Wiring Fox paw

GW

Plumber couldn't go under the wiring I guess

Fred

That old tube and knob is dangerous stuff! Next priority should be to replace that stuff.

GW

Yea it's quite scary

EBEBRATT-Ed

Wouldn't have been as scary if the plumber had a brain. There's still tons of that in use, in walls etc. It's fine unless the old RHW rubber covering has been overheated, or exposed to high ambient or some knucklehead pulls it down from it's running board

GW

What's really odd is the porcelain tubes make it seem like the old galvanized pipe may have been there first.

EBEBRATT-Ed

Noticed that, does look a little strange. Looks like a pc of that running board was cut out.

Time for some Romex

BobC

Knob and tube wiring that was properly installed is very safe as long as nobody tries to modify or add to it. You cannot unsulate over it either.

Bob

ChrisJ

I agree with Bob, K&T is fine and certainly isn't "dangerous stuff" when it's treated correctly.

Our neighbor against my advice put 30A fuses on a circuit I had 15A fuses on for them and then blew the 30s! I've been meaning to setup an experiment using 14-2 romex and a 30A fuse to see what it'll do. After her husband,a good friend of mine died, I put all 15's back and that's as it sits now.

I suspect unmodified K&T is more robust for it's size than romex, not to mention it cools better.

K&T's biggest problem is hacks and people putting the wrong fuses in. I don't see people swapping in bigger breakers, why they think it's ok with fuses I'll never understand.

BobC

i was up in York Maine a few decades ago staying in a nice old B&B. On our last day the owner was having a yard sale and i spied an old Lafayette stereo receiver. He wanted $25 for it and I asked what was wrong with it, he said one channel was fine but the other wouldn't work. Upon further questioning he said the local TV repair guy looked at it but couldn't get parts.

I offered him $10 and walked off with it. When I put it on my bench I found a driver transistor had been installed backwards, I turned it around set the bias and it worked like a charm. It looked like someone had replaced an output transistor and it's driver but made a small mistake. I used that old receiver and a pair of small RS Minimus speakers in the kitchen for 25 years and it never gave me a problem until . . .

One day I came down from taking a shower and was getting ready to head for work, I was on the second shift and had to be at work by 2:30 PM. As I was putting a few tings in my computer bag I noticed a burning smell, I looked everywhere but couln't find anything wrong. I called the local fire department and asked them to come look. They came down and went over things and couldn't find anything. The quizzed me about the symptoms and I told them the smell was only in the kitchen and that all the appliance cords were cool and everything appeared to be working.

One of them got a thermal camera and began to scan things, when he got to that old receiver he stopped asked what that was. I put my hand on it and it was VERY hot. I picked it up and could tell the smell was coming from it. I put it out on the back walk and thanked the guys for the help. They dropped me off at the train station and hot footed it to work - an hour late.

The next day I put the receiver on the bench and found someone had wrapped the ac fuse on the unit with tin foil and rendered it useless. Further examination showed a capacitor had failed and the overload cooked the power transformer, a fuse would have blown but that couldn't happen because of the foil.

As designed that receiver was safe until someone used tin foil instead of the proper size fuse. The lesson I learned that day is always check that fuses are the correct type, don't assume they are ok just because something works.

Bob

Gsmith

Interesting thing is that in our area of northern NJ with loads of houses built before 1935 or so with knob and tube, homeowners insurers refuse to insure houses with k&t when houses are sold unless they are retired and all k&t removed. What a shame.

Jamie Hall

Gary Smith said:

Interesting thing is that in our area of northern NJ with loads of houses built before 1935 or so with knob and tube, homeowners insurers refuse to insure houses with k&t when houses are sold unless they are retired and all k&t removed. What a shame.

It's not just northern NJ. The main place I care for had all the K&T taken out in 1955 and replaced with BX, beautifully done according to the code then in use. The fuse boxes were left as fuse boxes (there are five of them. Don't ask). I have had the dickens of a time finding a company which would insure the main building because of the fuses, though I finally did.

I totally agree on the wrong size fuse problem, though -- for which reason all those fuse boxes are built so that they will accept only the correct rating fuse, or smaller. Still doesn't eliminate the penny jammed under the fuse problem, though -- and I've seen that, too (but not on my watch!).

