Know and tube worries

[SwierkE]

Hi all! I've finally found my dream old home, 2.5 story 1872 victorian (one that hasn't been gutted and turned into an open floor plan.)

Anyways, it has hot knob and tube as well as cloth and modern wiring. It seems to in decent condition as far as I can tell, but not sure exactly what I should be looking for. How worried should I be?

Thanks!

[Willa]

I don't know about US or state regulations (I'm in Canada). When my ex and I bought our former home (1873 fixer upper) there was some knob and tube. There were hassles with the insurance company, who had also forced the elderly former owners to upgrade their electrical system.

We had hassles with this insurance company almost immediately, who cancelled our home insurance on the basis of murets (sp ?) on the light over the kitchen sink, as done by the 80 y/o previous owner. This light was removed the first day we took possession of the house. The insurance co. cancelled the home insurance policy on the basis of the inspection report, and we had to battle with them to re-instate it. We got the same house inspector to come back, who wrote a letter on our behalf. It was nuts. Eventually the insurance was resumed with this company. (Due to the age of the house, there were issues with getting home insurance for a bunch of puzzling reasons, which is why we didn't attempt to shop around.)

It is probably in your best interests to plan to get the house rewired, and include this expense in your budget. There's no reason to maintain the knob and tube in the interests of historical preservation, for example. As far as I know there is no immediate danger with k&t as long as you do not overload the house.

[phil]

I'd call in a real electrician and get some estimates. You can pull in new wiring without tearing the walls apart, or if you plan to insulate, (is there any?) then one way is to open the walls up add wiring, insulate, and drywall , in some cases people want to retain the plaster and if it's historically significant there are grounds to want to retain as much originality as possible. I wont try to sway you on that, just making some decisions apparent.

other things like if the wiring service and electrical panel need upgrading you might add that to the list. we use more power today than back in the old times. if you want to use AC or electric heat that's a factor.

K and T has no grounds , the boxes aren't grounded , the electricain may change breakers to spark fault or ark fault ones as a temporary measure. I changed all the electrical boxes not just the wire. some boxes can be screwed from inside so you dot have to tear the wall open others are made to nail to the studs from the outside of the box during a new build. lots of differnet box types some are plastic, some are metal , many different sizes and confgurations. they need to be large enough for the number of wires and connectors inside them the electrician will have tables for that.

one danger is that K and T was often connected between boxes and I found lots that were taped up not soldered, inside walls above the outdoor lights , in weird places I couldnt see until I pulled it out. that's definitely a fire waiting to happen.

lots of times in our old houses the wires ran in the attic then to the meter so look for any signs those wires were connected into. in lots of cases they were tied to to get free power. Its those modifications you really have to look closely at.

This is one area I wouldnt keep original , just replace it, get it inspected, you can change back to things like old switch covers or repro push button switches or reconditioned lamps and stuff later but just use new and UL approved parts and the inspector won't be so nervous about what you are doing.

while considering all this think about how many plugs you want how many lights. Youll need fire detectors on each floor, spark fault breakers for bedrooom plugs probably a lot more kitchen outlets. each outlet in the kitchen needs it's own breaker none should share a breaker so if yoiu have a box with 4 outlets , thats 4 breakers righ tere. fridge cant' share its circuit. so plan to pull lots of wire to the kitchen to make it meet code. I put a 200 amp panel so I needed to put heavier wires from the meter to the pole for that. but I can now have electric heat if I want or build a shop and run a sub panel. the panel isn't the main cost the wires are. pick a good brand , I like square D, dont cheap out and get whats common not some off brand.

old houses did not have many plugs. now youll want one on each wall roughly.. mine were in the baseboards and I moved them all so the bottom of the box is 11 inches from the floor to miss the baseboards to avoid butchering the baseboards more. I patched any old outlet holes. likewise you'll want all the switches the same height from the floor for consistency.. you might draw where they will go on the wall but keep them beside studs.

Your codes may be a bit different. here I rewired it myself under a homeowners permit but I had my brother with his electrical ticket supervise me , It might not be normal in your area to do that you could check if that's a consideration.

