Been running into a lot of old wiring lately and thinking it'd be interesting to know how old a lot of this stuff is.

Wondering if anyone knows the time periods for when a lot of this stuff was used:

• Knob & Tube: 1890-1930?
• Whatever that stuff is that was pulled through abandon gas-lamp piping: ?
• BX w/ cambric insulated conductors/no EGC: X-1940?
• NM w/ fabric sheath and cambric insulated conductors/no EGC: ?
• NM w/ fabric sheath and plastic/thermoplastic insulated conductors/undersized EGC: ?
• Aluminum NM: 1965-1975?

Just guessing on the dates. Anyone know any answers or have any other wiring types?

-John

Interesting topic, BigJohn.

My only addition would be...the earliest use of varnished cambric with flexible metal wrap I've seen is close to 1900 at the Dole Mansion in Crystal Lake, IL. He used European craftsman and probably had access to materials not generally available. I'm working on another home in the same neighborhood (and approx.time period) which has varnished cambric in conduit.

Dave

K&T was used in homes right up to the early '60's. when the acceptance of ground wires sounded the death knell to this method.

Romex first came out during the Depression, with paper around each insulated wire, and a cloth jacket over the whole.
In the '60's, it was allowed to have a ground wire that was smaller than the conductors. Romex from this era will have a #16 ground wire.

My home was built in 1939 and wired with knob & tube - minimal wiring I might add. One overhead light in each room on main floor, one light on top floor, one receptacle in kitchen (for iron), one in living room (for radio).....all fed from a 30 amp 4 circuit panel. Wow, have things changed since then!

The house I live in my father built in 1957/8. It has romex with ground wires(#16 I think). Also has breaker panel original to house with separate 100 amp fused disconnect.

House is in Ontario Canada.

Hey Dave, where is the Dole mansion? I left Crystal Lake when I was 13. I remember a Dole Avenue, where I used to mow lawns, just a block or 2 off Rt. 14 I think. Haven't been back there in almost 30 years.

Big John, there's a good book called "Old Electrical Wiring" by David Shapiro. It has a section of history and dating. Most of the K & T I have seen was from the 1800's till the early 30's, then it seems BX became the choice. Aluminum wire has been around since the 40's,but wasn't used widely till the 60's & 70's, mostly from 1965 to 1973, or the Vietnam years.

The reduced size neutral wire was available in the early 50s. The house my parents built in 1955 had it. I understand this was necessary to pass "GI Bill" inspection but that may not have actually happened outside the DC area.

Check your email BigB. Sorry I called you John(confusion with BigJohn). Check out Lakeside Legacy, which states the Dole Mansion was built in 1865, not 1900. Is it possible flexible varnished cambric was around in 1865??? It's a three story with basement & didn't appear that the wiring was added after original construction.

Dave

Dang, Daves working at the Dole Mansion. Last I knew it was a day care for children, somewhere to serve court ordered comunity service, and a half way house for drug addits. Not the best combination IMO.

What's varnished cambric look like?

Tom

My home built in 1952 in NYC uses the cloth BX with no bonding wire. It's all being ripped out now, replaced with minimum #12 BX even though NYC code now allows Romex. Surprisingly though, the house had 100A service (Murray) with breakers, only 12 of them, which needless to say got a lot of trip use.

There are 4" boxes (also now gone) above every ceiling fixture serving as J-Boxes for receptacles, other lighing fixtures... everything, a real mess. The insulation in the boxes are so bad you can strip it all off with nothing more than your fingers! The insides of these boxes show signs of excess heat, and perhaps even arcing. There were FEW home runs that my Fluke meggar DIDN'T find bad.

I can't imagine other homes in the area being any better. Surprised there aren't fires. Whats worse, is many folks are adding on second stories without ripping out the old stuff, covering over J-boxes previously accessible in the former attics. Hate to be the one to have to troubleshoot the inevitable problems this old wiring will pose in the future. Wonder how this stuff passes? And it always seems to.

I thought I got the shock of my life (no pun intended) when I saw a few runs with those evil silver colored conductors. I said to myself no way, aluminum wasn't used in branch wiring in the 1950's. Apparently, it was some kind of aluminum or silver "coated" copper, as the center of the conductor was indeed solid copper. Not that it makes any difference now with most all of it ripped out, but has anyone ever seen that kind of BX with the silver/aluminum coated conductors?

Something tells me in 20 or 30 years (perhaps less) a lot of sparkys will be laughing about all the miles of CAT5 wiring houses now have today.

Joe

HEY Joe!
I have seen that BX to which you are reffering to... Many times!
If I remember correct my X G/F's apartment building was full of it... It was a steel armour cable with cloth covered rubber with a tin plated copper conductor and it might of had a bonding "strip" inside.. I guess at that time it wasnt bad BUT I noticed it started to break down, the rubber is literally drying out, cracking and falling off so changing out fixtures or devices gets really tricky... I guess the building to have been built in the mid to late 50's or early 60's because I also found Romex in some of the walls that contained grounds BUT there were ungrounded 2-pronger outlets installed, as well as all sorts of odditiesthroughout the building from that time period.

A.D

Cambric is cloth Tom. It's usually in decent shape in outlets, but it deteriorates with heat. Also the light is the major juncion box in the room and usually a small pan box. Sometimes you pull on the wires & all the insulation flakes off so you're left with a batch of bare wires.

The Dole Mansion with addition was the property of First Congregational Church of Crystal Lake for the past 20 or so years. Friendship House was the day care center...our children went there and we're members of FCC. The day care, church offices, banquet hall and third floor rooms were all in the large addition.

No halfway house. I don't know about community service, but the daycare had security entrance & fencing. The mansion itself was not occupied. I did some wiring in the day care center, but not the mansion. It would be a black hole for time.

It was recently sold to Lakeside Legacy and major repairs have been made with donated money, with a huge amount donated by Sage, a local company. It has a new roof with copper gutters and interesting carpentry details.

Dave

If I'm not mistaken, the old copper was nickel plated.

I have a quick and easy method for dealing with old, flaky insulation:

Strip a few inches of NM conductor, and push the empty insulation onto the old wire, as far as it will go, then re-strip. If the fit is tight, use insulation one gauge up.

Usually, the splices themselves will keep the sleeves in place, even up inside the sheath/armor. If need be, secure them with a wrap of tape at either the emerging end or the stripped end.