I've been tracing the "old" ground wire from the entrance panel at my house
(built in the late 70's) and it seems that it is simply a #4 conductor
that goes only to the cold water pipe where it enters the basement.
Total run is about 45 or 50 feet. Did this ever meet the NEC?
I know that current code requires ground rods bonded at the entrance,
but I'm surprised at the skimpiness of the old system (even though
after reading the NEC I am now very aware of the importance of bonding
to the cold water pipe.)
After a number of recent lightning hits taking out DSL equipment,
I want to supplement this ground with several ground rods physically
near the AC entrance and Telco Demarc. (Luckily the Telco Demarc
is at the AC service entrance...). One way to do this seems
to be adding a new conductor from new ground rods that goes to the ground
in the entrance panel, is this correct? My reading of the NEC leaves me
with the conclusion that it is not allowed to cut the existing #4
running to the cold water pipe. I'm wondering if
a Cadweld to the "old" #4 wire underground may be allowed or even
superior. Are cadwelds forbidden in some jurisdictions for residential
grounds? My local electrical inspector didn't even know what I was asking
Is it part of NEC code that the hot water pipes be electrically bonded
to the cold water pipes too, or just common sense? My look through the
book didn't turn up a relevant section.
Ground rods aren't always required, but for most people they are. If all you
have is the water pipe,
then you need two 8' rods.
Yes, and this is how you should do it.
You have to use non-reversible connections to the grounding electrode conductor,
and welding is
specifically permitted. But why bother? Just leave that #4 to the pipe alone and
run a new #4 from
the same bus bar to your rods. You can run as many ground electrodes as you want
from the service
It is in the bonding section of article 250. All interior metallic piping that
energized must be bonded. What could be energized is at the descretion of the
drains usually no, unless you have a disposal. Hot water pipes yes because of
the water heater.
Interior gas pipes yes because of the furnace and may dryer and/or water heater.
The easiest thing
to do is just put another clamp on the hot water pipe and see if the cold water
bonding wire can
reach both pipe clamps. Otherwise, you'll need another clamp on the cold and run
at least a #10
copper between hot and cold.
Another change made recently is if your cold water pipe is also a grounding
electrode (i.e. it is
metal outside for at least 10' in the earth), then your #4 wire to the pipe must
be attached within
5' of where the pipe enters from the outside.
We just had the water heater replaced last year, and I notice that the
pipe fittings for both cold-in and hot-out have lots of Teflon tape on
them... probably meaning that there's not a good bonding. A trip to
Home Depot and $6 later, everything seems to be ship-shape.
Does a plumber doing a water heater replacement have any obligation to
check for compliance with current NEC, or does the NEC at the time of
original installation set the standard? I'm not going to go out and
sue him or anything, I just want to know if I should be generally aggressive
to make sure I'm with the latest and greatest code, not just whatever
was in effect a quarter-century ago.
I just got a new main , the ground conductor is connected to two things: the
large aluminum cable that holds the utility wires up in the air, and the
place where the main water pipe enters the basement. The electrician
specifically asked me where the water pipe comes in the house. I guess
there's a reason they put it there.
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