home electric question

[stl]

Re: home electric question

I finally got down there to give it a closer look. It looks like there is a short run of old knob and tube that goes to that box behind the tv. Most of the knob and tube in the house has been replaced but they did not replace this not sure why. Now I am leaning toward running a new line, and just not use the plug with knob and tube.

 

[Beefer]

Re: home electric question

Yep, time to run a new line. Period.

 

[j_martin]

Re: home electric question

On the lightning protection side of this story. I work with ESD protection as part of my job, and have had extremely good success where others have flat failed, like with the network wiring in a campus of metal buildings, for instance.

Lightning is not only high voltage and current, it is also has extremely high frequency components. A lightning protector won't stop it unless all circuits going to the device (like antenna and power, for instance) go through the same lightning protector. The way the protector works is that for the millionth of a second the surge is there, it clamps everything together, (yes even the hot wire) and then lets go quickly when the surge is gone. The device, (TV) may actually jump several thousand volts from ground for a microsecond, but all inputs jump together, so there is not a high relative voltage between any two inputs, and the device is saved.

That was an attempt to describe the dynamics of an extreme energy radio frequency lightning strike and protection from it.

hope it helps, but not suprised if it doesn't
John

 

[Mark42]

Re: home electric question

I finally got down there to give it a closer look. It looks like there is a short run of old knob and tube that goes to that box behind the tv. Most of the knob and tube in the house has been replaced but they did not replace this not sure why. Now I am leaning toward running a new line, and just not use the plug with knob and tube.

Well, that explains it. Only saw knob and tube wire job once. It was an "upgrade" from gas lights in my friends house. They had it all rewired in the 70's. Not a minute too soon. They left the knob and tube wire in the attic just for show, but it was not connected.

Anyway, time to run a new circuit.

 

[stl]

Re: home electric question

Got The new line ran and up to the wall. Just have to get a box and outlet tomrrow and and wait for the electrician to hook it up to the main, then no worries. I knew there was some knob and tube still in the house when I bought it, but I was under impression that it was just the over head lights on the second story which is fine. I gave it a close look tonight and aside from the overhead lights, which I am not concerned about, this is the only knob and tube left. It is only a strech of a couple of feet , not sure why they left it. I am sure there is a good reason. Thats why I am just gonna leave it alone and not use that outlet anymore. Thanks for all of your expertise.

 

[rwise]

Re: home electric question

Do not attempt this approach. A lamp plugged into the outlet will give you induced voltage across the ground terminal. Not good.

What maybe .001 volt?
Still not correct new circuit is best,,, but it works!

 

[levittownnick]

Re: home electric question

Lets see, at the plug
1 Hot wire (Black)
1 neutral wire (white)
1 ground wire (Bare or green)

at the load center
1 Hot wire (output of circuit breaker) (black wire)
1 neutral/ground bar (white wire and bare/green wire)

so one could have a ground (though not correct) by jumping the ground terminal (green) to the white terminal at the new 3 pin outlet, again not considered correct,,,,
but cheep and easy

I'm not trying to be a smart *** but the above quote is a terrible idea for the following reason: People have been killed (Fact not fiction.)
It is common for the white wire to be "Hot" by getting crossed (transposed) with the black wire or where a two-wire cable is used, for a switched leg, the white wire WILL be "Hot". In a situation that I am aware of, the white wire was used as in the above quote, and a drill with a 3-wire cord connected to a GFCI outlet. The operator of the drill was electrocuted. He was the father of young children. The GFCI couldn't save him because the path was through what should have been the ground wire. The ground wire is not protected by the GFCI nor can it be. Tragic.

 

[j_martin]

Re: home electric question

Back about 1970, Jordan MN got flooded. Near the river are many old factories and warehouses. They all got flooded.

Those that had modernized and put in conduit all had to be rewired.

Those that still had the knob and tube systems got new fuses and they were up and running.

Amazing, isn't it.

