Knob and Tubing ?

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precise8128

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Memphis, TN
So you go to a service call lights and receptacles are not work, the customer has a fused panel. As a electrical contractor what do you offer to repair it, replace it and upgrade, or walk away.

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So you go to a service call lights and receptacles are not work, the customer has a fused panel. As a electrical contractor what do you offer to repair it, replace it and upgrade, or walk away.


Sure they have lights and receptacles not working but what is the problem? Blown fuse are what?

There is nothing wrong with a fuse panel if it's in good shape with the correct fuses.

It really depends on what the customer is interested in having done and the condition of the electrical system (is it safe).
 
So you go to a service call lights and receptacles are not work, the customer has a fused panel. As a electrical contractor what do you offer to repair it, replace it and upgrade, or walk away.

As an electrical contractor, I approach K&T installations as my bread and butter. I have spent decades working on K&T, from simple device replacement to total K&T demo and replacement.

Are you new to K&T? If so, there is plenty to learn, not the least of which are the rules written in today's NEC that still apply directly to K&T, either concealed behind the finished surface, or exposed. The NEC rules are not just in the Knob and Tube Article at the end of Chapter Three, but are scattered about elsewhere, also.

You may also have local ordinance that apply to existing electrical installations that define original fused 20 and 30 Amp Electrical Services. In my area, there is a history of those old 20 and 30 Amp Services being defined as "overloaded", making it a violation to add new branch circuits. However, the maintenance of the existing branch circuits and devices is perfectly OK.

You can create a lot of customer-good-will by finding the simple failed connection or blown fusestat for a modest fee, 'cause, you can bet, the customer is scared of you saying the whole thing has to be replaced. As Growler and K8MHZ ask, what is the condition of the wiring system?
 
Pretty shabby they had other electricians out and just alot of unsafe work. I can admit I dont have alot of knob and tube experience, by any chance do you know of any good study resources, or is it all hard knocks, trail and error out in the field hands on training?

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If I am adding a circuit I just move on and do my job. I guess if I wanted more work it would be worth trying to sell but that K&T can be a mess esp in a 2 story home
 
. . . do you know of any good study resources, or is it all hard knocks, trail and error out in the field hands on training?

After exhausting the content of The American Electrician's Handbook, the next best learning I got was from all the demo of existing K&T that I happened to get with a long string of residential kitchen gut and resets. I got involved with the demo, especially if the original panel, or it's shell with backfed K&T branch circuits, was present, and then paid attention to how each of those was assembled.

Later, online discussion on the Forums helped augment my understanding by disabusing me of my incorrect use of terms and concepts, as well as wrangling the actual applicable Code passages.

Just repairing and maintaining existing bits (when practical and safe), along with restoring hacks of the less knowledgeable has provided plenty of work.
 
After exhausting the content of The American Electrician's Handbook, the next best learning I got was from all the demo of existing K&T that I happened to get with a long string of residential kitchen gut and resets. I got involved with the demo, especially if the original panel, or it's shell with backfed K&T branch circuits, was present, and then paid attention to how each of those was assembled.

Later, online discussion on the Forums helped augment my understanding by disabusing me of my incorrect use of terms and concepts, as well as wrangling the actual applicable Code passages.

Just repairing and maintaining existing bits (when practical and safe), along with restoring hacks of the less knowledgeable has provided plenty of work.
yeah you learn alot of good sruff on here, Thanks

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So you go to a service call lights and receptacles are not work, the customer has a fused panel. As a electrical contractor what do you offer to repair it, replace it and upgrade, or walk away.

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We'll ask them to check with their homeowners insurance , as most will insist their coverage does not cover fused panels , or K&T for that matter

~RJ~
 
There are not many fused panels or K&T wiring here (which dont necessarily go hand in hand). Replacing the panel is usually not going to solve a fuse panel problem as the branch circuits are often overloaded. Lights and receptacles not working is a troubleshooting issue and having experience and using a systematic approach based on that experience is imho the best and fastest way to solve those issues. You'll probably lose your ass on a few of those kinds of calls, however it is quite satisfying to me to figure out solutions to those problems.
 
The problem with old fuse panels tends to be they just don't have the capacity for what's needed.
As far as panel amperage, conductor space, 120v circuits, and 2 or 3 pole circuits.
So what most likely started as a clean code complaint install may have been turned in to a violation pic of the month by people in the past adding more circuits.

The S-fuses required 11/1941 were called "tamper resistant" in that only a fuse of that amperage would fit (up to 15a, 16-20a, 21-30a).
Replacing the Edison based fuse 1 size fits all (15a, 20a, 25a, 30a, & light bulb).
Also by design a penny behind the fuse trick does not work. Because the load side of the fuse was no longer the threads, it was the underside front lip / shoulder.

Fuse panels have no means of GFCI or ark fault protection. So sometimes you see upgrades that should have been protected with GFI or AF but were not. Just seen on fuse panel the other week. Had air conditioning, in-ground pool equipment, pool light, outside receptacles, and maybe something else added. Nothing was GFI protected. Lots of double tapes and the A/C run off line side feed through lugs. So if you pulled the main, the A/C fused disco would still be powered. Not to mention all the 2 wire NM wire feeding the branch circuits.

Plus the fuse panel locations may no longer be acceptable.

Knop-and-tube was a wiring method developed because the original wire insulation was not very good. The conductors had to keep a minimum of 2.5" apart and be insulated where passing thru wood to prevent leakage. But Knob-and tube was on it's way out in the 1930's in favor of easier Romex and BX. No longer permitted for new installs by the mid 1970's.

I can't tell you when the last distribution fuse panels were installed. Defiantly still done in the 1970's. Chicago used to require S-type panel boards for emergency circuits. It's still an option. I remember seeing probably 42 circuit fuse panels on what looked like a new install in the downtown. Was told the idea was for emergency circuits they could limit anyone from turning it back on by using fuses. Can't think of anywhere it's prohibited in the NEC except you would need to AF & GFI protect another way. Don't know if you can still buy a new fuse panel board. Except there are new old stock ones on Ebay. Imagine if you put 200 amp fuse panel on you bid. Buy a new one on Ebay and mount it. Tell them a circuit breaker panel is an extra.

They really just got a bad rep with insurance companies and home inspectors.
 
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