MilanD

Looking at the wires, looks like house was built long before electricity was added. My 1911 home has k&t that was ran through the joists. These seem ran on the surface. Turn of the century and pre 1911 vintage. The plumber should have lifted those tubes into the jois space above the k&t, or at least had the wires replaced and installed a few junction boxes over the water lines.

ChrisJ

> @MilanD said:
> Looking at the wires, looks like house was built long before electricity was added. My 1911 home has k&t that was ran through the joists. These seem ran on the surface. Turn of the century and pre 1911 vintage. The plumber should have lifted those tubes into the jois space above the k&t, or at least had the wires replaced and installed a few junction boxes over the water lines.

99% of mine is gone but from what I found the k&t was run on the surface as well using porcelain insulators nailed into them. All of it was ripped out in 1987 due to a cigarette fire in the livingroom.

Fred

I feel Knob and tube and old fuse boxes aren't safe because of the age of the insulation, there fact that anything 100 or so years old has been tampered with by some DIY'er or an electrician who took the easy way out, on a repair and the simple fact that that insulation was good in its day but it has deteriorated over the past century. Additionally, there is no ground on anything, except maybe the fuse box itself. In our areas, as has been said, most insurance companies won't insure a building with tube and knob and a couple nearby municipalities won't even allow a house to be sold until after an inspection and tube and knob removed/replaced. I'm not sure what else anyone needs before they consider it dangerous. It is a fire hazard by almost anyone's standard.

Gsmith

I would love to see some statistics on the actual numbers of house fires started by k&t wiring. I don't hear of it happening often on the news, but maybe the insurance actuaries do have the stats and maybe it really is a problem.

Steamhead

I'd bet more fires resulted from Federal Pacific circuit breakers than knob-and-tube wiring.

http://inspectapedia.com/fpe/FPE_Stab_Lok_Hazards.php

KC_Jones

If K&T is done correctly the insulation on the actual wire is redundant. The ceramic knobs keep the wire away from any from any framing. The tubes are ceramic and used to pass through any joists. In all honesty it would work just fine with zero insulation on the wire. The only place it matter is when it's being hooked to a fixture and in those instances there was an extra heavy insulation sleeve added to the wire. I do agree the lack of a ground isn't ideal by any means.

It isn't unsafe by design, what is unsafe is when people mess with it. That is the primary reason insurance companies and others want it ripped out, you just don't know what some idiot might have done. I think we should be clear on the problem and not blame the dead men's systems, but blame the stupid live men.

I ripped all of mine out when I moved in because some moron before me had messed with it so much and did a less than poor job with it.

My $0.02.

ChrisJ

Lack of a ground is easily solved by adding GFCI receptacles. No you do not need a ground for them and it's acceptable by code.

EBEBRATT-Ed

Yeah, the inspectors for the buyer want it all gone. When people say K &T is NG I always say if it was NG it would have been replace 50 years ago. Most of that stuff is at least 80 years old by now.

The enemy of any wire is heat especially the old RH or RW rubber covered wire which is why it shouldn't be buried in insulation or overloaded.

Of course it has no ground conductor too.

as far as pennies in the fuse box that's why they came out with the "fusestat" adapters so you couldn't put an oversized fuse in.

Funny thing that the home inspectors want the fuses gone just so they can't be tampered with. I will take fuses over breakers for safety any day. Breakers can fail to trip, fuses never can fail

Just think. Back when that stuff was installed most rooms had 1 light (often a pull chain at that), 1 receptacle,

no dishwashers, no disposals, cooking was probably gas or kero, or wood ,maybe a refrigerator (although they were also gas fired), maybe a wringer washer, no dryer the boiler or furnace was probably coal. The only appliance was probably a toaster.

30Amp 120 volt electric service in the house was common.

