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Can I upgrade from a fuse box to a main circuit breaker panel with knob & tube

Can I upgrade from a fuse box to a main circuit breaker panel with knob & tube

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Old 01-23-16, 01:43 AM
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Can I upgrade from a fuse box to a main circuit breaker panel with knob & tube

Sorry about this long post for a newbie forum member but its all kind of interrelated.

Primary question is: If I have K&T what are my chances to upgrade from a fuse panel to a new main breaker panel? And do I have to use AFCIs when I do this and will they work with my 2 wire K&T? From what I’ve read it seems to be a nonstarter and I have no recourse but to live with the inconvenience of fuses. Is this true? I would like to replace the 125 amp fuse panel/box with a 125 amp breaker panel.

If I can pass the above hurdle, how about this: There are a couple of, likely bootlegged, 1980s-ish 12-2 romex circuits in my fuse box. One for a 120v wall heater in the finished attic and a second 120v leading to an outbuilding. Does that make my chances even more dim with my AHJ.

Current service is a 125 amp fuse box with 3 separate 1960’s/80’s-ish breaker boxes tied into it for additional 240v circuits; dryer, water heater and detached garage. I have converted to gas so all the 240v appliances have or will soon go away and with CFLs & LEDs my electrical needs are much reduced. If I stay with 125 amp that should be plenty of capacity and I don't think I will have to change out my meter box or service wires, which in my case, would be quite difficult.

At my age I am not going to tear into walls for a rewire. I can buy a lot of fuses for the $10K+ it would cost for a contractor to do it. I just want the safey and convenience of a panel with modern breakers.

House built 1941, pretty good condition K&T throughout, without ground wire, of course. I am in Seattle on the 2014 NEC.

In 1980 I gutted and completely rewired another house all the way to the service drop so I consider myself a fearless but careful DIYer. There are so many new requirements now though. The issue that has me the most wary is whether it is even possible to upgrade to a panel with modern circuit breakers and AFCIs but still retain all the old K&T wiring and non grounded outlets. Thats the crux question but heres a couple more I’m wondering about:

I’ve traced all the wires in the existing panel. Specifically to pair up the neutrals with their hots of the various K&T circuits. Some pair up and don’t appear to share a neutral but I also found:

Two hot conductors from 2 branch circuits that share a neutral. They were wire nutted together in the panel box with a pigtail that went into one of the fuse terminals. Somewhere in the walls of this 3 story house the neutral branches off to feed both. From my reading shared neutrals are a non starter for an AFCI…. unless I can find where it splits in the walls and bring back separate neutrals for each circuit. Even if I could find the wye/tee, (and there might be other tees) I’ve read that work like this on K&T is not permitted by NEC. Is that true?

And is it ok to use wire nuts inside the main panel to make splices like the above?

3. There is one white wire in the main panels’ neutral buss that has no continuity with any other white wire in the panel, nor with ground. When I leave it disconnected all fixtures and outlets operate properly. What could this be? None the less I will still connect it to the neutral buss if I am allowed to upgrade to a new panel.

4. There is one circuit that has no neutral. I disconnected all white wires from the buss in the panel and turned on all the lights on that circuit and they operated normally! I plugged in a portable 1300 watt heater to the circuit and the lights dimmed a bit, maybe 5 or 10% less bright. I would consider this normal considering a heater load on this 15 amp circuit. I then disconnected the ground wire from the copper water pipe entering the house and the ground wire from the outside ground rod clamp and the lights on the circuit still operated the same brightness but after turning on the heater it dimmed, maybe a bit more, ~10 or 15% less bright, still not bad. Then I disconnected the main neutral feed from the meter box to the panel and the lights still operated normal brightness, though the heater dimmed them quite a bit more, maybe 25% less bright. Still not awful but not quite right either. I didn’t think to test for voltage, unfortunately. I don’t think there is any other place in the house where a neutral for this circuit could be connected to a water pipe to complete a circuit because I have converted to pex. I guess the circuits’ neutral could be connected to a bx cable somewhere. There are several runs of metal bx cable clamped to the panel so maybe the aggregate of those could form a neutral/ground path for this circuit, one bx cable rests on the concrete crawl space floor and another touches the concrete chimney, and there could be other concrete contact points as well. Any ideas how this circuit finds it way to ground/neutral?