John

 

[SS MAYFLOAT]

Re: home electric question

I'm not trying to be a smart *** but the above quote is a terrible idea for the following reason: People have been killed (Fact not fiction.)
It is common for the white wire to be "Hot" by getting crossed (transposed) with the black wire or where a two-wire cable is used, for a switched leg, the white wire WILL be "Hot". In a situation that I am aware of, the white wire was used as in the above quote, and a drill with a 3-wire cord connected to a GFCI outlet. The operator of the drill was electrocuted. He was the father of young children. The GFCI couldn't save him because the path was through what should have been the ground wire. The ground wire is not protected by the GFCI nor can it be. Tragic.

I know of a very similar accident. Milton Florida 1979, a garage owners son told his dad that the drill was giving him a shock. The dad picked up the 1/2 metal cased drill and proceeded to get electrocuted (which means fatal/dead). The ground prong was cut off. A ground is a very important feature, especially with uninsulated tools. Many deaths from electrocution is due to the old metal cased tools. Probably why you don't see many on the market anymore.

 

[stl]

Re: home electric question

Pull off the outlet cover and inspect what is there. I bet it is a metal box with metal sheathed cable (BX). If so, then the box should be grounded via the BX cable. A simple neon bulb tester will determine this by placing one end of the tester in the outlet (the large blade, I think, should be the load) and the other to the metal box. If the tester lights up, then you have a grounded circuit. Turn off the breaker to the box, replace the outlet with a new outlet with ground and attach the ground screw on the outlet to a screw on the metal box with a length of bare copper wire. This will provide a grounded outlet that meets code.

Note: do not use the screws that mount the outlet to the box to attach the copper ground wire. It will work, but won't meet code. You may have to use a sheet metal screw to attach the copper wire to one of the holes in the back of the box.

After looking I noticed that two other non grounded outlets in the living room do have the metal sheathed cable. The metal cable does not go all the way back to the fuse panel. both of them lead to a junction box that is fed by a silver looking wire that has Norax NM printed on it. Can I still ground these outlets using the method mentioned above.

 

[rwise]

Re: home electric question

I'm not trying to be a smart *** but the above quote is a terrible idea for the following reason: People have been killed (Fact not fiction.)
It is common for the white wire to be "Hot" by getting crossed (transposed) with the black wire or where a two-wire cable is used, for a switched leg, the white wire WILL be "Hot". In a situation that I am aware of, the white wire was used as in the above quote, and a drill with a 3-wire cord connected to a GFCI outlet. The operator of the drill was electrocuted. He was the father of young children. The GFCI couldn't save him because the path was through what should have been the ground wire. The ground wire is not protected by the GFCI nor can it be. Tragic.

Yes that is tragic, the white wire should never be used as a hot, it gets folks killed!
Also the ground pin should never be remove, and polarized plugs should not be trimmed to *fit*

 

[levittownnick]

Re: home electric question

Yes that is tragic, the white wire should never be used as a hot, it gets folks killed!
Also the ground pin should never be remove, and polarized plugs should not be trimmed to *fit*

There are several instances where the "code" permits the white wire to be used as a HOT lead.
There is never a reason to use the green or bare wire for other than ground.

 

[Mark42]

Re: home electric question

After looking I noticed that two other non grounded outlets in the living room do have the metal sheathed cable. The metal cable does not go all the way back to the fuse panel. both of them lead to a junction box that is fed by a silver looking wire that has Norax NM printed on it. Can I still ground these outlets using the method mentioned above.

If you jump the hot side of the outlet to the metal box with a tester and it lighs, yes, you can put in a grounded outlet and ground wire to box. If you open the junction box, you should be able to see if the silver sheathed cable has a ground or not.

Norax is the brand. NM means "Non-Metalic" cable, in other words, it does not have the metal sheathing. Most likely it has a ground wire inside.

 

[Mark42]

Re: home electric question

There are several instances where the "code" permits the white wire to be used as a HOT lead.
There is never a reason to use the green or bare wire for other than ground.

That is true, but it also states that the wire should be recolored black with tape or marker to indicate it is a hot lead. Common in 3 and 4 way switched circuits.