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[Dennis Wiggins]

I just purchased a 1928 house.  Before I turn on power, I want need to trace back every outlet and lighting fixture to its source in the panel(s).  In doing so, I will find any wyes that have been created over the years and determine which will need AFCI and GFGIs.

I will have to verify every wire in every run, checking all grounds, before I have ComEd turn the power back on. I will also make sure that any remaining knob/tube wiring is also disconnected.

What is a good tool I can use to inject from the receptacle end (preferably all 3 wires at a time), then go to the panel(s) and find/verify it/them? 

-Dennis

[Stephen Swaffer]

A typical fox and hound is going to light everything up-especially grounds and neutrals.  Thinking outside the box, the quickest way might be to disconnect everything at the panel, then simply inject 12 or 24 VDC via a pigtail into various outlets (lighting or receptacle).  If you wire put a 12 V incandescent (RV style) into a lamp, you could quickly ID every receptacle on a given circuit.  You probably already know this, but downstream shared neutrals and bootleg grounds will play havoc with AFCI and GFCI's.

That said, I have used a Fox and Hound to trace dead wiring through drywall-if you use just the receiver I have even followed energized AC lines to find a break.

[John Roberts {JR}]

There are a number of commercial products for injecting a RF(?) signal and tracing circuits.

If the panel is not energized (and even if it was you could pull breakers) you can inject DC voltage working backwards (like a 9V battery connected to an edison plug). Plug the DC voltage into each outlet and meter with VOM to find where ever else it shows up.

Of course this will not reveal the quality of the wiring. Perhaps after identifying an outlet branch you could plug in a dead short into the outlet and measure the loop DCR at the panel. Of course don't leave these edison plugs connected to trick circuits when finished.

JR

[Dennis Wiggins]

... Thinking outside the box, the quickest way might be to disconnect everything at the panel, then simply inject 12 or 24 VDC via a pigtail into various outlets (lighting or receptacle).  If you wire put a 12 V incandescent (RV style) into a lamp, you could quickly ID every receptacle on a given circuit.  You probably already know this, but downstream shared neutrals and bootleg grounds will play havoc with AFCI and GFCI's...

That's a great idea (cheap, too!).  I have plenty of time to do this and I need to do it right.

"downstream shared neutrals and bootleg grounds" --> This is why I want to work backwards from the receptacle.  There are a scattered array of 2- and 3-wire receptacles.
 
Thanks!
- Dennis

[Dennis Wiggins]

... If the panel is not energized (and even if it was you could pull breakers) you can inject DC voltage working backwards (like a 9V battery connected to an edison plug). Plug the DC voltage into each outlet and meter with VOM to find where ever else it shows up.

... Perhaps after identifying an outlet branch you could plug in a dead short into the outlet and measure the loop DCR at the panel. Of course don't leave these edison plugs connected to trick circuits when finished.

JR

Great tips. 

Phase 1 Determine which circuits can be safely functional during reconstruction. 
Phase 2 A whole whole new panel, with correct xxCIs where necessary, before occupancy.

-Dennis

[Jonathan Johnson]

Not a complete solution:

Screw an Edison/NEMA 1-15R adapter (the kind that lets you plug a 2-prong plug into a light socket) into a fuse space. Plug in an extension cord (use a cheater plug if necessary), and now you've got a test lead from the fuse panel that you can use to identify circuits by testing continuity. The wide slot on the adapter will connect to the shell of the fuse socket, so there should be continuity between that (wide slot) and the narrow slot of receptacles on that circuit. (If there's continuity to a wide slot on a receptacle, then there's a polarity reversal.)

This will only work for the fuses with all-glass tops. The ones with metal rings on the top are likely fuses that use a peculiar base for each fuse value, and the adapter won't work in those. You may be unable to remove the socket insert, as many of them were made with barbs that prevent removal.

And it won't identify any shared neutrals.

