Working with Knobs and Tubes Electrical Installations

"W. Watson" wrote:
The sand is certainly an interesting angle from the stand point of
conductivity. When I go down there, I will check with nearby neighbors,
electrical contractors/suppliers and the city engineers to understand what
we might be up against.

Another interesting angle on all this was brought up by another poster, or a
web site I visited was KnT fixtures may be disappearing. If so, that could
spell doom for many of the inhabitants of SF and elsewhere around the
country who might need to replace them.
Click to expand...

It hasn't been legal to repair Knob and Tube in a long time. The
only place it was legal for repairs or new work was in barns and similar
outbuildings.

BTW, round 'Romex' will usually pass through the hole after the tubes
are pulled out.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
On 9/24/07 1:51 PM, in article 46F82348.BE434762@earthlink.net, "Michael A.
Terrell" <mike.terrell@earthlink.net> wrote:

"W. Watson" wrote:

It's certainly easy enough to run a third wire to a pipe. At worst, I can
drive copper pipe into the ground outside the house and bring it in where
needed.


It doesn't meet code, either.
Click to expand...
As I recall, without going for the Code book, it requires a zinc rod.
 
Don Bowey wrote:
On 9/24/07 1:51 PM, in article 46F82348.BE434762@earthlink.net, "Michael A.
Terrell" <mike.terrell@earthlink.net> wrote:

"W. Watson" wrote:

It's certainly easy enough to run a third wire to a pipe. At worst, I can
drive copper pipe into the ground outside the house and bring it in where
needed.


It doesn't meet code, either.


As I recall, without going for the Code book, it requires a zinc rod.
Click to expand...

Or copper plated steel. It depends on the soil.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
Thanks for the tip on the round romex. In my community in the foothills of
the Sierra, it seems to be done somewhat often. I happened on a buddy who is
a contractor here, and he gave me several tips on how to repair portions.
See my next post.

Michael A. Terrell wrote:
"W. Watson" wrote:
The sand is certainly an interesting angle from the stand point of
conductivity. When I go down there, I will check with nearby neighbors,
electrical contractors/suppliers and the city engineers to understand what
we might be up against.

Another interesting angle on all this was brought up by another poster, or a
web site I visited was KnT fixtures may be disappearing. If so, that could
spell doom for many of the inhabitants of SF and elsewhere around the
country who might need to replace them.


It hasn't been legal to repair Knob and Tube in a long time. The
only place it was legal for repairs or new work was in barns and similar
outbuildings.

BTW, round 'Romex' will usually pass through the hole after the tubes
are pulled out.
Click to expand...
--
Wayne Watson (Nevada City, CA)

Web Page: <speckledwithStars.net>
 
Two things occurred yesterday that'll impact my story. I ran into a
contractor buddy who has dealt with KnT here in our small community in the
Sierra foothills. He's done this work before, and gave me some useful tips.
More importantly, I finally got to talk to my son about this. His first
message was through my wife. Ahem! He's not expecting me to rewire the whole
place. What he's doing is re-modeling the kitchen, and wants two outlets
moved, and possibly a new one put in.

My buddy, aside from providing some electrical hints, suggested if lots of
work is needed to find someone here that does such work, and hire them to go
to SF to do the work. The building market is suffering, and contractors are
looking for work where they can get it. They can probably get good money in
SF for more than here, but less than a SF contractor. We are 150 miles from SF.

In any case, I found two people here that are experienced in KnT. They
probably won't be needed now that the focus of this effort has been
substantially narrowed. I'll talk to them anyway.

Don Bowey wrote:
On 9/23/07 11:48 AM, in article fd8qhu$4a0$1@eskinews.eskimo.com, "Mark
Zenier" <mzenier@eskimo.com> wrote:

In article <uDrJi.51469$Um6.9584@newssvr12.news.prodigy.net>,
W. Watson <wolf_tracks@invalid.com> wrote:

I would think if installed a 6' copper ground bar into the soil outside his
house, and use 3-prong outlets where the ground wire is to the copper pole,
that it would pass code.
If SF is like Seattle, if you don't have a ground rod
the power panel ground is bonded to your water line.

You'll need to run the ground from the rod to your power panel where it
is hooked to the neutral line in the power drop. Otherwise you're
relying on the random condutivity between the safety ground and the
neutral to blow the fuse if case of a fault. You could end up with
stuff live because it didn't blow, or random parts of your house heating
up from the stray current.

Also if this is a subpanel off of another box..., well, hire a pro.

(I am not a Lawyer or an Electrician).


Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)



The US Code calls for a ground rod tie (length specified) in addition to
being tied to the power Co, neutral and ground.
Click to expand...
--
Wayne Watson (Nevada City, CA)

Web Page: <speckledwithStars.net>
 
In article <C31D3CBE.783B4%dbowey@comcast.net>,
Don Bowey <dbowey@comcast.net> wrote:
On 9/23/07 11:48 AM, in article fd8qhu$4a0$1@eskinews.eskimo.com, "Mark
Zenier" <mzenier@eskimo.com> wrote:

In article <uDrJi.51469$Um6.9584@newssvr12.news.prodigy.net>,
W. Watson <wolf_tracks@invalid.com> wrote:

I would think if installed a 6' copper ground bar into the soil outside his
house, and use 3-prong outlets where the ground wire is to the copper pole,
that it would pass code.

If SF is like Seattle, if you don't have a ground rod
the power panel ground is bonded to your water line.

You'll need to run the ground from the rod to your power panel where it
is hooked to the neutral line in the power drop. Otherwise you're
relying on the random condutivity between the safety ground and the
neutral to blow the fuse if case of a fault. You could end up with
stuff live because it didn't blow, or random parts of your house heating
up from the stray current.

Also if this is a subpanel off of another box..., well, hire a pro.

(I am not a Lawyer or an Electrician).


Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)



The US Code calls for a ground rod tie (length specified) in addition to
being tied to the power Co, neutral and ground.
Click to expand...
I'm talking about old practice, not current code. The code changes.
For example, they didn't use plastic pipe in the old days.

The second point is that using a seperate ground and just running that
to some outlets is a serious safety hazard.

Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)
 
W. Watson wrote:
My son lives in San Francisco, and would like me to re-wire some of his
house. It's pretty old and he says it has knobs and tubes wiring. What
is that, and how difficult would it be to replace whatever is there with
current outlets, and maybe upgrade his entire electrical service?
Click to expand...
Knob and tube wiring, if it has not been abused, is not automatically
dangerous. Splices are twisted and taped, but they are also soldered. I
have seen only one K&T splice fail (it was a ‘cold’ solder joint from
the start). If the wiring has been properly fused, current is no more
problem than it is for any other type of wiring. See also the last point
below.

There certainly are some virtues in replacing it, but entirely replacing
K&T wiring is *very* expensive.

As ehsjr said, one code acceptable method is using GFCI protection for
grounding type outlets (could just be a GFCI outlet). The outlet has to
be marked as Ed details.

A ‘ground’ wire may be added and a grounded outlet installed. For this
purpose, the ‘ground’ wire does not have to be routed with the other wires.

In the past the added ‘ground’ wire could be connected to a metal water
pipe. That is no longer permitted. They now have to be connected to
anywhere on the ‘grounding electrode system’, which includes the panel
ground bar, the heavy conductors to the grounding electrodes, the first
5 ft of water pipe inside the building if the water pipe is used as a
grounding electrode (the service connection to the pipe should then be
in the same 5 ft.).

Water pipe, at least 10 ft buried, has been required to be used as a
grounding electrode for a very long time. More recently, because water
service pipe can be replaced with copper, a “supplemental” electrode has
been required. A ground rod is the easiest to install. A municipal metal
water system will have a much lower resistance to earth than a rod. The
code does not require old systems to add a rod unless ‘additional’ work
is done. The code now usually requires an additional “concrete encased
electrode” for new construction.

‘Ground’ wires are not allowed to be attached only to isolated ground
rods. As Mark said, this is a major safety hazard. Assume your metal
case ‘grounded’ drill develops a short from hot to case. The ground
current flows to the ground rod. Further assume the ground rod is not
only the code acceptable 25 ohms (with 2 rods it can be any resistance)
by a very good 12 ohms. There is 10 amps added. Depending on the other
load on the circuit, the fuse/breaker will open in a little while to
never. In the meantime you are connected to the hot wire holding the drill.

A major function of the ‘ground’ wire is to cause a high current to flow
on a short to open the fuse/breaker. The path is ‘ground’ wire to
service panel, through the required neutral-ground bond, and through the
service neutral to the supply transformer. Earth is not permitted to be
a part of the path.

Some insurance companies in some areas do not insure houses with K&T wiring.
Phil Munro posted 2 links on the subject:
http://www.waptac.org/sp.asp?id=7190
is a report to the Illinois Department of Commerce and Community Affairs
on adding building insulation around existing K&T wiring. No record of
hazard was found in the large number of K&T installations that had
insulation added around them.
The second link appears to no longer be online - was the record of a
complaint to the Maine state Bureau of Insurance by a homeowner against
an insurance company. The insurance company denied renewal of a policy
based on K&T wiring. The insurance company was ordered to renew the
policy because the insurance company "provided no justification for its
position that knob and tube wiring per se automatically provides grounds
for nonrenewal".

---
bud--
 
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