There are still many houses with 100 year old wires. You may or may not be forced to upgrade but I think it gave me lot of peace of mind and as I pulled the old junk out I found reasons why the upgrade really made sense. i had others saying aww its fine. its still safe , mine was not and it didn't look very modified. It was done professionally in the beginning but people do stuff they shouldn't sometimes. so you need to play detective if you choose to keep it in place.

you have to make these decisions on other factors like the budget, If the roof leaks that might come first or if the sewer plugs, or if you have water issues that are causing damage. its easy to o 6 different ways at once and it can be overwhelming. dont' start moving the walls or making major mods or replacing windows. usually others here advise to live in it a year and you'll have thought things through more. Insurance can be an issue and it will for others if you sell so the upgrade is probably a good investment in the value.


plumbing is another big deal. old copper pipes that look black from age may be worn out inside and could burst. check if there is a pressure regulator or if you have the whole house at street pressure. sewer plugs fill with goop after years of use. old sewers collapse or get tree root issues. having a plumber in to inspect that may also be worthwhile.

dont panic right away, take time to research look at the budget and try to form a realistic timeline that you can budget for. Its so easy to open more than you can handle. guess at the timeline and double the time. try to get on the same page with your spouse this stuff can cause serious issues if you have different agendas. Talk to your insurance company, see what they can do as far as right now. try to bide time to plan it so it's practical for you.

you may find electricians or plumbers or other trades that will work with you and let you do some of the work , it varies and so do the skills of homeowners so what makes sense to one isn't right for another. some electricians would want no part of someone unqualified doing work as it may be against regulations, like if you break the insulation pulling wire that could be an issue and the electrician could risk liability as hes responsible for the whole job. but some would be really careful not to and get some buy in that they are doing it right . Some may find the electrician lets them carefully pull wires in and let them make the connections. you might be able to open access routs etc. some owners are more savvy about what they are doing and a lot happens not under permit. this is one thing I'd do under a real permit and have it recognized by insurance however you do it.

I was allowed to keep my old system running until I had a new panel wires outlets meter all new and when the inspector was happy then he let me move the main power wires then cut out any K and T left visible. he didn't care if there was still some wire inside walls as it wouldn't be reconnected. some of the old locations for switches etc needed to be switched so I had lots running on extension cords towards the end. You may not have that issue if you call someone and they do it in a week or so but i needed time so think about how you can overlap the usage or if you can walk out to let them just go at it.

network , phone cable.. wire for window sensors door sensors for alarm, doorbell, wires for security cameras , I ran lots your mileage may vary we dont need as much cat 5 or cable runs today with better wireless. I ran it all to a panel just for that. You can call it a smart panel. point is if you are opening walls and pulling wire you might want some of it installed. or not.

there is other stuff , my living room never had ceiling lights , I chose to not have them but I wired two plugs in and used two switches so I can still plug lamps in and use the room light switches. one each of those I made one outlet switched, one always on. your furnace should have a switch near the door , the plumbing heat pipes, any metal needs to be bonded to the electrical.

Your codes may vary a little so none of this is gospel ok? Im in Canada too and there are some differences but its not completely different here.

Id suggest first drawing a plan where you want the outlets and switches and where the panel will be. do a sketch. then if you call and electrician in you can talk about it more and make sure its clear what he's doing so you dont have a conflict of expectations. remember if you do an upgrade it needs to be within modern regulations.

about half my panel is the kitchen, bedrooms don't need so much. dont forget the arbage disposal or the fire detector wiring you might want CO sensors. outside plugs need to be on arc fault breakers and the bathroom outlet may have one combined into the outlet. spark fault breakers in bedroom plugs is newer code you could find it is different by area but if you group them in the original plan that might mean just one breaker and they are 100 or so apiece. so how you plan each run is important. if yoiu blow an outlet's breaker it shouldn't' kill the room lights. once you have an idea what you want then the electician can help with further planning. you might need to open a path to go from basement to attic I just opened one stufd bayt for all the wiring ot pass between floors , also needed that to bilt the mast to the house. I installed an electrical mast that goes up through the roof. thats the more desired way by the inspector , many houses just have it tied to the side of the house or something.
and that might meet code. to support the largetr panel I had to provide a meter past the gooseneck on the wiring mast , past there the power company looks after the pole wires. in mine those wires are 000 (three ought) big cables. the copper is expensive. new dryer run , new stove outlet, those are big ones too. I have gas hot water electric is an option or some loose the tank and go to on demand hot water , it occupes less space. they can be noisy if they are located near where you sleep . you can add a gadget so if you get a water leak it shuts the water down after a certain period of constant flow. you might want electric for AC maybe a 20 amp breaker. i added larger (red wires) for that. It can double as a heater since you wont use both at the same time.

