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#169862 - 10/18/07 10:40 AM Evolution of materials and wiring methods
ChicoC10 Offline
Member

Registered: 05/30/07
Posts: 169
Loc: CA
Does anyone know of good sources of information that cover the changes in materials and wiring methods used over the years?
While I'm interested in how and why it used to be done in the old days all over the country and world for that matter, I especially would like to know what they had to work with and what rules they were bound by in my own neck of the woods over the last 100 years or so.
In Chico, CA, as I find myself prowling around 75-100 year old houses looking at K&T, cloth and paperwound cable, early plastic insulated cloth covered cable, and several different eras of plastic sheathed NM all grafted together, I wonder what the trade was like when the house was first wired and what it was like during each subsequent remodel.

Of course I then tell the owner I won't add the 800W worth of cans they want unless I first get rid of some of the old stuff and then pull a new circuit or two from a reasonably modern panel.

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#169870 - 10/18/07 03:10 PM Re: Evolution of materials and wiring methods [Re: ChicoC10]
Sixer Offline
Member

Registered: 08/08/05
Posts: 264
Loc: Canada
A quick search on google found this site which may be helpful:
http://www.codecheck.com/wiring_history.htm

My grandfather was an electrician and did many new homes back in the 30's. The K&T wiring was done with a brace and bit. In the floor joists the holes were drilled at an angle upwards, and the "tube" was put in from the top - that way it couldn't slip out. All joints were soldered. We always see scorch marks on the joists where K&T joints were soldered.

I have the original blueprints for my 1938 home. Back then there were only two receptacles in the house: one in the kitchen for an electric iron, the other in the living room for the radio. All rooms had ceiling lights. The service size was 30 amp 120/240 with 4 circuits (fuses) in all. Other than lights and a couple of receptacles, electricity wasn't needed much. The range was coal and wood with a water jacket on the side for hot water. Heating was with a coal furnace. The "fridge" was an icebox.

Quite primitave compared to today's standards.
_________________________
Sixer

"Will it be cheaper if I drill the holes for you?"

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#169873 - 10/18/07 04:41 PM Re: Evolution of materials and wiring methods [Re: Sixer]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I worked on a volunteer project back in Md that was bringing some WWII vintage government housing up to the 75 NEC (A "Habitat" sort of thing). They had one receptacle in each room and an overhead light. There was only one receptacle serving the countertop. These had oil heat, hot water and a propane range. It was also 30a/240v with 4 fuses.
We took it up to 100a, put in the required receptacles and electric hot water. This gave them the breathing room for AC so we put in a couple dedicated circuits for window shakers. The heat stayed oil and the range was still propane.
_________________________
Greg Fretwell

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#169874 - 10/18/07 05:19 PM Re: Evolution of materials and wiring methods [Re: gfretwell]
NORCAL Offline
Member

Registered: 09/25/02
Posts: 805
Since you are in the "People's Republic of Chico" you must really love to work in Drake homes.:(

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#169891 - 10/18/07 09:20 PM Re: Evolution of materials and wiring methods [Re: NORCAL]
ChicoC10 Offline
Member

Registered: 05/30/07
Posts: 169
Loc: CA
"People's Republic of Chico" LOL
Yeah, all the "highly educated and morally superior" students with no lasting economic ties to the area and their mentors keep it that way regardless of how I or my friends and family vote. Of course, the state as a whole isn't any better.

I wired a hundred or more Drake Homes before going on my own, 98-04. One a day was all the boss asked of us but his standard was still high.
Nothing wrong with any of those outside of being low to middle tract houses.
I've been told it wasn't always that way.

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#169895 - 10/19/07 05:13 AM Re: Evolution of materials and wiring methods [Re: ChicoC10]
Texas_Ranger Online   content
Member

Registered: 12/17/01
Posts: 2331
Loc: Vienna, Austria
I'll try to give a short overview over Austrian and German wiring methods.
The oldest style of wiring were individual rubber insulated, cloth covered conductors nailed to the wall surfaces with porcelaine insulators. Where these wires came down to switches or receptacles they were put in conduit, at least in later installs of that kind.
As far as I have seen this wiring method was used until the early 1900s, both indoors and outdoors. A second, more elaborate way of wiring was to use twisted lamp cord on smaller knobs, a wiring method that was outlawed in Germany in 1910 but continued in Austria well into the 1920s (I know an install in a city that did not get electricity until 1924). Both of those styles are very rare but still found in old houses.
In both cases stranded wire was used, junctions were either done in porcelaine boxes with fixed set screw terminals (more typical for Germany) or flying, with conductors wrapped around a screw, tightened with a nut and wrapped in bituminated cloth tape.