5. There are 3 mystery #14 cotton/mineral/asphalt K&T wires in the crawl space, none of them are supported by a knob or tube as they exit the wall cavity from above:
a. one is red and is clamped to the galvanized water pipe 18” away
b. another is white and is also clamped to the galvanized water pipe 18” away. When I changed to pex I connected all the bits of galvanized pipe I didn’t remove to the panel’s ground buss with a green #12 wire. However, I disconnected this wire for my continuity tests below.
c. Another white one is clamped to the metal bx cable of the electric range.
When I unclamped them from the water pipe/bx and tested for continuity none of them were continuous with any of the the others, nor with ground, nor with any of the white neutral wires in the main breaker panel, (I was hoping that they would be neutrals for a branch circuit). Leaving them detached had no effect on the operation of any of the fixtures or outlets in the house, though I did not put a load on them such as with a heater. The red wire is the only instance of a red wire in the house not being hot. Red, blue and black have all been used/spliced/interchanged as 120v hot conductors in this house with no rhyme or reason that I can see. All neutral wires have been white.

6. Another hope I have is to feed a 20 space, 100 amp, sub panel in the basement with a 6-3 nm cable from a 50 amp breaker in the main panel. I am remodeling the basement for a possible future mother in law apartment. I want to run all the proper kitchen, bath, afci, gfci, and branch circuits for this. But if NEC does not allow me to install a new main breaker panel as above then I would like to use the old 240v breaker box from the old electric dryer to feed the new basement sub panel. Does NEC allow this?

7. For existing 2 prong K&T receptacles does NEC allow me to fish green ground wires up thru walls, where possible, into the existing metal boxes to install 3 prong receptacles? I would lead the green wires back to the main panel and connect to the existing buss.

Other: The electric range is in the main panel on a pullout cartridge fuse block. It will be replaced with a gas range eventually. A second pullout cartridge fuse block is the ‘main’ that feeds the individually fused branch circuits.

Thank you for your advice

Eric
 
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  #2  
Old 01-23-16, 02:35 AM
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I'll leave your main questions to the pros but:
At my age I am not going to tear into walls for a rewire.
You don't normally need to tear into walls to rewire. Old wires are abandoned in place and new cables are fished.
 
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Old 01-23-16, 05:52 AM
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Usually it is easy to install a new breaker panel next to the old fuse box. You run a feeder from the top of the fuse box (where the original service wires or cables entered) over to a double breaker (here about 125 amps) in one side of the breaker box.

The fuse box remains intact to begin with. At your leisure you would run (may be DIY) modern wiring (Romex cables, etc.) from the new breaker box to gradually (one branch circuit at a time) replace the knob and tube wiring coming out of the fuse box.

Things may be a little more complicated if there isn't enough space to install the new breaker box and have the service cable reach it given the distance limit from where the service cable enters the house.

It is also acceptable to have the new breaker box some distance from the fuse box with a longer (here, 125 amp) cable (may be DIY) connecting the two and have a brand new service entrance, weatherhead, and cable (professionally installed).

The advantage of installing the new breaker box while the old fuse box is still intact is that power will have to be shut off for a shorter time.
 
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Old 01-23-16, 07:52 AM
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If you are replacing fuses on a regular basis you are overloading your circuits. You need to add more circuits, another reason to change the panel.

I’ve read that work like this on K&T is not permitted by NEC. Is that true?
Local rules apply for AFCI requirements. In our area any circuit that is tampered with is required to be AFCI protected per NEC. Square D homeline and Siemens make two pole AFCI breakers that work fine on multi wire circuits. The Siemens are less expensive. However if there is an arc fault issue on the K&T circuit the breaker will not hold and the circuit will need to be replaced. I have had that happen on one job but the inspector let it slide and allowed us to install a regular breaker.

And is it ok to use wire nuts inside the main panel to make splices like the above?
Yes, in the US.

