Replace cloth-wrapped wiring in conduit?
 

I've replaced the outdoor electrical service for my house.

My next electrical task -may be- to replace the old waxy-cloth covered wiring inside the house.

All the wiring inside the house is (i'm guessing) a mid-20th century upgrade. All conduit, all the time. Inside the conduit are said waxy-cloth wires.

So . . . . What say you? Do I need to replace this wiring if it's not 'broken?"

If so, can I just remove it and shove some romex through the conduit? (if it will fit)

I like the conduit, actually. The walls are plaster and lathe, so just shoving new wiring through the conduit is a quick and easy idea, if that's acceptable.

thanks

Why not pull single wires through the conduit? Smaller diameter, less friction.

OH sh it. Excuse me. Whatever you do, you have to replace that stuff.

Yes replace, but pull three singles through, no Romex. The first curve you get to you wil HATE pulling the Romex!

Cheaper too!

Your best bet to pull will be to make a hook in the end of the existing and tie a loop in some string. Then tape the loop closed with a little taper up the wire to make it easy. Pull the string through, then pull the string through with the new wire done the same way.


I'll let someone more experienced recommend the wire, we tend to run everything in 10 or 12ga THHN stranded since that's what we have to use to run up sign poles.

This man speaks the truth.

Absolutely not Romex through conduits.

Use fish tape, hook wire to it and pull through. Having Conduits are much better then Romex. Why do you think you need to replace the cloth wiring? If you have conduit, then it isn't knob and tube (1920s). your existing wires inside the conduit should not heve cloth sheathing on it. Take a pic of it for us will ya? Maybe its that way in Colorado back then. My building restoration experience is limited to so cal.

This is the 'correct' method. 14 ag THHN/THWN would be sufficient for 15A circuits although 12 ga would give you extra amperage. Pull 3 wires - black/white/green representing hot/neutral/ground. The conduit is often used as a ground but that relies on metal to metal contacts which may or may not be there hidden in the wall. The old thick cloth/paper insulation was wrapped around a rubber core of insulation on the wire so it is safe as long as it is terminated properly.

Ian

No romex through conduit! Also conduit is not legal to use as a ground conductor. You have to run a separate ground.

Is this what you have?

http://forums.pelicanparts.com/uploa...1385217687.jpg

If the wires are not damaged then they do not need to be replaced, they should be solid copper.

In our home the only wires that I have trouble with are ones in the ceilings. The heat from the lights breaks down the rubber insulation. I would concentrate more on running new circuits to places that you need more power, like bathrooms and kitchens.

Pulling wires through bx can be done but 3/12awg wires is a tight fit, and all bx ends need bushings in them.

This is all based on you having bx. If you have normal conduit it's a lot easier.

This is my favorite part of your question.

Quick and easy, as a part of home remodeling, is a surprise event - not a planned one. I've been rehabbing on and off for 25 years. I can count the quick and easy projects on my fingers. They usually cost twice as much and take 4 times as long.

Of course I am figuring in the many trips to the hardware store. Its tough to get everything in one trip. Every trip to HD usually starts with a stop at the return counter because you always buy more than you need in an attempt to eliminate another visit. Seldom works for me.

Thanks, Dudes! Single wires it is!

Nope, it's not the that it's the other stuff.

http://forums.pelicanparts.com/uploa...1385219300.jpg

This house had knob and tube and got 'updated' to the nice, big, non-flexible conduit sometime.

The wiring seems 'fine', except like Peppy here and there in overhead boxes where the heat has broken down the cloth.


The conduit serves as the ground right now.
Do I leave it or should I pull a green wire because I'm in there?

Thanks! SmileWavy

Pull 3 wires, 12g preferred. If the existing wire is copper, you might just want to leave it. If it's aluminum, it definitely needs replacing. Just put a grounding rod near the panel for your ground.

If it that BX armored cable like peppy showed there is no way you are going to get just the wires out of there. I would guess that wiring dates to the 30's or 40's.

If the rubber is not deteriorated why not just leave it and make sure you have the right ground fittings on the jacket?

So true. I now pick my rehabs/flips that are relatively close to a HD or Lowes. Each project takes at least 2-3 trips.

I hear you, I think I meant "quick and easy" compared to having to bust open some walls to get a look at stuff. I'm approaching the end of my rope with plaster and lathe, so fishing some wire actually sounds. . . easy and . . . not dusty. :)

It's copper. When I had my outside service done he did proper ground rods etc. so I'm getting closer to being correct.

We had the same issue in our 60 year-old house last year. A couple light switches started shorting out, prompting our "update." We had a handyman/electrician replace our wiring via the above sting-and-new wire technique. The insulation was intact, except for the ends (where connected to electrical switches) as that's where heat had broken down the insulating cloth over the years. The existing conduit made the job much easier (only 1 hole had to be made/patched).

And if you have room, go with the thicker gauge wiring. Its nice to have more capacity in the wiring than you have to have. Running a space heater at the end of a run can over task some smaller stranded wiring, so good to go up one size...

No doubt about it, it will be a big job. You would have to map the wiring to locate the hidden junction boxes that may be lurking in the basement & attic or in closets etc. Buy 4 rolls of wire (add red for the 2nd hot lines as shown in the junction box you posted) & buy or make a cradle to feed them smoothly. A local electrical distributor would be a good source for supplies.

