Hi all,

I have a detached garage that the former owner built and wired. He
ran 12 gauge (it might be 10) romex 2 conductor + ground through a
pvp pipe underground (about 60 feet) to the garage. At the source it's
double lugged to a 220 60 amp breaker (servicing the dryer) with the
bare ground wire acting as neutral, at the garage it's split (using
wire nuts) into two 120 circuits in a junction box at the garage.

I since added a panel at the garage end, back feeding the input line
to a 30 amp double pole breaker then distributed to four 120 v garage
circuits (2 for outlets and 2 for lights) via 15 amp breakers.

The service (source) end junction box I'm talking about only handles
220. There are six 60 amp breakers in this box, servicing the dryer,
a/c, heater, stove, water heater, and the house panel.

In the house the neutral and ground are connected via a metal bar.

When adding the junction box in the garage, as I untangled the 'rats
nest' that was his original connections, I saw that he had twisted
together all the ground wires from the receptacles and lights but they
did not actually connect to anything except each other.

Wanting the ground plug to be connected to a ground, I did some
research and found that normally a 4th ground wire would be run from
the service panel to the remote building, but I had only three wires,
two hot and one neutral. Research revealed that if the remote
building had no other metallic connection to the main site, that is no
phone, water, cable, nothing, then it was acceptable to drive a ground
rod at the remote building and to bind the netural and the ground
(assuming local code required ground and netural bond).

My detached garage meets this requirement, so I dorve an 8 foot ground
rod and attached it with heavy gauge copper wire to the netural of the
incoming feed at the panel in the garage.

Now when I put a 12 amp load on the garage circuit (a window a/c unit
+ lights) I measure 3 amps at the ground rod.

So 3 amps of the 12 amps (25%) is returning to ground through the
ground rod instead of the neutral wire.

My question is this:

Why am I seeing current at the ground rod?

How concerned should I be?

Keep in mind this circuit operation for 15 years with no problems
before I installed the panel or the ground rod.

Is the reason because the neutral wire is not of sufficient gauge to
carry the current back the 60 feet to the main panel and back to the
neutral coming from the electric company?

This made me think further about the ground rod of the house. Forget
the garage, in a normal home wiring setup when electric code mandates
the ground and neutral be bond at the service panel, I would expect to
see current flowing through the ground rod as well. My reasoning is
that the current has to return through the neutral (assuming no fault
in the circuit) and when it arrives at the service panel it has a
choice of returning through the electric company neutral or the
ground. Electricity will flow through the path of least resistance,
and logically I think the ground rod would offer the least resistance
- the wire length is shorter to the ground rod than to the transformer
on the pole.

However when I measure the current on the house ground rod it is zero.

Why is this? How is it that all the house current will flow to the
pole neutral and none to the ground?

Could someone please educate me on what I am missing here?

I know the ground rod is a safety backup for the electric company
neutral, and ideally would not carry any current, but I don't
understand why, when they are bound at the service panel, the ground
rod would not have at least some current like I'm seeing in my garage
setup.

Thanks.

"kpg" wrote in message
...
Hi all,

I have a detached garage that the former owner built and wired. He
ran 12 gauge (it might be 10) romex 2 conductor + ground through a
pvp pipe underground (about 60 feet) to the garage. At the source it's
double lugged to a 220 60 amp breaker (servicing the dryer) with the
bare ground wire acting as neutral, at the garage it's split (using
wire nuts) into two 120 circuits in a junction box at the garage.

I since added a panel at the garage end, back feeding the input line
to a 30 amp double pole breaker then distributed to four 120 v garage
circuits (2 for outlets and 2 for lights) via 15 amp breakers.

The service (source) end junction box I'm talking about only handles
220. There are six 60 amp breakers in this box, servicing the dryer,
a/c, heater, stove, water heater, and the house panel.

In the house the neutral and ground are connected via a metal bar.

When adding the junction box in the garage, as I untangled the 'rats
nest' that was his original connections, I saw that he had twisted
together all the ground wires from the receptacles and lights but they
did not actually connect to anything except each other.