ever want ot add a suite? you can start planning if that's an option for you. If you do you may need 5/8ths fireproof drywall between the suite and the house. and a separate heat system for the suite.

alunimum wire, I dont know I dont like the idea but it might be ok with code. You can find out more.

its ugly but in certain cases you can run on the surface if you put it in conduit. thats more common in industrial buildings with concrete walls.


phil

[1918ColonialRevival]

Insurance companies have made K&T into a bogeyman. The problem isn't the K&T itself - it's the number and capacity of the circuits that make up the electrical service and any modifications that were made along the way. In the early 1900s, most houses had 30 amp electrical service with two to four circuits servicing the entire house. As more electrical appliances went mainstream, power needs increased and before long, 60 amp service became the standard, then 100 amps, then 200. A common thing to find is that additional circuits were simply added and existing wiring was left alone instead of updating the whole system (such as putting each room on its own circuit). I've seen half of a house wired to a single 15 amp circuit before, which is an accident waiting to happen.

The first step in evaluating a house's wiring is to map it. First, note whether your service is 60, 100, or 200 amps - it will say on the outside of the box. Anything less than 100 amps (which became the standard after WWII) should be upgraded unless you are a minimalist in terms of electrical appliances. Start at the service panel and turn off one circuit at a time by either turning the breaker switch or removing the fuse depending on what you have. Go through the house and note which lights and outlets are turned off with each circuit. If you find that one circuit controls a large number of receptacles and/or appliances, that is a circuit that could potentially be overloaded easily. That would be a good place to start with re-wiring.

As you turn off different circuits, pull a few receptacles out of their boxes and inspect the wiring for signs of overheating, such as burned insulation. Again, high demand circuits in areas such as a kitchen will be where you will most likely find this kind of damage.

This will help you get a better idea of what you are dealing with and how much electrical work is an immediate need versus that which can wait.

[SwierkE]

First off you all are truly amazing and I'm humbled by all the help and information!! You have given me a lot of great suggestions and considerations. We are going back for a more in depth walk through this weekend and I'm bringing along my savvy father to help PRE-inspect. I'll relay all this info to him.

I'll definitely pay more attention in the attic and where they go. I remember my uncle telling a story how he tapped into the pole for free power, back in the 50s.

There is a new electrical box, and the previous owners labeled each circuit. I'll definitely want to check that its accurate. But I didnt see any on the screw fuse box or the knob and tube, so that will be fun to map. The kitchen has been updated, so I hope that's all new wiring....I hope.

[Gothichome]

SwierkE yes as others have mentioned K&T wiring as long as it is sound is not a big issue. It’s the messing about with that makes it a risk, as Colonial mentioned the biggest issue is circuits added on to and over loading the rating. Also as mentioned the insurance companies don’t like it. That I think will be the your issue in the short term should they ask, is getting insurance.
You have time, so no need to rush into a major rewire when you first move in. I do have one suggestion for you though, when you do upgrade to modern ground fault electrics remove every bit of the k&t. The insurance company inspector will write in their report ‘knob and tube present’ on his report even if it’s been abandoned.

[nhguy]

When we bought our place the listing said some K&T wiring. It should have said all knob and tube except in the basement where you can see the new wiring. We had an estimate and it came to $10K, which we felt was reasonable. We upgraded to a 200 amp panel, plus added a 100 amp panel in the attic and had underground wiring run to the carriage house and put a 100 amp panel there as well. We got insurance because we had the paperwork showing we were moving forward with the work. Our sale was cash and I don't know if we would have gotten financing should we have needed it. Most of the other buyers were scared off by all the work needed to be done their loss our gain.

[Willa]

One other thing to consider is that if the house has any fancy plaster details like medallions or crown molding (moulding ? I never get that right) you may have a slightly greater headache finding a sympathetic electrician.

In my former neighbourhood, there were many houses missing their medallions (and worse) because some dummy electrician said that he couldn't possibly work around that (untrue but it takes a little extra skill). The medallions would get SAWN OFF the ceiling and put in the trash ! This was even happening in the early 2000's.