Upscale homes around 1900 started using concealed wiring. Solid wire, rubber insulated, cloth covered and bituminated. Either directly plastered into brick or stone walls, directly placed into plaster and lath ceilings or installled in conduit.
Conduit back then consisted basically of bituminated pressed cardboard, the better version had a very thin steel cladding (with a seam running along). The latter version could be bent with tools similar to wiremold tools.
Switch boxes were made of steel with an inside covering of bituminated cardboard since most systems were ungrounded and electricians tried to isolate every metal surface. However, flush mount switches did not come up until the end of WWI, older houses had flush mount wiring but surface mount switches screwed to wooden nailers plastered flush into the wall.
Junctions were done by the means of wood frames, made of wood strips 3/8" by 3/4", open sides and back, handmade steel covers. Splices were made with screws like the surface wiring. This kind of frames was used (for LV wiring) well into the 1970s!
Probably in the 1920 an alternate wiring method for retrofits was introduced, so-called pipe wire. Basically this was a cable with a rigid brass, steel or aluminum jacket and a sisal filler. Bending worked with the same tools as "Bergmann conduit" mentioned earlier. A sturdier version featured a rubber filler and two coatings of bituminated cotton woven around the jacket to be installed in moist/wet locations. The latter version can still be seen in many basements. A variation of this cable with a PVC jacket seems to be manufactured until today!
In the 1950s PVC insulated wires and (in the late 1950s) PVC boxes and conduit started to appear.

At the same time two new kinds of cable evolved, modern round nonmetallic cable with rubber filler (NYM, Austrian YM) and flat multiconductor cable (very thin jacket around each conductor only loosely held together like zip cord, German designation NYIF, Austrian YM-STEG). The latter is pretty much extinct, mostly due to the fact the German version had a cheap rubber jacket that failed quickly instead of PVC and the Austrians aren't to keen of cable and prefer to use flexible PVC conduit instead.

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#169914 - 10/19/07 06:40 PM Re: Evolution of materials and wiring methods [Re: ChicoC10]
e57 Offline
Member

Registered: 05/27/03
Posts: 2837
Loc: S.F.,CA USA
 Originally Posted By: ChicoC10
"People's Republic of Chico" LOL
Yeah, all the "highly educated and morally superior" students with no lasting economic ties to the area and their mentors keep it that way regardless of how I or my friends and family vote. Of course, the state as a whole isn't any better.


Much the same in most any college town where transitory students out number actual residents, and make a point of impossing their new found, ill-concieved notions upon the populous with their new voter registration cards. Whats worse is when they all move back later in life out of some sort of nostalgia seeking mission and gentrify you right out of your way of life. The Greater Boston Area - where I grew up has roughly 40 colleges and univerities. Around the mid-80's all of those former students moved back and quadrupled home prices in certain areas. I arrived in San Francisco just in time for the Dot-Com boom and later bust...

Anyway, most of the code issues for K&T have not really changed much since the 30's. And if you browse throught that section much of the actual code will match what you should see in the building you work in. A while back I wrote a little paper about it. (Because I had to show entirely too many people what to do with it.) I also got some help with this from some of the guys here too...

http://www.markhellerelectric.com/wusplice.pdf

Around here you won't see torch marks on any K&T done prior to 1950, as solder was usually poured over the fluxed joint (Splice) with a laddle. Often this was done from above in the joists without the sub-floor in many of the Ed's and Vic's of this area. (Saw some pictures of some being build a while ago...)

FYI - SF was still allowing K&T as original wiring clear until the 70's! And around the mid-60's allowed 3-wire K&T to be installed with thermoplastic wire (TW). Other than that most of the K&T work I do is in homes that were either built before electricity and converted, or when it was considered a fad... i.e. having both GAS, and electric light... Sometimes I go in and find out the gas is still on, just capped with a wooden cork, and a 1/2 fixture hickey... Although most had the gas lines cut off after the Great Quake of 1906, and subsequent fire. I have also worked in a few homes that either out of nostagia or neglect still have operational gas lighting... Imagine the suprise - you get called in to remove a fixture from an older home as the owners are moving, ("Architectual theft" - these people took all the stained glass too...) and find that in order to remove this 150 year old chandelier also requires a plumber to take it down. I knocked a valve on the fixture and it started hissing at me.... For S&G - I lit it - just to scare the death out of the customer. Oh happy times... "Hey check this out." as I flicked my Bic.
_________________________
Mark Heller
"Well - I oughta....." -Jackie Gleason

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#169922 - 10/20/07 07:12 AM Re: Evolution of materials and wiring methods [Re: e57]
ChicoC10 Offline
Member

Registered: 05/30/07
Posts: 169
Loc: CA
Thanks for the input. Your insight (and opinions) are appreciated.
I found this http://www.amazon.com/Old-Electrical-Wiring-Maintenance-Retrofit/dp/0070578796
and though it's a bit spendy I think I'll buy a copy.
I haven't made it to Europe yet but when I do I'll keep my eyes open.
Great paper Mark!

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