I am extending the ground for the service panel with two 8' rods because the
pipes were re-done in PVC. I plan to attach #4 wire to the end of the
existing #6 wire with two copper split-bolt connectors and make the
connection real tight. I have been reading that the copper ground wire
should be one continuous wire. However I pefer not to mess with high
voltage and take apart the service panel to make it one continuous ground
wire. Are the split bolt connectors sufficient or is there some "physics"
reason it must be one wire? Or is it to prevent someone from accidentally
un-screwing the bolt?
One continuous conductor, unless spliced with an irreversible connections
such as an exothermic weld (solder is not good enough). Do you have access
to a good torch? I would use a split bolt connector and then after
tightening it braze shut it with 40% silver solder. Solid #6 wire should
be enough; no need to use #4 unless the wire is subject to being damaged by
a lawn mower or something.
Exothermic welding is a chemical weld, not brazing.
They refer to a product like CadWeld which is a copper laden thermite
type powder. You put a mold around the joint, pour it full of this
powder and light it. When the fire goes out you have a solid mass of
copper around the joint.
If he can get to the first rod with the copper he has he can jumper to
the second rod.
I understand that; a thermite weld. I think brazing (with silver) a copper
or bronze split bolt connector so it cannot be loosened is a reasonable
Copper is extraordinarily hard to weld.
Thank you Bob, I'll braze the split bolt connector. I have a torch that I
used years ago to fix a copper water pipe. I don't remember how to solder
with it but I think I can find some crash course on the net. Still a bit
curious how this affects the physical properties of the electricity running
through the wire.
Please don't do that. No offense, but you'll probably just make a mess
of it. Even if you can make a decent braze, brazing is not accepted by
NEC. Here is an acceptable ground clamp, readily available at Home
Usually referred to an "acorn nut," the one in the link is for 1/2"
ground rods. They are also available for 5/8" rods. It helps to slide
the acorn nut(s) onto the the ground rod _before_ driving it, if using
a sledge hammer, as the head tends to mushroom, making it a PITA to
install the acorn nut after the fact.
Pete C and gfretwell had some good suggestions. If I were doing it, I
would drive the first ground rod as close to the electric service as
possible, preferably 18" away from the house so it is at or outside of
the roof drip line. Drive the second rod one rod length away from the
first rod and trench between the rods. The deeper the better. I use
#4 bare copper since it is not required to be protected. As Tom Horne
has stated in other threads in this NG, if you're going to do all that,
it would be better and about as much work to establish a "ground ring"
while you're at it. A minimum ground ring would require using #2 bare
copper at least 20 feet long and buried at least 30 inches.
After driving the rods (preferably 5/8" copper), run the wire from the
panel to the first rod, through the acorn nut without slice then on the
the next rod. Then working your way back to the panel, connect the
wire to the second rod, tighten the ground clamp at the first rod, then
connect to the panel. De-energize the main panel breaker before
removing the original grounding system wiring.
If you still insist on using a split bolt, which is not acceptable by
NEC if the splice is before the first rod, at least use one that is
listed for the purpose, which usually means using one made of brass,
overlap the wires about one foot and use two split bolts.
Good tips. I should note that the existing ground wire coming out of the
service panel ends at a clamp on a copper pipe. This copper pipe was cut
somewhere not too far under the ground for the PVC. I wasn't around when
this re-piping project was done, but I am getting crazy voltages, 134V at a
couple outlets, and 4V difference between this ground wire and the fence
post, so I'm sure this is part of the problem. I was intending to leave the
copper pipe clamp like it is and just "extend" the system so it can also
benefit from this little pipe section. I will make sure it is done right,
probably leave some extra wire near the service panel till I figure out how
to make the connection.
at an outlet and you will never stop having voltages between differing
grounds. The advice you have been given is good, you need a good ground and
it needs to be done according to all applicable codes. Having 134 volts at
an outlet can only be a result of excessive input from the power company or
a high resistance in the neutral line. Having voltages between different
grounds is perfectly normal and will always exist.
It turned out to be a power company problem. While driving in the ground
rods I looked up and noticed that the neutral line connector was broken off
at the power pole! So I called out the power company and Southern CA Edison
showed up within an hour to fix it. Now the voltages are reading normal at
If you have interior metal water pipes, IMO, you should leave that wire
and clamp alone, other than to check to see that it is tight, or to
replace the clamp if it is corroded. If your interior water pipes are
metal and that wire is removed, in the event that the pipes
accidentally become energized by a circuit or equipment, a serious
shock hazard will exist. Also, if your interior pipes are metal, and
the water meter is inside the house, it should be jumpered. The hot
water line should also be jumpered to the cold water line at the water
heater. Same for any water conditioning equipment, etc.