I recently had to get some minor electrical work done in my late 1800's house. Even though the electrician also owned a house about the same age, he told me some untrue things about the plaster that he plainly didn't know. He claimed that the fibers in the plaster were asbestos. In plaster that old it is horsehair - asbestos was big in the mid 20th c. so some plaster of that age might have those fibres.

It would be prudent to aquaint yourself with the what's what of plaster and lath, and learn how to repair it. If you need to do any modifications to your house, no doubt you will encounter contractors who will tell all kinds of tales about plaster.

Stupid tv shows treat plaster like it is a terrible emergency that needs to be removed right now ! Dummy contractors will tell you that it is "dangerous" or that it can't be repaired or cannot even identify it by sight. There is zero reason to knock out the plaster to replace it with drywall.

If the house needs to be completely rewired, you will probably need to have patch type repairs adjacent to switches, etc. The challenge is to find the electrician who isn't going to ruthlessly smash up the walls because s/he doesn't know any better vs making neat incisions only where they need to go.

Finding a competent plasterer (vs someone who only knows how to install drywall) is also a challenge. A few are out there, or you can learn to DIY, though there's a learning curve.

[1918ColonialRevival]

One other thing that I forgot to mention earlier - armored cable, sometimes called "BX" or "Greenfield" cable, has been around since 1899. Sometimes if a homeowner decided to spend a few extra bucks, you will find this in installations going back to the turn of the 20th century. My experience has been this type of cable usually ages very well provided it hasn't been overloaded, and is remarkably similar to armored cable manufactured today, with the exception that the modern armored cable has the addition of a ground wire where the metal sheathing (unintentionally) acts as a ground on the older stuff and the individual wires are insulated with PVC jacketing as opposed to cloth and vulcanized rubber.

Wiring isn't tough to learn, but some people are intimidated by it. I highly recommend learning to re-wire yourself versus having someone come in and make a mess. All "professionals" are not created equal. One time a cable installer wanted to drill through the oak floors in my living room and hallway. I politely showed the clown the door and finished the job myself.

[phil]

it might help to understand how to fish a wire in. You can lock out the panle or at least switch it off and make sure no one turns it on.. pull the outlet or switch out, pull the box out of the wall.

Next you can drill with a long drill bit , like 5 feet long down inside the wall or up , through the sillplate. thats the 2x4 that the other 2x4's are nailed into. you can go through to the next floor and pick up from here. a word of caution though. You have to be sure if you are drilling any holes that you dont hit wiring.
to get the wire down through the wall and the hole you use a fish tape, you can use stiff wire or buy one or they use fiberglass poles that screw together sometimes. If you can pull a wire or string then you can tie that to the cable.

on the number of boxes. i think code here says you can put 10 might be 11 or 12 on one breaker. the important thing is the load. stuff like bedside lamps clock radios wont' draw huge amounts. stuff like motors and heaters a vacuum cleaner do draw more. toasters blenders coffee pots microwaves draw lots. more plugs dont necessarily put more load but may be for convenience but if you have lots in one run of course there is more opportunity to overload it. you can actually check by running things and using a clamp meter around the wire in the panel if you want specs of the draw on an individual circuit. some meters can even be left to record peaks or map a time pattern. asa n example I put a box with 6 outlets behind my TV because I knew that was an are where I may use a power bar to get enough plugs, but that isn't drawing a huge amount of current.

I like to use a vacuum cleaner to find breakers. plug it in then go to the panel then you can hear it rather than running back and forth. you could use a radio. I put little number tags on my outlets to the corresponding breaker and made a map to put near the panel because to make a list on a little tag in the box is difficult. I still put a short description.

modern wiring should never be spliced between the panel and a box. the connections should all be in boxes. If you see any connected or taped up mid length thats suspicious. If you find suspicious stuff then look more deeply.

electricians are good at looping their wires, using pigtails and keeping the connections neat and tidy in boxes. if they are twisted in a weird way that's a sure sign someone inexperienced or uncaring did it. I do all mine wiht pigtails and you can pull any of my outlets out of the box to work on them. if the wires need to be extended you make new pigtails.

if a wire is too short from multiple people working on it over time, that's an issue because you cant' make a connection in the wall. then you have to install a box to make the connections in or run a new wire back to the panel. the junction box is not permitted to be hidden.

if you just go look at the panel look at the wires entering. Youll see if they are K and T wires, some may be silver cloth covered or green cloth covered, Thats older. most of the new stuff is romex and white.