Most houses had maybe (4) 120 volt circuits

But it is time for that stuff to go away

And yes @ChrisJ you can use GFCI without an equipment ground on knob & tube or to replace a two wire receptacle that has no grounding means. I believe they are supposed to be marked "no equipment ground"

Jamie Hall

A few miscellaneous comments. First -- totally agree with @EBEBRATT-Ed -- I'll take fuses over breakers any day. As I mentioned previously, if the fuse boxes are set up to take the fusestat type of fuse, there is no way you can put in a fuse which is too big for the circuit protected. Second, back in the day it was legitimate to use the armor on BX as a ground, so if circuits are wired with BX a ground is available, although it doesn't meet the modern codes. On a rewiring job or repair, however, it's a good idea to check the continuity of that ground -- someone may just have managed to break it. It's true that the F&T didn't have a ground, and there are an amazing number of much later jobs which used Romex which don't have a ground -- nor any way to get one. The comment on RH and RW insulation is one to watch for -- not so much in the wiring itself, but in junction boxes and fixtures, where it may well have deteriorated.

On the subject of grounds -- there are also an amazing number of boxes where the grounds were either not properly installed or not connected -- and that applies with equal force to circuit breaker boxes. The only reliable way to tell is to open the box and inspect and verify the wiring.

Any electrical work around the places I care for is done with BX armored in dry locations and UFB for wet or damp locations -- but where I use UFB (for instance barns!) it is either buried or run on the surface. Little furry critters sometimes chew on the cable if it is hidden, and unless you have arc fault protection breakers that is asking for trouble!

Fred

I guess it's a matter of opinion and the quality of the installation and modifications over the years, as well as the condition of the wiring itself. I just remember having it in the home I owned before the one I'm now in. The insulation was cracked and even broken off in small areas. Touch some of it and you did the happy dance for a minute. I ripped it all out and replaced it and the two old fuse boxes. If you have it in your home and you are OK with it and your insurance company is OK with it, I too am OK with it for you. BTW, I thought, in the case of the GFCI's, that the circuit had to be dedicated and go directly back to the fuse/breaker box for them to be effective. Is that not the case? If it is, I don't see them as an effective alternative on a 100+ year old system where circuits can/have been tapped at numerous places for additional outlets/switches. JMHO

Jamie Hall

GFCI sockets are fine on a branch circuit, and will protect themselves and anything beyond them -- provided they have a ground themselves, and the ground continues on beyond.

And @Fred you are quite correct -- if the insulation is deteriorated so that it's cracked (or coming off!) it should be replaced. However, this isn't limited to K&T, and where folks can really get into trouble is with a fully loaded circuit, using Romex or one of the other plastic insulated stuff, buried in a wall, and it has gotten wet or, worse, chewed. Red squirrels. Mice. Rats. Whatever. There you need an arc fault circuit breaker for protection. They are required for new work in residential circuits 20 amps and under.

They aren't cheap.

BobC

There is a house a couple of blocks from me that had the best knob and tubing I have ever seen. I inspected it for a friend and was amazed that it was still in perfect shape at well over 80 years old (at that time). This house had beautiful carved pocket doors in the public rooms, exquisite craftsmanship.

I told him it can't be touched or added on to. Anything that needs heavy power should be supplied by more modern grounded wiring. That house sold over a decade ago and I have no idea what the wiring there is now.

As to fuse boxes, I consider them safer than most circuit breaker panels I have seen. If nobody does anything stupid they are safe. I've seen ceramic fuse boxes from the 20's that were better constructed than any modern circuit breaker panels available today for houses.

Bob

ChrisJ

Jamie Hall said:

GFCI sockets are fine on a branch circuit, and will protect themselves and anything beyond them -- provided they have a ground themselves, and the ground continues on beyond.

And @Fred you are quite correct -- if the insulation is deteriorated so that it's cracked (or coming off!) it should be replaced. However, this isn't limited to K&T, and where folks can really get into trouble is with a fully loaded circuit, using Romex or one of the other plastic insulated stuff, buried in a wall, and it has gotten wet or, worse, chewed. Red squirrels. Mice. Rats. Whatever. There you need an arc fault circuit breaker for protection. They are required for new work in residential circuits 20 amps and under.

They aren't cheap.

Perhaps I'm not understanding Jamie, but GFCIs do not need a ground to operate, nor does code require it. As someone said, you may need to label it as such I'm not sure.

But it's considered an acceptable and safe work around when no grounds are to be had.

This is also why I put a GFCI plug on my monitor top. I didn't want to ground it for cosmetic reasons, but I wanted some protection, so I went with a 2 prong GFCI plug, like used on a blow drier.