Wanting the ground plug to be connected to a ground, I did some
research and found that normally a 4th ground wire would be run from
the service panel to the remote building, but I had only three wires,
two hot and one neutral. Research revealed that if the remote
building had no other metallic connection to the main site, that is no
phone, water, cable, nothing, then it was acceptable to drive a ground
rod at the remote building and to bind the netural and the ground
(assuming local code required ground and netural bond).

My detached garage meets this requirement, so I dorve an 8 foot ground
rod and attached it with heavy gauge copper wire to the netural of the
incoming feed at the panel in the garage.

Now when I put a 12 amp load on the garage circuit (a window a/c unit
+ lights) I measure 3 amps at the ground rod.

So 3 amps of the 12 amps (25%) is returning to ground through the
ground rod instead of the neutral wire.

My question is this:

Why am I seeing current at the ground rod?

How concerned should I be?

Keep in mind this circuit operation for 15 years with no problems
before I installed the panel or the ground rod.

Is the reason because the neutral wire is not of sufficient gauge to
carry the current back the 60 feet to the main panel and back to the
neutral coming from the electric company?

This made me think further about the ground rod of the house. Forget
the garage, in a normal home wiring setup when electric code mandates
the ground and neutral be bond at the service panel, I would expect to
see current flowing through the ground rod as well. My reasoning is
that the current has to return through the neutral (assuming no fault
in the circuit) and when it arrives at the service panel it has a
choice of returning through the electric company neutral or the
ground. Electricity will flow through the path of least resistance,
and logically I think the ground rod would offer the least resistance
- the wire length is shorter to the ground rod than to the transformer
on the pole.

However when I measure the current on the house ground rod it is zero.

Why is this? How is it that all the house current will flow to the
pole neutral and none to the ground?

Could someone please educate me on what I am missing here?

I know the ground rod is a safety backup for the electric company
neutral, and ideally would not carry any current, but I don't
understand why, when they are bound at the service panel, the ground
rod would not have at least some current like I'm seeing in my garage
setup.

Thanks


It sounds as though your wiring is in complete violation of the National
Electrical Code. #12 wire is rated for 20 amps and should have a 20 amp
circuit breaker protecting it. The three wire plus a ground rod set up for
a detached building is no longer permissible under the 2008 code. You need
the four wires. Using the bare wire in the cable as a neutral is not
allowed. You are seeing current on the ground rod because you do not have a
good neutral connection. The ground and neutral must be separate at a
subpanel. That connection together is only made at the main panel or the
meter. Romex is not approved to be used underground even though it is in a
pipe. You need to use conductors such as THWN or type UF cable in your PVC
pipe. You are not seeing any current on the ground rod connected to your
main panel (Assuming it is connected properly) because you have a low
resistance neutral conductor to carry the current back to the transformer.

"John Grabowski" wrote in
:

It sounds as though your wiring is in complete violation of the
National Electrical Code. #12 wire is rated for 20 amps and should
have a 20 amp circuit breaker protecting it. The three wire plus a
ground rod set up for a detached building is no longer permissible
under the 2008 code. You need the four wires. Using the bare wire in
the cable as a neutral is not allowed. You are seeing current on the
ground rod because you do not have a good neutral connection. The
ground and neutral must be separate at a subpanel. That connection
together is only made at the main panel or the meter. Romex is not
approved to be used underground even though it is in a pipe. You need
to use conductors such as THWN or type UF cable in your PVC pipe. You
are not seeing any current on the ground rod connected to your main
panel (Assuming it is connected properly) because you have a low
resistance neutral conductor to carry the current back to the
transformer.


Well, yes. That all sounds correct. Thanks.

So if one has an older detached garage with only 3 wires running is it
safe? It has been this way since 1942....