#3 It could have been part of an abandoned circuit.

#4 It obviously is completing the circuit from someplace. Perhaps a mixed up neutral in another box. This could be bad as you might have a doubled up neutral. (two hots of the same leg on the same neutral)

#5 Somebody must have not cared about color coding.

#6 That sounds fine.

#7 Yes.
 
  #5  
Old 01-23-16, 09:15 AM
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I don't think I will have to change out my meter box
Have the meter socket and service entrance wiring ever been changed or upgraded? If not, I can assure you they should be. I have yet to see a 75 year old socket or service entrance wiring that didn't need replacing.
 
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Old 01-23-16, 01:12 PM
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My first thought is to suggest that you move out of Seattle. I was born and raised in Seattle but I moved out some 38 years ago and have never regretted it one bit. I also retired more than ten years ago and so it has been close to twenty years since I have helped anyone do electrical work in Seattle with one exception.

I suggest that you incorporate the suggestions of CasualJoe and AllanJ and go with an all new service entrance. New mast, new conduit, new meter base and a 200 ampere full-size circuit breaker panel if possible. I don't know if this special requirement is still enforced but at one time so many people were converting to electric heat that Seattle City Light (SCL) was requiring anyone that upgraded to a 200 ampere service to also upgrade the thermal insulation in a home. If that is still in effect then staying with a 125 ampere service does make sense although I would still do the new mast and meter base and, of course, new conductors.

This is, absolutely, a job requiring a permit. Some fifteen-twenty years ago (I'm getting too old for this) SCL was somewhat separated from the process of new service installs by the formation of Seattle Public Utilities (SPU) that does the initial investigations and has the initial requirements. Honestly, I don't know how it works now other than it is a bigger hassle than it used to be. I think that the permits are good for six months but possibly for as long as a year. You might still be able to get a permit for only a service change/upgrade and then later on need to get permits (or not, if you want to live on the wild side) for changes to the branch circuits. You can use the old fuse box as a junction box for connecting the old circuits to the new circuit breakers.

Lots more, but I need to move on.
 
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Old 01-23-16, 02:21 PM
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Wow, I go to bed at 2am and 6 hours later I wake up to a bunch of great replies. Thank you.

CasualJoe,

1 I’m curious why you say I should change the meter and socket. When you say socket do you mean just the guts in the box or the whole box?

Guts would be easy, but a new box would be hard due to the significant trim surrounding it. Blown fuses haven't been a problem. The meter might have been changed by the power company but I have never changed the socket/meter box. They do look modern. I tried to insert a close-up of the meter but maybe I'm too new for posting pictures. The meter face plate says, from top to bottom:
Rf 13 8/9
the 5 spinning metering dials
200 CL form 2S Type MS
240v TA 30
3w Kh 7.2
Single stator watt hour meter 60 hz
Duncan Manufacturing

Probably the power company will come out and tell me if the meter and socket/box is ok for my plan. That will be one of my first steps.

Ironhand,

Fuses are not blowing
You’ve voiced my fear: That after committing hundreds of dollars in afcis, panel, etc that I'll have an arc fault somewhere. Then I am SOL with an outstanding permit. I don't want to depend on the good graces of an inspector to overlook a non AFCI breaker.

2 Are there ways for me to test for an arc fault on the existing circuits before I commit?

Allan J,

There is no room to install a new main breaker panel next to the old fuse box. Its in a stud cavity in a pantry wall that is only ~20" wide. The fuse box takes up the whole width between door and adjacent wall. I would rather just stay with the fuse box.

Regarding down time without power. I don’t see how thats gonna work for more than a 5 or 8 hours. The refer stops, no furnace, etc….. I’d have to work fast after the power company removes the meter to; pull the old fuse box, put in the new panel, hook it all up, then get the timing right for same day inspection and meter reinstall.

3 So what if it doesn’t pass, (those pesky AFCIs on K&T)? Then my wife will be really unhappy…… I’ve heard of “hot changeovers” but I don’t think the inspector would be happy with that because he would be looking at a live panel and would know.