Jamie Hall

Useful article on the subject of a GFCI in an ungrounded application: http://ecmweb.com/content/replacing-2-wire-ungrounded-receptacles

It is an exception to code, for rework on two wire ungrounded circuits. Sorry about that, @ChrisJ -- I wasn't thinking of that specific exception.

Although I perhaps should have been -- another property I do some care for, in Massachusetts, was built in 1964 -- and has no grounded circuits anywhere. I'm not sure how they got away with it...

EBEBRATT-Ed

A GFCI receptacle senses the current on the hot and the current on the neutral. They have to balance. If they don't the gfci trips. That's why there's an exception to use them on an ungrounded 2 wire circuit. If any current leaks to ground the GFCI goes out of balance and trips.

By the way BX is still legal to use @Jamie Hall is correct that BX uses the armored cable as the equipment ground. That's why some consider it "not the best" wiring method because it relies on the locknuts and connectors to carry a ground (and you know what that's like) Now they have "MC" cable which is basically the same as BX except it has a insulated green ground wire in it. Don't see it much in residential but is widely used in commercial work. It's available with a steel or aluminum armor jacket (250ft coil of steel weighs a bit the alum is nice and light)

There's some old romex around that had no ground wire as well. It was K & Ts replacement and even up into the 60s the ground wire inside romex was not always full size #14 would have a #16 ground.

@Jamie Hall not sure when grounded circuits became a requirement (I'm old but not that old) but my house built in 55" had two wire receptacles and my folks house built in 68" was all grounded so based on other house I have seen and done wiring in early 60s is my guess

The old rubber wire will last forever if the insulation has not been overheated by ambient or circuit load. If it is forget it.

How many have changed and old stack switch wired with the old stuff? Being near the flue pipe the insulation usually crumbled off the wire.

Steamhead

EBEBRATT-Ed said:

How many have changed and old stack switch wired with the old stuff? Being near the flue pipe the insulation usually crumbled off the wire.

Yet another reason to go to a 15-second cad-cell primary.

JUGHNE

The 1965 NEC code book I started with simply states that if you have a grounding outlet it needs some method of grounding.
Can't really see where it implies you have to have 3 prong outlets. Perhaps the next code cycle required the 3 wire, not every jurisdiction would adopt the new code in the year it came out.

The 2014 Codes states that all 15/20 amp outlets must have grounding with the 3rd prong. (Not worded that simply, but after all, this is the code book of exceptions)
Wiring houses in 1965 2 wire romex was the norm.
In the city (inspected) in 1969 3 wire romex was the norm.
At that time 2 wire was used for switch legs and 3 wire for outlets.....I first worked for a real penny pincher so we had to drag in 14-2 and 14-2-G boxes.

Going back to the 1950's in the rural areas when the REA power came to the farms, they required only grounding outlets in the basement for the washer and water pump. Cable with a bare wire was apparently not available so they would install 12-3 romex and use the red for a grounding wire. I have seen this quite often. Also they required fustats inserts to avoid over fusing.

ChrisJ

The 1958 house I grew up in had that black\green romex and all of it had grounds, except the grounds were wrapped around a nail in the box and 2 prong receptacles were installed.


One thing odd that I still cannot confirm, or even understand is my dad said the electrician that came out to swap a main breaker for him told him the two breakers plugged into the "Range" section of the QO panel were still hot when the main was off. It was a small 100A panel, maybe 12 positions? The double pole main took up two locations in the left column at the top and the Range section was opposite of it in the right column. The electrician claimed it was a work around when electric stoves came out.

I cannot for the life of me understand why that would've been, even our neighbors 1920s 60A Federal Pacific fuse panel has the Range fuses running through the main fuses.

I'm thinking the electrician was full of beans.

JUGHNE

Was that romex plastic sheathed? It could have been replaced since the 1958 original. Or with your location much closer to modern technology than mine you were more advanced.

