400 amp service. That is connected to two 200 amp transformers inside the house.
Feeding two 200 amp panels.

Transformers many times are poor X10 couplers so your added tests of communications between the panels. May yield more data.

[bkenobi]

That is what I was given as a description.  It's only $20 for an XPCP, but I want to make sure that I need one before I install more equipment.  I'm not going to chase a symptom instead of finding the problem!