I wanted to replace the fuse panel with a breaker box and was going to
add a ground wire near the garage - I guess this is not good to do.


kpg wrote:
"John Grabowski" wrote in
:

It sounds as though your wiring is in complete violation of the
National Electrical Code. #12 wire is rated for 20 amps and should
have a 20 amp circuit breaker protecting it. The three wire plus a
ground rod set up for a detached building is no longer permissible
under the 2008 code. You need the four wires. Using the bare wire in
the cable as a neutral is not allowed. You are seeing current on the
ground rod because you do not have a good neutral connection. The
ground and neutral must be separate at a subpanel. That connection
together is only made at the main panel or the meter. Romex is not
approved to be used underground even though it is in a pipe. You need
to use conductors such as THWN or type UF cable in your PVC pipe. You
are not seeing any current on the ground rod connected to your main
panel (Assuming it is connected properly) because you have a low
resistance neutral conductor to carry the current back to the
transformer.


Well, yes. That all sounds correct. Thanks.

The dude wrote:

kpg wrote:
"John Grabowski" wrote in
:
It sounds as though your wiring is in complete violation of the
National Electrical Code. #12 wire is rated for 20 amps and
should have a 20 amp circuit breaker protecting it. The three
wire plus a ground rod set up for a detached building is no
longer permissible under the 2008 code. You need the four wires.
Using the bare wire in the cable as a neutral is not allowed. You
are seeing current on the ground rod because you do not have a
good neutral connection. The ground and neutral must be separate
at a subpanel. That connection together is only made at the main
panel or the meter. Romex is not approved to be used underground
even though it is in a pipe. You need to use conductors such as
THWN or type UF cable in your PVC pipe. You are not seeing any
current on the ground rod connected to your main panel (Assuming
it is connected properly) because you have a low resistance
neutral conductor to carry the current back to the transformer.


Well, yes. That all sounds correct. Thanks.

So if one has an older detached garage with only 3 wires running is
it safe? It has been this way since 1942....

I wanted to replace the fuse panel with a breaker box and was going
to add a ground wire near the garage - I guess this is not good to do.

Any time you update pretty much anything in a structure, you're
required to update all affected systems to the latest code
requirements. Whether you can get away with replacing a fuse panel
without replacing the wiring is a question for the guy who will do the
inspection. You do know you'll have to have an inspection, don't you?
Few areas let you get away with wiring changes on your own any more.

Call the permit office in your town, and ask them what they require.

--
Steve Bell
New Life Home Improvement
Arlington, TX

SteveBell wrote:
The dude wrote:

kpg wrote:
"John Grabowski" wrote in
:
It sounds as though your wiring is in complete violation of the
National Electrical Code. #12 wire is rated for 20 amps and
should have a 20 amp circuit breaker protecting it. The three
wire plus a ground rod set up for a detached building is no
longer permissible under the 2008 code. You need the four wires.
Using the bare wire in the cable as a neutral is not allowed. You
are seeing current on the ground rod because you do not have a
good neutral connection. The ground and neutral must be separate
at a subpanel. That connection together is only made at the main
panel or the meter. Romex is not approved to be used underground
even though it is in a pipe. You need to use conductors such as
THWN or type UF cable in your PVC pipe. You are not seeing any
current on the ground rod connected to your main panel (Assuming
it is connected properly) because you have a low resistance
neutral conductor to carry the current back to the transformer.

Well, yes. That all sounds correct. Thanks.
So if one has an older detached garage with only 3 wires running is
it safe? It has been this way since 1942....

I wanted to replace the fuse panel with a breaker box and was going
to add a ground wire near the garage - I guess this is not good to do.

Any time you update pretty much anything in a structure, you're
required to update all affected systems to the latest code
requirements. Whether you can get away with replacing a fuse panel
without replacing the wiring is a question for the guy who will do the
inspection. You do know you'll have to have an inspection, don't you?
Few areas let you get away with wiring changes on your own any more.

Call the permit office in your town, and ask them what they require.


I will have to see, I am not in town. I am in a rural area.

The dude wrote:

SteveBell wrote:
The dude wrote:

kpg wrote:
"John Grabowski" wrote in
:
It sounds as though your wiring is in complete violation of
the National Electrical Code. #12 wire is rated for 20 amps
and should have a 20 amp circuit breaker protecting it. The
three wire plus a ground rod set up for a detached building
is no longer permissible under the 2008 code. You need the
four wires. Using the bare wire in the cable as a neutral is
not allowed. You are seeing current on the ground rod because
you do not have a good neutral connection. The ground and
neutral must be separate at a subpanel. That connection
together is only made at the main panel or the meter. Romex
is not approved to be used underground even though it is in a
pipe. You need to use conductors such as THWN or type UF
cable in your PVC pipe. You are not seeing any current on
the ground rod connected to your main panel (Assuming it is
connected properly) because you have a low resistance
neutral conductor to carry the current back to the
transformer.