the wire comes as "tw wire" which is black white and ground. or three wire , black red white and ground.
note the copper ground is not counted.

to save wire you can use a double breaker with three wire. whats going on there is each breaker supplies the hot and they are on opposite sides of the panel. the current runs through that breaker and the corresponding red or black. The return path is through the same neutral. this is allowed because the two circuits are out of phase with each other. when you staple the wire it has to be stapled at I think 3 feet , but you can put them closer. the special shaped wire staples can hold either two of the normal 2 wire romex or one of the round 3 wire cables.
BX cable is well protected. I agree the failures are not usually the wire itself but the silly things people sometimes do.
in industrial wiroing like hanging cables and such we often use cab tire , its the thick black rubber covered stuff. Id use that for anything getting walked on like your tablesaw but not in house wiring. some wiring can be buried, BX might fit into that. you'll check if you bury any cables.

in places with cement walls and exposed conduit they usually run the wires inside the conduit , the pipe is grounded. no insulation. the insulation itself protects the wire but also hampers the wires ability to cool. so they dont usually pull insulated wire in the conduit.

if you wan to play detective you can look at the panel you'll see any old wires. you'll know something is fishy if you see a new wire entering the panel and then look at the box its feeding and see a different type of wire. If you see this you need to find out how they connected the wire. sometimes people drywall drive scres into the wire, it happens then you can see how a drywaller noit being an electricain may cover this and continue to save face. it happens.

usually it isn't all fishy.. you cna usually tell by look ing at the panel and the type of wire and get an ide of the age and that may give indication when past upgrades happened. If you see green wire that is grounded , it could be ok it may be from the 50's and still fine and safe. If they are all white plastic covered then its a modern upgrade.

the outlets wear, the metal the prongs touch get blackened, then they are poor conductors, then they get hot due to the resistance then they loose their springiness and then they loose contact more. see the vicious circle here ? Id just change any old ones. You are not allowed to install grounded plugs in systems that dont have a ground but you can still get two prong outlets.
you can pick up an outlet checker at the building store for around 10 bucks , plug that into an outlet and it'll show if there is a wiring fault like no ground or the hot and ground mixed up. firs thing Id do is get one of those , If you see a lot of issues with that then look closer. If it's OK then at least it ins't wired all incorrectly so far as the little tool can check.

there is a little tool that basicly introduces a radio signal into the wire an electrician would have one. wiht that you can plug into a circuit then check with a sensor for this radio siugnal , thats another way of identifying where wires go.

most electricians carry what is often called a "sniffer" in their pocket. its a thing the size of a sharpie. if you hold it near a wire it will start beeping if the wire is hot. good practice to have one they are cheap. before you touch any wire use the sniffer as a check. I usually use a meter to further verify so I dont make a mistake with whether something is energized. if you take the sniffer and rub it against your clothes it makes a beep because it is sensing the static charge,, so often you will check the device is working in this manor. likewise if you are using a meter , go connect it to a live outlet , see it is reading right and then use it to do your wiring checks. you dont wan to get a shock because you had a bad meter or dead battery or if the meter has a switch it could be on the wrong setting so verify it works to be safe.

Im all for doing it myself if I can. I dont like to try to decide who else is qualified. Technically only electricians have the authority to install or change the wiring system but I think really what is important is thet you stop and learn if you are confused or uncertain in any way.

an example I was called to work on some 24 volt circuits in an area they are all running in conduit and surface mount boxes. it involves a timer and some electronics and a keyswitch , they lost the keys and wanted me to put buttons in to replace the keys,, anyway i can technically do it, but because it's at work and I am not a ticketed electrician I call one to work with me. That way I'm not liable and it is generally good practice not to try to overlap into someone else's job so it is partly out of respect as well. At home I think a bit differently because it's a different budget and my own risk.

its only my intention to try to help and not to try to encourage anyone to go in and do wiring and create a safety issue, but I do understand how some have enough technical skill in the area that they may be able to do basic mods with out creating any danger. others may be tempted into a danger with advice.

If I contradicted anyone , of if I am giving any misinformation please do call me on it and from what others said above I'd say you are getting good info. If you work on stuff like this, Its your responsibility to be safe not others who post on the forum. Technically I think you need an electrician to do things legally but what you do in your own home is your business, that's just my opinion. I am not an Electrician.