Ray,

I can't see how I could fish wires in the ceilings for the lights. There are finished floors above and below. Walls wouldn't be too hard but on a 3 story 2500 square foot house its more work than I want. My wife is tired enough of a dusty gutted basement and laundry room.

Furd,

I hear you about Seattle. I really want to stick with my current service drop and meter box. A new mast and socket would make it more than a 4-8 hour change over..…..for me anyway. I don’t want to be without power for more than a work day. I want to do it by permit but that is my original question with the K&T vis a vis AFCI requirements.

Guys my next move after gathering as much info from your wisdom is to talk to the inspector to see if my plan will work. Last resort is to find an electrician and pay for a consultation, maybe even get an estimate to see if that makes sense.

4 Lastly, if a new panel is unworkable my follow-on question is can I just re-purpose one of the separate breaker boxes of the old 240v appliances to run a 6-3 mn to a new sub panel for my basement/future MIL apartment remodel? The basement was only on one K&T circuit and is about 25% of total floor area of the house.

Thank you again for your advice.

Eric
 
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Old 01-23-16, 03:29 PM
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A lot of the older houses in Seattle have the meter base and service conduit mounted under the siding. It makes for a neat installation but also makes upgrading a pain in the rear. Most upgrades use surface mounted meter bases with unistrut supports on the conduit and they look like crap. Service Entrance cable is not very common in Seattle although some installations do exist.

The reason for changing the conductors is that the insulation deteriorates. One job I did (in Seattle) was a three-phase 240/120 (tapped delta) line from an 80kVA transformer bank to a fuse panel. The wires as they left the conduit had many places where the insulation had literally fallen off. I thought that I could have blown on it and caused the wires to short circuit. I was absolutely scared s***less when I saw that but because of the load I couldn't de-energize it until I was ready to fix it. Needless to say, I got my tools and supplies and took care of it ASAP.

Eric, SCL does not approve the meter or anything else, that is the province of the city electrical inspector. SCL does specify what is needed and what can be used but they do not issue the permits nor do the inspections. Permits are issued through the Seattle Department of Construction & Inspections and here is their website. Seattle Department of Construction & Inspections Seattle does a reorganization about every five to seven years and I have no idea where this will lead you. After all your research you may decide that those fuses aren't so bad after all.

And, in case you are wondering, here are the requirements for service from SCL. Electric Service I haven't read these for at least twenty years so I am probably wrong on several points. I DO know that there is likely a fair amount of bureaucratic BS included. And if it seems as if I have a grudge against my former (40 + years ago) employer, I do, but not for anything that was related to my time there.

As for the add-on circuit breaker panels...it really depends upon how they are powered. I think, as a member with less than ten posts you do need to have pictures approved by a moderator before they post. You can always host your pictures on a hosting site such as photobucket.com or imgur.com and then post the public URLs here. Do not use tinypic as the forum rejects it.
 
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Old 01-23-16, 04:04 PM
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I do not know of a way to test if an existing circuit will work on an AFCI breaker. You could install an AFCI receptacle in line after the fuse and see if it works. They wire the same as a GFCI device with line and load terminals.

I recommend you contact the local electrical inspector and see if they require AFCI's on a service change. They may not.
 
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Old 01-24-16, 10:10 AM
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CasualJoe,

1 I’m curious why you say I should change the meter and socket. When you say socket do you mean just the guts in the box or the whole box?
Without knowing the age of the meter socket and with no pictures, I was assuming the socket could be as old as the panel which could be 75 years old. There is no way a meter socket and service entrance wiring of that age would be in re-useable condition. You later mentioned that:

The meter might have been changed by the power company but I have never changed the socket/meter box. They do look modern
Don't worry about the meter, the utility will always furnish and install the meter. It's the meter socket that is your responsibility. If it looks modern it may have already been changed.
 
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Old 01-25-16, 01:25 PM
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I'm going to call the inspector tomorrow to see if may plan is reasonable. Thanks all for your help. I'll let you know how it goes.
 
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Old 09-29-16, 09:01 AM
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So what was the outcome? Did you have to install ARC-Fault? did you get a new service yet?
 
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