Replacing knob and tube. Do i need to bring the house up to code?

[Pharon]

Consider this.

In most wood framed homes bringing the EGC into say the living room provides the other conductor needed to electrocute the occupant.

Very few people, even less home occupants will receive a line to line or line to neutral shock and an EGC will not prevent either of those types of shocks.

Most home occupants that get a shock will be shocked line to ground and if there is no ground to contact that possibility is illuminated.

Now of course, go into a room with metal plumbing and things change a bit.

I not really anti-EGC but I think it is wise to look at things from all perspectives and not just assume an EGC makes a room safer.


As far as K&T, they do not run side by side like a cable so even if you they are bare they will not short and are unlikely to cause a fire due to the ceramic knobs and tubes. Can we say that about how we run NM?

Overheat NM and it will either short or being directly against wood start a fire.

Again, I am not anti-NM just looking at things from all sides instead of assuming new is always better.

Fair points, iwire. I guess I'm considering the most likely scenario of a hot fault in a metal outlet box that has no ground to trip the breaker and instead energizes the box and the metal face plate. Or an appliance short that energizes the metal appliance housing because someone used a 3 to 2 prong adapter to fit in the outlet.

Or the most likely scenario with K&T, namely that it's highly unlikely that it's been unmodified over the decades and that there's a loose connection or mistake just waiting to expose itself when something brushes against it the wrong way.

Keep in mind, this is all just my opinion, which is probably heavily biased due to the fact that I live in a 125-year old home.

 

[edlee]

I am pretty sure the answer is a "no", but i have to ask anyway. I have a job i am bidding and the owner wants all the knob and tube ripped out and replaced. Those are always hard jobs to bid. But i started second guessing myself if i would be required to bring the house up to code as far as spacing goes and dedicated circuits in the kitchen? No outlets outside...stuff like that. What has been some of your guy's experience?

My experience over the years is that no inspector would make me put in additional outlets (lighting or power) if all I was doing was replacing the existing. Unless the walls are opened up of course.

As it is it can be a big expense just to disconnect and replace what's there, let alone add a bunch new outlets.

Usually though the homeowner ends up asking me for an additional outlet or two in a spot where they really need it.

good luck!

 

[don_resqcapt19]

I'm of the opinion that branch circuits with EGC's are always safer than those without. And I'll choose today's Romex insulation over 90 year old cloth K&T every day of the week, even if it's never been modified.

You can't drive a nail or screw between the two conductors of K&T like you can with NM. (this must happen a lot as it is one of the reasons we now have to use AFCIs:happyno