Is the earth of the water service faucet effective?
The earth cable might often tie to the faucet of water service when it is not possible to ground it easily by an electric washing machine etc.Is this effective as the earth?
It is mostly made of the iron tube. wall about the water service tubeGenerally, the one made of the hard chloridization vinyl pipe seems to be abundant about 1-3 meters are iron tubes ..there.. ahead from there. The iron tube seems to have from it to the polyethylene pipe ahead in the small portion recently.
Measurement of earth resistance of water service faucet
 Then, the ground resistance of such the one was measured.
It is a faucet that I who understood the structure first set up. It is connected with the well pump grounded by hard chloridization vinyl (VP20) about 3m ahead of that by a left faucet's using the copper pipe of 7/8 inches by about 1m. There are a lot of impurities of the well water of my home, and there is one gram or more, and the total solid in the water of one liter can be said that it will conduct electricity easily from tap water. It was an incapable measurement because it was able to measure even only 1k Ohm in the earth ohmeter that I was using. When the polarity was changed with the tester and resistance with the iron frame was measured quick, it became about 40k Ohm because the ground resistance of the iron frame in the building of my home was about 6 Ohm. With this, it is completely understood not to use it as an earth. (The polarity is changed to decrease the influence of the polarization action by the generation of the battery with the earth pole and electroanalysis because the tester is direct current and measure it quick. ) It is necessary to make below 100 Ohm or to make using with the leak breaker of a high sensitivity high-speed type together below 500 Ohm if it uses it as an earth (D earth). |
Whether it is grounded is simply seen with the tester
The method of seeing the standard whether grounded with the
tester includes the method of simply measuring the power supply side of
100V and the voltage between earths. The tester was made AC120V cooking
stove (internal resistance 8k Ohm/V), and the voltage side of the outlet
of 100V and the voltage between these water service earths were measured.
There were 96V. Internal resistance of the tester 8k Ohm*120=960k
Ohm Because the ground resistance of and this water service
is 40k Ohm, 96V is values the same as the calculation.
This value becomes and the ground resistance of this water
service earth becomes about 10k Ohm even 99V. With this, it is not effective
at all as the earth.
This method seems not to be suitable as the method of simply
measuring the ground resistance. If it is a ground resistance of 1k Ohm
or more, if internal resistance of the tester is adjusted to about 10k
Ohm (About 10 thek Ohm resistance is obtained for the tester in parallel),
it is possible to measure it simply. However, there is a possibility that
the leak breaker operates if the current of this circuit becomes about
10mA, and other leaks exist. (A usual leak breaker operates by 15-30mA.
)
Measurement 2 of earth resistance of water service faucet
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Next, it is a measurement of the ground resistance of a single faucet that
becomes it for the mop washing of the bathroom of my home. This is connected
with town waterworks. When the appearance in the below the floor level is seen,
it is buried with the iron tube by about 10cm in the soil through mesne of the
block wall as shown in the photograph on. The soil is always damp. It is laid
from it ahead with the hard chloridization vinyl. A right photograph is the one
that the pipe of the faucet tied to the earth with the earth stick etc. because
this faucet had been used for the washing machine before. This was removed and
measured this time.
When the ground resistance was similarly measured
with the tester, it was about 2.5k Ohm. The
ground resistance seems to fall if still buried in the soil even a little. It
can be said that it is not suitable for this to use the faucet of water service
as an earth.
Calculation of resistance of water in chloridization vinyl pipe
The resistivity p of the river water and the water supply
Chloridization vinyl pipe VP20 Resistance R at both
ends of water in 1m is calculated. The inside diameter of the pipe is 2cm.
R = p L / S
= p L / 3.14 * r2 (L =
100cm r = 1cm)
When it blows and being possible to come is calculated About
32-640[k Ohm] It becomes it. Resistance in the vinyl chloride
pipe of 3m : for above-mentioned "Earth resistance measurement 1 of
the water service faucet". About 2 about 100k Ohm -M Ohm It
is sure to become it. Measurement value 40k Ohm seems to be effective more
than the resistance of water of the insulation resistance between the pipe
and the wall of copper because it is considerably smaller than this.
As for water in the water service pipe, the thing that hardly contributes to the
ground resistance of the faucet earth (below 100 Ohm or 500 Ohm) is understood as
a result.
The insulation pipe of 1m will be installed in the hot water
side of 50cm on the water side of an electric water heater for the electric
shock prevention. Because it is a thing that water can be insulated by this
length, the thing that should not be able to be grounded in the water service
tube of the chloridization vinyl is understood from this thing.
Because it doesn't diffuse, and the current density is constant, the
ground resistance doesn't fall on the current that flows in water in the
chloridization vinyl pipe though the current diffuses in all directions as
follows and the ground resistance lowers to the earth driven to the soil.
Conclusion
The earth of the water service tube might be not effective at all. It is not possible to use it as an earth if it doesn't measure it with the earth ohmeter. When everything of course has been buried with a metallic tube in the soil by a long distance, it is effective.