As for the panel, what was popular was called a "split buss" panel. The main lugs were rated usually 125 amp. The top 12 spaces were fed by the lugs only.....no breaker. A factory installed 60 amp 2 pole was installed in 2 of these 12 spaces with it's load side connect to the bottom half of 12 or more CB spaces.
That left you with 5 more 2 pole CB spaces on top.
Your 120 VAC CB's were protected by the factory 60 amp 2 pole.
So, above was the range, water heater, dryer, AC, etc.

Code requirements were and still are that no more than 6 switches will disconnect the entire service.....and they must be grouped together within reason, this panel meant that requirement.

Why not a main CB.......if you price 2 pole CB's, the price jumps once your above 60 amp. This difference was at one time much more than now. Still a 125 Amp main is a lot more than 60A or lower. The manufacturer was much more competitive with split buss than compared to any panel with a 125/150 main.

Your neighbor's 60 amp FPE was just that. The range also ran thur the 60 amp main. Then you could buy a 100 amp panel that looked just about like that. However the range pull out fuses did not go thru that main. The main covered all the plug fuses below and the range was on it's own....another split buss.
Should be fed by 100amp #4 AWG service entrance cable.......seldom was......usually #6 SEC. Cable a little warm, but you usually never blew the 60 amp main so momma was happy. We all know what that means.

Electricians are never full of beans.....maybe something else, but not beans.

EBEBRATT-Ed

No @ChrisJ the electrician was correct. There are a lot of panels both fuse and breaker types that had multiple disconnects.

The old "Main Range & 4" fuse panel had a main fuse pull out that was 60 amp. The wires (incoming) from the meter terminate on top of that pull out. Pull out the main ...everything is dead. The range pull out is fed off the LOAD side of the 60a main pull out as are the 4 plug fuses for the 120 volt circuits. Sometimes 8 plug fuses.

The panel in my house looks the same as the one above except it is a 100 amp panel. Has the same two pull outs, Main & Range.

The difference is that the range pull out is fed from the line side of the 60 amp pull out. So in effect there are two disconnects, 60 amp pull out feeds 120 volt fuses, 60 am pull out (with 40s in it) does the range.

The code still allows no more than 6 disconnects to de energize a building, 6 hand movements. All disconnects and or circuit breakers must be grouped closely together in the same location and marked.

I know Federal Pacific (no surprise) made cb panels that had no main breaker but used the 6 disconnect rule.

I am sure there are others

perfectly legal. But inspectors don't like this rule but can't do anything about it.

Example: a commercial building with a fire pump. 1 disconnect to kill the whole building, and 1 disconnect for the fire pump so the fireman can kill the building and let the fire pump run

JUGHNE

So Ed, what is the arc fault rating of the main/range fuse pull out panels? No label most likely.
I used to reuse or re-feed these as a sub-panel and now looking back realize it was a dis-service to the customer. However money was always tight and why change something that worked.

Fred

I think they probably over engineered my electric when it was re-wired in the mid to late 1960's In addition to these panels in the basement, there are two more panels, just like the pair in the basement. One on the First floor and one on the second floor. The third floor is feed off of the second floor panel. It's 200 AMP Service.

ChrisJ

So, we had 100A service in that house.
The electrician put a 100A main in the panel, and on top of that it had two 20A breakers in the "Range" slot.

So, 100A service running 120A? Was he correct to do that as well?

It happened when my dad sold the house, the buyer's home inspector wanted the 50A it had in it swapped for a 100A main.

ChrisJ

@Fred
Well, when you're rich and own a mansion...............



Here's mine with the sub panel I added because I ran out of room. I'm almost there, again.

This was before I added all of the labels. I don't have one showing both since I added them.

Jamie Hall

If you want to have fun and games with fuse panels, try a farm -- or the main place I care for (which is a farm and museum)! The local code insisted on an outdoor circuit breaker which kills everything, including the water pump (idiots) -- 200 amps. Then there is the generator changeover switch. Then there is the main fuse pair, likewise 200 amps. Then there are 5 (five) fuse boxes (all fusestat) and one circuit breaker box for the main building, each with its own fused disconnect (except the breaker box -- which has a main breaker). Then each of the dependencies (three of them) has its own sub box, each with its own fused disconnect... I've got a little list, posted, of what fuse/breaker disconnects what. Never keep it straight otherwise!

