TrueWest wrote:


In order to answer your questions competently I'll need some information

from you first. Is the metal jacketed cable in your home Type AC

armored cable that has a metal bonding strip inside the jacket to assure
continuity or is it the older BX cable that has the spiral metal tape
jacket with no bonding strip?


I believe it's AC. It's old and it looks like it's just a spiral
strip.

Since there is no bonding strip inside the spiral metal tape jacket you
have two choices. If you want people protection you install a Ground
Fault Circuit Interrupter (GFCI) to protect the circuit. The best place
to install that is as a GFCI Breaker in the panel. I suggest that it be
installed in the panel that contains the Over Current Protective Device
because when a circuit goes dead you will check there as a matter of
course. If you use a receptacle type GFCI then when it opens you will
have to know were it is installed and remember that the circuit is
protected by a GFCI that is in another room. Finding which GFCI has
tripped when they are not in a panel is a pain. If you need a low
impedance Equipment Grounding Conductor (EGC) for operational reasons
other than for human safety then you will have to install one as
permitted by article 250.130 of the US NEC.

"250.130 Equipment Grounding Conductor Connections.
Equipment grounding conductor connections at the source of separately
derived systems shall be made in accordance with 250.30(A)(1). Equipment
grounding conductor connections at service equipment shall be made as
indicated in 250.130(A) or (B). For replacement of non–grounding-type
receptacles with grounding-type receptacles and for branch-circuit
extensions only in existing installations that do not have an equipment
grounding conductor in the branch circuit, connections shall be
permitted as indicated in 250.130(C).
(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions.
The equipment grounding conductor of a grounding-type receptacle or a
branch-circuit extension shall be permitted to be connected to any of
the following:
(1) Any accessible point on the grounding electrode system as described
in 250.50
(2) Any accessible point on the grounding electrode conductor
(3) The equipment grounding terminal bar within the enclosure where the
branch circuit for the receptacle or branch circuit originates
(4) For grounded systems, the grounded service conductor within the
service equipment enclosure

[Handbook commentary] Because of the requirements of 250.52(A)(1), an
interior metal water pipe more than 5 ft from the point of entrance of
the water pipe into the building is no longer allowed to serve as a
connection to the grounding electrode conductor. " copyright 2002
National Fire Protection Association.

You may well find it is more cost effective to run a new fully grounded
circuit to the particular equipment that you need to have grounded for
non human safety reasons than it is to run a separate EGC back to the
Service Equipment or to the Grounding Electrode System.
--
Tom H