Well, yes. That all sounds correct. Thanks.
So if one has an older detached garage with only 3 wires running
is it safe? It has been this way since 1942....

I wanted to replace the fuse panel with a breaker box and was
going to add a ground wire near the garage - I guess this is not
good to do.

Any time you update pretty much anything in a structure, you're
required to update all affected systems to the latest code
requirements. Whether you can get away with replacing a fuse panel
without replacing the wiring is a question for the guy who will do
the inspection. You do know you'll have to have an inspection,
don't you? Few areas let you get away with wiring changes on your
own any more.

Call the permit office in your town, and ask them what they require.

I will have to see, I am not in town. I am in a rural area.

Well, you might be one of the exceptions.
Call the county.

--
Steve Bell
New Life Home Improvement
Arlington, TX

The dude wrote:
....
I will have to see, I am not in town. I am in a rural area.

We're outside the City "3-mile limit" so no permits. County would
"like" them, but no legal requirement. No inspections either way. YMMV,
of course.

3-wire feed was Code-compliant until relatively recently so I personally
wouldn't worry about the panel switch out--I've done some of the farm
outbuildings for the purpose of adding an additional circuit or three
from the one or two that were run originally and where there was no
expansion room, either in the original box.

--

In the land of the unfree, and the home of the brave. How'd we let ourselves
get so regulated?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"SteveBell" wrote in message
...

Any time you update pretty much anything in a structure, you're
required to update all affected systems to the latest code
requirements. Whether you can get away with replacing a fuse panel
without replacing the wiring is a question for the guy who will do the
inspection. You do know you'll have to have an inspection, don't you?
Few areas let you get away with wiring changes on your own any more.

Call the permit office in your town, and ask them what they require.

--
Steve Bell
New Life Home Improvement
Arlington, TX

dpb wrote in :

The dude wrote:
...
I will have to see, I am not in town. I am in a rural area.

We're outside the City "3-mile limit" so no permits. County would
"like" them, but no legal requirement. No inspections either way. YMMV,
of course.

3-wire feed was Code-compliant until relatively recently so I personally
wouldn't worry about the panel switch out--I've done some of the farm
outbuildings for the purpose of adding an additional circuit or three
from the one or two that were run originally and where there was no
expansion room, either in the original box.


So 3 wire is no longer code, it must be 4. So what about in my case where
the line is run from the main panel (the meter and a bunch of 220 breakers)
and no ground is present here. The ground is in the house 'sub' panel.

How would I run 4 wires from this panel????

(I guess I could be wrong about no ground being at the meter, but my
memory is that there is none. I'll check aging later when I get home.)

"kpg" wrote in message
50...
dpb wrote in :

The dude wrote:
...
I will have to see, I am not in town. I am in a rural area.

We're outside the City "3-mile limit" so no permits. County would
"like" them, but no legal requirement. No inspections either way. YMMV,
of course.

3-wire feed was Code-compliant until relatively recently so I personally
wouldn't worry about the panel switch out--I've done some of the farm
outbuildings for the purpose of adding an additional circuit or three
from the one or two that were run originally and where there was no
expansion room, either in the original box.


So 3 wire is no longer code, it must be 4. So what about in my case where
the line is run from the main panel (the meter and a bunch of 220
breakers)
and no ground is present here. The ground is in the house 'sub' panel.

How would I run 4 wires from this panel????


*The same way the three wires are run. Pull out the existing from the
conduit and pull in new wires. If the conduit is a complete run from box to
box, I suggest that you just pull in individual conductors instead of a
cable. It will be easier and you can pull larger wires.

What size is the conduit?



(I guess I could be wrong about no ground being at the meter, but my
memory is that there is none. I'll check aging later when I get home.)