Diagnosing old wiring crimes...

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Diagnosing old wiring crimes...

Postby jharkin on Thu Oct 27, 2011 9:36 am

It always amazes me that with a 200 year old house the worst problems to fix are bad contractor work from the last 30 years or so.

ESPECIALLY fly by night electrical work. The house was just full of loose grounds, reversed outlets, bad splices, crossed circuits, hanging and open boxes. You name it, they tried it.

Anyway, Ive been working in the crawlspace fixing e latest problem. Our electric range takes forever to heat, and Ive found that the 30+ year old ungrounded aluminum SE cable is a mess -spliced twice to move it, in both cases using the metal box as the neutral path and taped up in other places. Anyway I cant say for sure that's causing a voltage drop and affecting a range but it sure is not helping. By code I think they should have updated it to a 4 wire when they moved it but oh well.

So I'm stringing a new 6/3-G line to rewire it. What a pain.


However, that is not the subject of this post ;) What is is what I found when I was down there. This is such a mess I had to draw it out.

First the circuit drawing, then I will try and explain...
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Re: Diagnosing old wiring crimes...

Postby eperot on Thu Oct 27, 2011 9:39 am

Looks like we had the same electrician!
Jacob Beaty House - c.1874
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Re: Diagnosing old wiring crimes...

Postby jharkin on Thu Oct 27, 2011 9:43 am

OK so what do we have here. This is my outdoor lighting circuit. Its one breaker that powers a post lamp on a single switch, and a pair of outdoor floods hung on the garage on a 3 way - one switch inside, the other in the garage.

The power goes first to a junction in the basement with the feed to the post then from there an ungrounded switching lead goes into that monster 6 way box in the crawlspace. that's where the fun starts. Note that this ungrounded 2 wire switch lead means that both neutral and ground STOP at the first junction. (problem #1) So where is the rest of the circuit getting fed?

I figured out that the 3 way run is taking hot off the post lamp switch. This makes sense since its a power->switch->switch->light run so the hot has to start there. But what about neutral? I found that they borrowed neutral from another circuit in that 4 gang box (problem #2).

And it gets better. Those boxes in the crawlspace wouldn't have ground except for an old dead line that also runs through (and is reversed, not to mention just twisted and taped). Problem #3

And even more fun. Problem #4 - After the second switch in the 3 way pair, there is still 14/3 running through the lights (why?) and after the second light there is a 14/2 run connecting it to another outlet string (huh?). This part I have not yet figured out since the junctions are up in the rafters of the garage. I have to go up there on the ladder this weekend to open it up.
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Re: Diagnosing old wiring crimes...

Postby jharkin on Thu Oct 27, 2011 9:54 am

So the plan of action.

First I need to go open up the light boxes in the garage and figure out why the last light in the string has a line to the garage outlet circuit. I'm guessing I might find that original the lights where wired for power there and only switched in the garage then they cut it when they added a 3way switch inside? (garage wiring is much older than inside) At least I hope that's all it is. If so I'll remove that line to avoid confusion.



Assuming that is the case here is the plan to correct things inside...

#1 - I'm going to rip out that old dead line all the way back to the main panel.

#2 - Replace the ungrounded run between the first and second boxes with a 14/3-G. This will let me bring proper ground and neutral into the 6 way (now 4 way) box. I'll use the red for the post light switch line.

#3 disconnect the shared neutral at the 4 gang switch box and cap the neutral on both ends of that first 3way wswitch leg

#4 Connect the neutral into the 3way switch circuit at that big box where it feeds out to the garage.


This should get the entire circuit on a common neutral and properly grounded. Only odd thing will be the 3way picking up hot and neutral in different locations. To be safe I think I will write a note on the inside of the box cover labeling this.

While I'm at it I need to attach a couple hanging boxes, ground the boxes properly, redo the taped splices with wire nuts, and black tape the hot white lead in that singe pole switch run.

Electrical Pros please speak up if you see any flaws in my logic............


Aren't old houses fun? :)
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Re: Diagnosing old wiring crimes...

Postby jharkin on Thu Oct 27, 2011 4:02 pm

Was on a half day today so I checked out the garage after work.

It gets worse.

The house circuit for those floods is interwoven with another light circuit in the garage. the neutrals are interconnected and the house circuit feeds the red hot from one end and the garage circuit feeds the black hot at the other end. What was this guy smoking?