WARNING FOR THOSE READING ALONG: Only use this method if ALL the power to the premises is disconnected. If you connect a meter set to "ohms" between two points with high voltage and current potential, you could damage your meter in surprising and dangerous ways. Regardless of circumstances, I recommend always checking for voltage FIRST before checking for continuity between any two points on a power circuit.

[Ike Zimbel]

I just purchased a 1928 house.  Before I turn on power, I want need to trace back every outlet and lighting fixture to its source in the panel(s).  In doing so, I will find any wyes that have been created over the years and determine which will need AFCI and GFGIs.

I will have to verify every wire in every run, checking all grounds, before I have ComEd turn the power back on. I will also make sure that any remaining knob/tube wiring is also disconnected.

What is a good tool I can use to inject from the receptacle end (preferably all 3 wires at a time), then go to the panel(s) and find/verify it/them? 

-Dennis

I was in the exact same situation some years ago, 1920's-ish house, fuse panel, knob & tube wiring and a newly renovated bathroom. My plan was to replace the fuse panel with a breaker panel, wire everything back up and then rewire the house on weekends, one circuit at a time. What actually happened is: When I took out the fuse panel, I looked at the existing wiring, and decided there was NO WAY I was going to re-energize any of it. Ended up taking a week off work and re-wiring the house. Found the usual horror stories, but the prize was that all of the new wiring in the bathroom was powered off the nearest knob & tube circuit! Tracing the wires is an admirable undertaking, but you might save yourself some time and heartache by just replacing it all.

[Dave Garoutte]

I was in the exact same situation some years ago, 1920's-ish house, fuse panel, knob & tube wiring and a newly renovated bathroom. My plan was to replace the fuse panel with a breaker panel, wire everything back up and then rewire the house on weekends, one circuit at a time. What actually happened is: When I took out the fuse panel, I looked at the existing wiring, and decided there was NO WAY I was going to re-energize any of it. Ended up taking a week off work and re-wiring the house. Found the usual horror stories, but the prize was that all of the new wiring in the bathroom was powered off the nearest knob & tube circuit! Tracing the wires is an admirable undertaking, but you might save yourself some time and heartache by just replacing it all.

That was my thought too.  80/20 rule.

[Dennis Wiggins]

I was in the exact same situation some years ago... Tracing the wires is an admirable undertaking, but you might save yourself some time and heartache by just replacing it all.

Last night I met with the contractor and we agreed that it will be way easier, and less cost all around (heating/plumbing/electrical), to just gut the house and start from scratch.

<edit> Also, the contractor said that ComEd may require a new service entrance (it is very old cloth covered cable) before they will power it back on.  Service amps TBD. That's my cue to put in a new panel now.

Thanks to All,
Dennis

[Tom Bourke]

Last night I met with the contractor and we agreed that it will be way easier, and less cost all around (heating/plumbing/electrical), to just gut the house and start from scratch.

<edit> Also, the contractor said that ComEd may require a new service entrance (it is very old cloth covered cable) before they will power it back on.  Service amps TBD. That's my cue to put in a new panel now.

Thanks to All,
Dennis

I bought a house of a similar age.  NONE of the existing wire was safe to use.  Even the "new stuff" had been put in so poorly it was damaged by wire staples and kinks.  Ended up living off my PA distro with band stringers running around the house till I could complete phase 1 of getting power in enough spots to live and run tools for further upgrades.

More recently bought a much newer house.  Found some really nasty handyman specials in the attic and electrical boxes.  Fortunately not so bad they could not be fixed by just doing a proper re-install of the lights and outlets as I replaced them.  I also had a new service put in because the old one was only 100A and I could not run my welder.


As for tracing wires and water pipes in such a house I have used an amp clamp and PSU with a lamp to limit current.  It involves running around the house with a long wire back to the source and creating a loop.  The nice thing about that test is you can notice if the current is split among several paths or if there are high resistance connections.


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