Using a ground as a neutral

[Ronald Blue]

K&T was originally insulated, but with time and critter help the insulation falls off. All the K&T I have encountered has been 14 gauge wire. It is not a good idea to leave it in place. My sister owned a house that supposedly had all the K&T replaced. What we found was the easily accessible wiring was replaced, but wiring in the walls was still K&T. They even pig tailed new outlets on romex that was tied into K&T behind the outlet box. Some was on 20 amp breakers. My Dad and I ran new runs to avoid the patch work and pulled out what was done wrong that we could reach.

I definitely remember when there was insulation on overhead powerlines. As you say over time the elements and critters took care of it. To add to that there used to be a factory near me and it was called "porcelain" that made all sorts of insulators for power transmission. In the later years it was owned by McGraw Edison and then became Cooper Power Systems. They made some pretty large insulators as I recall.

[Andrew More]

K&T was originally insulated, but with time and critter help the insulation falls off. All the K&T I have encountered has been 14 gauge wire. It is not a good idea to leave it in place.

I honestly think this depends on the wire. Like to much about old houses there are things that are fine, since the house keeps out the weather, and things that are not. The insulation on the wires in my 100 year old house was all fine, but obviously YMMV. Even if it gets worn bare the rest of the system is setup to handle this. I'm not sure what the degradation of romex is going to be in 100 years. In theory it's going to be fine, since it's plastic, and plastics never die, but we'll see.

The issue with removing it is that most things are fine until somebody messes with them, and then there are problems. I'd love to see some stats on how often electrical problems are caused by people changing things vs other types of problems, like things degrading over time.

The other big issue is that I do NOT believe you can get insurance for a house where you admit to having K&T. If you just don't ask, don't tell, you can usually get insurance, but if you say "I know it's got some Knob and Tube" they'll refuse to insure. At least that was my experience a couple of years ago calling around to just about every insurance company I could get ahold of. Which is interesting, because I know the town I live in has to have a large amount of K&T (oh and usually few fires).

I'm wondering if some insurance agencies aren't planning to collect the fees and then to refuse to pay citing K&T wiring. You just don't know.

Which is why I've removed all of mine.

[Brian Elfert]

Your breaker could be tripping because it's a GFCI or AFCI. Both are far more sensitive than older breakers, and they've started requiring them in modern panels.

I believe it is a standard breaker as my memory is that AFCI was not required for bathroom receptacle circuits under the 2014 NEC. It has only tripped the one time since I installed the circuit in 2014.

[Brian Elfert]

I have 40 year old NM (Romex) cable pulled out of my house that the insulation and wire still seems just fine. I scrap most of it because it is NM not NM-B. The removed lengths are not all that long so it makes sense just to spend a few bucks on new NM-B cable.

[Rollie Meyers]

And that's an exception that never should have been allowed. I'd love to hear a good reason why it was, but I don't think one exists.

Have heard it was a wartime effort to save wire, the exception allowing it should have been removed decades prior to the 1996 NEC where it finally changed.

Houses did not have a ground wire up until the 1960's. There is no good way to run a ground to an existing outlet clear from the panel. It was probably safer to use the neutral then to have no ground at all. I do not think you are allowed to tie a ground wire to the metal gas pipe on a stove?
Bill D

Absolutely not permitted to ground through a gas line, metallic gas piping is bonded to the metallic water lines, while I don't know how other utilities do it, PG&E does have a nonmetallic bushing to electrically isolate the customers lines from theirs, may not be as important in the future as the metal UG lines are replaced with nonmetallic piping.

[Jerry Bruette]

Absolutely not permitted to ground through a gas line, metallic gas piping is bonded to the metallic water lines, while I don't know how other utilities do it, PG&E does have a nonmetallic bushing to electrically isolate the customers lines from theirs, may not be as important in the future as the metal UG lines are replaced with nonmetallic piping.

When our house was built I questioned the ground wire on the gas line because I knew the line that was feeding the meter was plastic. I was told that the ground wire was to ground the metal gas lines in my house to the panel, in case they somehow came in contact with a live wire. It made sense to me.

[Wade Lippman]

I read 7 milliamps can stop the heart. It may or may not restart. A GFCI must trip at 5 milliamps or less.
Bill D.

Then I guess I am lucky to only have 0.6ma. A neighbor had a ammeter capable of measuring it. Only 8 times stronger and it would trip a GFCI!

[Frank Pratt]

One problem of the neutral wire is it can have a voltage different than the ground.

Even though at some point the ground and neutral are bonded the distance from ground, an imbalanced load and the distance to the bond to ground can add up to an uncomfortable if not dangerous situation if one happens to be touching a stove while turning on the water.

jtk

The fact that you felt any tingle at all should have warned you that the idea was stupid and dangerous. You sir, should not be playing around with electricity.

[Andrew Pitonyak]

Houses did not have a ground wire up until the 1960's. There is no good way to run a ground to an existing outlet clear from the panel. It was probably safer to use the neutral then to have no ground at all. I do not think you are allowed to tie a ground wire to the metal gas pipe on a stove?
Bill D

I was visiting a friend in the early 90's and he mentioned that he had paid an electrician to install some three prong outlets since his house had only two prong. He then told me what he paid and I said "he did not run a ground" and my friend insisted that the electrician had. I opened up an outlet and sure enough, the electrician had simply tied neutral to the ground in the outlet.

[Frank Pratt]

I was visiting a friend in the early 90's and he mentioned that he had paid an electrician to install some three prong outlets since his house had only two prong. He then told me what he paid and I said "he did not run a ground" and my friend insisted that the electrician had. I opened up an outlet and sure enough, the electrician had simply tied neutral to the ground in the outlet.

Yikes! Was that a real electrician or one of those home handy person types? I sincerely hope your friend either got his money back or had the "electrician" correct his mistake.

I Canada code requires that the circuit be put on a GFCI on an ungrounded circuit if old 2 prong receptacles are replaced with 3 prong.

[Maurice Mcmurry]

I have worked on several old knob and tube wired houses in town that were upgraded with 3 prong grounded receptacles with the neutral daisy chained to the ground. It is a technique some old-timers embraced for a while. I was asked to see about removing a window AC from a 2nd story window that had a history of shocking people. It was plugged into one of these "upgraded" plugs that had reverse polarity. The steel case had 120 volts to ground. A siding guy had been shocked and was not happy.

[Jim Koepke]

It was plugged into one of these "upgraded" plugs that had reverse polarity.

Probably not many here who remember or even know about the AC/DC radios that were common into the 1960s. They were usually five tubes with filaments wired in series so they didn't need a transformer. Usually the plugs were unpolarized. If reception was poor flipping the plug would often clear it up. One side of the cord was grounded to the chassis. One could get a nasty sting from one of these missing a knob if it was plugged in with the hot side of the line going to the chassis.

jtk

[Charlie Velasquez]

Yikes! Was that a real electrician or one of those home handy person types? I sincerely hope your friend either got his money back or had the "electrician" correct his mistake.

I Canada code requires that the circuit be put on a GFCI on an ungrounded circuit if old 2 prong receptacles are replaced with 3 prong.

Also, here. It must also be labeled as “GROUND FAULTED, NOT GROUNDED” and no ground wire is allowed if you add additional 3-prong receptacles downstream (and every downstream receptacle must also be labeled as ground faulted, not grounded).