This one is not too hard to fix. I'll just have to pull the garage circuit off the end, refeed it to that light in the middle, and take the house circuit out of the middle light and join it in a new junction box.

The other strange thing is that the garage light circuit also feeds half the outlets downstream of the switch. I'll tie those into the second outlet circuit in there, separating he outlets and lights.


----

So the bottom line is I have 3 different circuits, on 2 different breaker panels, sharing a neutral bonded in mutiple places. AND I have a 14/3 line in the garage with the 2 hots connected to circuits in 2 different panels.

WOW
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Re: Diagnosing old wiring crimes...

Postby Sombreuil_Mongrel on Thu Oct 27, 2011 5:02 pm

I don't see based on your diagram how the three-ways could function because there's no 3-wire running between the switches. Unless somehow it's in a loop from the panel side to the floodlight box. (not shown, but could be inferred because the wires continue on "somewhere" beyond the floods, as you noted.)
I'm no electrician. And this is why I am glad of it: wiring nightmare.
What I see is a good excuse to run new wiring.
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Re: Diagnosing old wiring crimes...

Postby eperot on Thu Oct 27, 2011 6:25 pm

I agree. I think this is a perfect opportunity to start sections from scratch and rewire properly. It would probably be easier than trying to get all the screw-ups working "right". That 6 way box or junction just sounds like a nightmare and fire hazard waiting to happen. I know we had an issue of still having the whole second floor power supplied by knob and tube, where it split off into some groups of romex. We had missing grounds everywhere...no surprise, because while you opened up a recepticle and saw romex including a ground in use, it turns out all they had done was attach about a two foot length of romex to the two wires of the K&T. Nice. Then, when we cut all the knob and tube lines up to the second floor out, the second floor was still powered! Turns out they had fed another old romex line on a separate circuit into the junction box where the knob and tube split off into romex. I feel your pain.

Old houses can be fun...old houses owned by idiots in previous lifetimes...not fun. :wink:
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Re: Diagnosing old wiring crimes...

Postby timallen on Thu Oct 27, 2011 7:01 pm

Yep, seems best to just pull it all out and start over.
multiple old houses: 1780, 1870, 1948, 1987 (all at the same time)
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Re: Diagnosing old wiring crimes...

Postby jharkin on Thu Oct 27, 2011 7:40 pm

There is a 3 conductor line connecting the 2 3 way switches. I was just being lazy with the drawing - I couldn't find a 4th pen color so I didn't draw the grounds.

Maybe I'm making this sound worse than it is? Other than the stretch of ungrounded wire its all modern NM-B cable. I just have to reroute a couple of connections, redo the bad splices properly and rip out the unused pieces. Rewiring this entire circuit from scratch would meant tearing open walls and digging up the yard, not really necessary I think.
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Re: Diagnosing old wiring crimes...

Postby timallen on Thu Oct 27, 2011 11:05 pm

jharkin wrote:Rewiring this entire circuit from scratch would meant tearing open walls and digging up the yard, not really necessary I think.


If you've got appropriate cable already run between points A, B, C, and D, and you're happy with where those points A, B, D, and D are located, then no, there is no point in pulling it out just to put it back in again. BUT, you may want to undo ALL of the connections, and then work your way through the circuit, re-doing the necessary connections (from scratch, as it were), in order to make sure that all is making sense (and pulling out anything that is extraneous).

Another approach would be to do it on paper first. Start with a blank sheet of paper, and draw the circuit out the way you think it should be, from start to finish, from scratch. Forget about what currently exists. Only once you've drawn out the "new" circuit, only then do you compare the "as built" to your new plan -- at which point you can then identify which components of the plan are already in place (i.e., what can be recycled from the existing installation), what needs to come out, and what else needs to go in.

I guess what I'm saying is that it's not necessarily the actual wiring that needs to be pulled out and done over from scratch, but the thinking. Believe me, I know it can be [s]frustrating[/s] a challenging puzzle trying to figure out what the persons who came before you were thinking, but sometimes I'm just not sure it is worth the effort when what you're going to need to do anyway is to just start over from the beginning. And maybe you've already done the re-thinking -- but the diagrams presented so far have been of the old and not the new. Anyway, I hope this helps. Good Luck!
multiple old houses: 1780, 1870, 1948, 1987 (all at the same time)
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