Bottom line on fuse or breaker boxes such as the ones which @EBEBRATT-Ed was mentioning -- that's what those cute little screwdrivers with a neon bulb are for. Never, ever assume that a wire is dead without testing it. I don't care what colour it is!

Fred

ChrisJ said:

@Fred
Well, when you're rich and own a mansion...............

@ChrisJ , at the time this electric was upgraded, the house was owned by Lutheran Social Services and was converted to a Nursing Home. I'm sure they had a heavy electric load and had to meet commercial codes. They were here about 15 years and built a 400 to 500 bed facility/Campus just south of town. This area became a Historic District in 1983 and I bought the home and restored it back to a single family home in 1991.

EBEBRATT-Ed

@JUGHNE I was told all the old stuff if it isn't labled is assumed to be 10,000 amps interrupting capacity

@Fred and that picture I do believe is the old rubber covered wire in that disconnect. Same as the K & T stuff only in conduit. And OMG they forgot to color or tape the neutral leaving the disconnect white HOLY VIOLATION. Also the equipment ground is the conduit not a wire. Typical of the way everything was wired back then and nothing wrong with it.

@ChrisJ Contrary to popular belief on a service the wire size doesn't have to match the main breaker or fuse size. The wire size only has to match or be larger than the calculated load.

Example: a three family house you calculate the total load for three floors and it will run on 4/0 Aluminum SE cable (nominal 200 amp) wire. So you drop down from the weather head with the 4/0 and feed a 3 gang meter socket (1meter for each floor).

Each floor will run on a 100amp panel which (in most cases) is the smallest service you can install. Each panel has a 100 amp main breaker

So now you have 200 amp cable feeding a potential load with (3) 100 am breakers attachéd to it

People think when you wire to "code" your getting a Caddiliac Job. It's not. The electrical code is the minimum requirement and again because it calculates out that way it's fine

GW

Wire size: when installing ac system, one electrian I work with says you need to size the wire according to the breaker. Another electrician says there a "Start Up" factor so the breaker size is a bit bigger than it needs to be just for start up, and the wire can by rated for the MCA plus 20%????? I hope I'm recalling this correctly

ChrisJ

EBEBRATT-Ed said:

@JUGHNE I was told all the old stuff if it isn't labled is assumed to be 10,000 amps interrupting capacity

@Fred and that picture I do believe is the old rubber covered wire in that disconnect. Same as the K & T stuff only in conduit. And OMG they forgot to color or tape the neutral leaving the disconnect white HOLY VIOLATION. Also the equipment ground is the conduit not a wire. Typical of the way everything was wired back then and nothing wrong with it.

@ChrisJ Contrary to popular belief on a service the wire size doesn't have to match the main breaker or fuse size. The wire size only has to match or be larger than the calculated load.

Example: a three family house you calculate the total load for three floors and it will run on 4/0 Aluminum SE cable (nominal 200 amp) wire. So you drop down from the weather head with the 4/0 and feed a 3 gang meter socket (1meter for each floor).

Each floor will run on a 100amp panel which (in most cases) is the smallest service you can install. Each panel has a 100 amp main breaker

So now you have 200 amp cable feeding a potential load with (3) 100 am breakers attachéd to it

People think when you wire to "code" your getting a Caddiliac Job. It's not. The electrical code is the minimum requirement and again because it calculates out that way it's fine

Similar to the 25kva pole pig outside of my house feeding us + two duplexes. 25kva is enough to feed only my house with 100A service, and yet, it's feeding 5 families.


It used to be worse, when we first moved in I measured 105V on one leg during the summer at my panel and complained. Next thing you know, we got a transformer right outside our door feeding just 3 houses.

ChrisJ

GW said:

Wire size: when installing ac system, one electrian I work with says you need to size the wire according to the breaker. Another electrician says there a "Start Up" factor so the breaker size is a bit bigger than it needs to be just for start up, and the wire can by rated for the MCA plus 20%????? I hope I'm recalling this correctly

Startup which I assume would be similar to LRA does matter, as does the wire distance. A 20A circuit breaker will deliver something like 10,000A? for a very short burst. I'd have to look it up, but it's high for a fraction of a second.

Though I ran 10-2 for my 3 ton unit, I considered going one size larger as it's 50 feet.