This is exactly why NEC requires that an underground metal water used
to ground an electric system be supplemented with a ground
rod....somebody comes along and replaces the underground water pipe
with plastic. IIRC, this requirement came about around 1978 or so. If
your house is newer than that, you may want to take a closer look and
try to find a wire that may already go to a ground rod.
You could drive the ground rods and run the wire, leaving enough extra
wire to reach both the panel and the old connection at the water pipe.
That way when the electrical contractor comes to make the connection
they will have a choice. Even though the NEC permits them to make a
crimp connection to the wire at the water pipe, they may refuse to do
it. I know I would. It's better practice and easier (for someone
willing to go into the panel) just to take it to the panel.
Since you don't feel comfortable getting inside the panel, I think
Pete C.'s suggestion was best.....do all the other work, then call a
qualified electricial contractor to make the final connection to the
panel.....while they are at it they can check what you did to be sure
everything is OK.
Proper electric system grounding is critical, and unfortunately,
improper grounding is usually not evident until a fault occurs, then
it's too late.
If you do decide to make the connection to the panel, for safety,
especially in this case, since you have no existing system ground, it's
important that the final connection to the panel be made while the
panel is de-energized.
It would probably be best to call your local electrical inspector to
see if an inspection is required.
Yes, Bob. You do that and it will be more than enough.
It will last a few hundred years, at least..
Don't listen to all the crap I'm hearing from the jerks that want you
to spend a fortune on some fancy overkill stuff.
It should, but that's up to the inspector (if there is one.)
A split bolt connector is a compression joint. When you solder the threads
(especially using hard solder), you've made it irreversible.
Just make sure it looks neat. Don't try to solder or braze the wires, the
silver solder is just to make the split bolt connection permanent.
If you can find an electrical inspector who will pass a hack job like
that, I'd like to know his/her supervisor's name. Now that you bring
it up, making major changes to an electric system ground _is_ something
that should be inspected by a local electrical inspector, if there is
The NEC is very clear that the grounding electrode conductor must be
continuous, without splice. The NEC also realizes that buildings get
remodeled and that situations, such as the OP's, do occur. For those
reasons the NEC, specifically (2002) Section 250.64(C), does permit
splices to be made and _only_ made by an "exothermic welding process",
i.e. CadWeld, or by "irreversible compression-type connectors LISTED
for the purpose."
A silver-soldered split bolt is _not_ a listed irreversible compression
type connector. Both a CadWeld and the tool required to crimp the
irreversible connectors are beyond the capabilities of most residential
electrical contractors, mostly due to cost, let alone a home owner.
Cadweld does make a disposable One Shot, but that is for connection of
wire to ground rods. AFAIK, CadWeld doesn't make a wire to wire One
Shot. The OP could call around and find a commercial electrical
contractor who may rent him a crimping tool for irreversible
connectors, but that would probably be cost prohibitive too.
As long as it's neat a hack job is OK? I once saw a house wired with
lamp cord. Sure was neatly installed, though. Just one of those
things that one just doesn't believe until one sees it. I once found a
120 volt duplex receptacle wired with telephone wire, but it wasn't
neat, the wire wasn't stapled.
All this, just because the OP doesn't feel comfortable getting inside
the main panel, and now you've got him out in the dirt with a torch?
I've been doing electrical work for 30 years and I've yet to see an
electrician with a torch, with the exception of maybe using a propane
torch to dry out a damp CadWeld mold before using it, or to fire off
the starter powder because his ignitor took a dump.
Good advice! Just want to add, to help the 'grounding' effect, the
code requires those rods 6 feet apart, but make them 8. Easy way to
do this, drive the first one, then lay the second one on the ground,
and then that's 8 feet.
The idea about the splice, it should be in such a way that over a long
time, nothing can work it's way loose. The grounding system with the
rods stablizes voltages and can help extend the life of many of your
home's electronics. So it's a good idea to follow the NEC
requirements, and do it once right.
Remember, not your electrician, so just my options. ;)
tom @ www.Florida-VOIP.com
It's due to the destructive power of a lightning strike.
The idea is to make it as easy as possible for the lightning to get to
ground without damaging anything. There aren't supposed to be sharp
bends in the wire to the ground rod either. The wire isn't supposed to
be wrapped around anything. It's supposed to be as straight as
possible. #6 is specified since a ground rod can handle only so much
current anyhow. Going to a larger size wire won't help a whole bunch.
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