Ian

Can I crimp the new wires to the old and use the old as my 'fish' line?

thanks everybody.

That's the best way. Make sure you have plenty of "lube" on hand.

I don't see why not. Try it and see what happens? Someone with more experience would be better to listen to, though. When my electrician did it, he removed the old wiring, and then snaked a semi-firm line (with a hook on the end) from one end to the other, and pulled the new wire through the conduit. Seemed like more work to me, but he must have had a reason why he did it that way, I reasoned at the time.

You can do it that way if it's a relatively straight run. Sometimes it's easier though to pull the string and then the wire so you aren't pulling the weight and resistance of the new wire with the brittle old wire.

Another trick, you don't need I buy a wire caddy if you have a step ladder. Just find a rod that will go through the spools of wire, lay one end of the rod on a step, the other on one of the support braces in the back. Not elegant and it will slide around, but it will let your wire spool easy and it's free or nearly free.

Yes lube is your friend. When I did it, I had my wife wearing rubber gloves and lube in hand putting it on everything.

Lube is your friend... But that is some nasty crap!

You can not use it as the neutral return but you can use it as the safety ground up to a certain amperage circuit.

I think I just found my new sig line.

If you decide to pulling wires, get a ground wire through at the same time. Those old rigid conduit for residential use are usually small, so pulling wires are going to be a PITA. Hook both ends of the wire and have someone push from the other end, and yes, use lube. What year is the house built?

The biggest concern is the knob and tube wires mixed in with the conduit. That has to be address if they are mixed and matched. I have seem many blotched jobs where they connect knob and tube wires and run them into a light box tie to more modern wires or the other around. Make sure before you start pulling.

The House is 1928.

What do you mean when you say "Knob and tube"? I'm thinking I dont' have any of that any more. there are some remains of the old ceramic-post stuff in the attic but it's unused.

I think I could get 3 14AWG wires in these conduits pretty easy. I think it's 1/2".

thanks

I also live in a 1928 house. The original wiring here are canvas/tar type insulated wires in solid, thick wall steel conduits with some break-out boxes. The biggest problem I encountered was when I wanted to replace various switches or light fixtures. Often the insulation crumbled off to bare wires caused by insulation age and frequent bending in the outlet boxes, especially right where the wires entered the boxes from the conduits. I was able to repair the insulation by slipping 1/4" heat shrink tubing over the wire ends reaching as far into the conduit as possible. That cured the crumbling insulation problem and created a durable new insulation inside the the boxes. I found that undisturbed canvas/tar insulation inside the conduits seems to be quite stable and durable and does not necessarily have to be replaced.

And as far as what size wiring you need inside the conduits: That depends on how that wiring is fused. 14 AWG is good for 15 Amps but for 20 Amps you would need AWG 12. That is also how the wiring was originally done in my 1928 house.

All that with a word of caution. I am not a professional house electrician. I have experience in general electronics and try to use common sense and what I know about house wiring code.

Keep in mind the breaker should always be the weakest link! Up to and including the outlet.
There are also 15amp and 20amp outlets.

Funny story:
The other day she smelled something wrong.
I didn't.
Then I did.
Then I didn't.
It smelled like burnt rubber, which is classic wire insulation overheating.
Oh ****.
Smell occured in different rooms, at different times.
I sniffed the electric space heater and outlet. Nope.
I sniffed the crap light fixture. Nope. But some of the bulbs were hot (even cf) and changed.
Then the smell came back strong again.
Sniffed the cat's head.
Skunk.

Thanks; there is some of that up in the attic but it's all dead at this point.

Jeremy, If you aren't sure about something electrical related, please have a pro look at it. I've been doing it for 30 yrs. (Although heavy commercial mostly..) The one thing I really don't like doing is giving advice sight unseen.

And as a firefighter I've seen the result of mistakes and bad advice.

Really good advice.

I spent 7 years in the electrical supply biz early in my career & household wiring is just low voltage stuff. :D My son-in-law spends his days turning dams & factories on & off.

That said, I really like porwolf's heat shrink solution.

Ian

No more knob and tube is great news. Heat shrinking is not to code, at least not around here. Temp. fix is ok until you go in there and "get it all out". Vinman is correct, it hard to tell just by a few pics. It might be too much to get you to take a pic of it from the other side of the ceiling? My advice is to pull all of that stuff out and start fresh but using the same conduits will be fine. You can get 3 12awg wires in there with ease. Hopefully you don't have too many bends. Are you doing this yourself?

Thank you. I'm actually pretty . . . acutely aware about the basics, I was just concerned about

A. Do I need to mess with it at all?
B. If so, what's the best way?

I definitely understand all the concerns and I just want to assure you I'm not running around in my attic fooling around with electrimical wires.


I want to get some insulation blown in to the attic and right now is a great time to get a road map of these conduits and sort it out before I have to swim through 2 feet of fluff.

SmileWavy

Good. Safety first. I will admit that I have done some pretty stupid electrical tricks in the past. I blew a hole in a good pair of wirecutters cutting a wire in my basement on a ladder one time . . . And I agree that the heat shrink is only a band-aid but it could be useful as such.

Ian

One of my local electrical distributors just mentioned some new "dry" lube. It is sprayed on wet with a "Windex" type sprayer. It dries pretty quickly leaving a dry lube on the wires.