Gutman Schaye

Electrical Engineer 
גוטמן שי

מהנדס חשמל
http://www.sgutman.com/

  
ברירת-מחדל  |  English  |  
Is electric field in our house a fiction?(February-2014)
Maybe yes. But if is true, what we are measuring in reality with the device "AC electric field meter "? Answers to these questions are the issue of this paper.
In order to answer these questions and receive an updated explanation regarding the phenomenon, I have made several special experiments with  measurements. The experiments are described as follows, and the terms used are: “A thin cotton thread and electric field”, “Current adapter”, “1/X or 1/X2”, "Proportionality",   and "Leakage current outside".
A thin cotton thread and electric field
A thin cotton thread is connected between a source of electric field and a box from plastic filled with water. The thread is cut in the middle and connected in series with a current adapter for measuring nano amps. Yes, nanoamps (10-9-billionsh).
Figs. 1, 2 and 3 show the schematic diagram when the source of electric field is a capacitance  20 Micro F connected to the local utility only by the phase L (hot in USA). The second pole of capacitance is insulated.

 
Fig. 1. Electric field strength and leakage current measurements. F=OFF


Fig. 2. Electric field strength and leakage current measurements F=On; L=230V; Dry thread.

Fig. 3. Electric field strength and leakage current measurements. F=On; L=230V; Wet thread.
 
Figs. 4, 5 and 6 is similar to the previous one, except the source of electric field that is an air coil (PVC copper conductor 10m; 0.5mm2). The second pole of air coil is insulated.
 
Fig. 4. Electric field strength and leakage current measurements F=OFF


Fig. 5. Electric field strength and leakage current measurements F=On; L=230V; Dry thread.


Fig. 6. Electric field strength and leakage current measurements F=On; L=230V; Wet thread.
 
Figs. 7 to 11 show the measurements of electric field strength and  leakage current when a source of electric field is a capacitance 20 Micro F.
Figs. 12 to 16 show the measurements of electric field strength and  leakage current when a source of electric field is an air coil.
The experiments include 5 states:
  • F=Off
  • F=ON; L=230V; Dry thread.
  • F=ON; L=230V; Wet thread.
  • F=ON; L=230V; Wet thread; Box with water connected to ground.
  • After 30 minutes. F=ON; L=230V; Dry thread.

Fig. 7. Electric field strength and leakage current measurements F=Off.

Fig. 8. Electric field strength and leakage current measurements F=On; L=230V; Dry thread.

Fig. 9. Electric field strength and leakage current measurements F=On; L=230V; Wet thread.

Fig.10. Electric field strength and leakage current measurements F=On; L=230V; Wet thread. Box with water connected to ground

Fig.11. Electric field strength and leakage current measurements After 30 minutes; F=On; L=230V; Dry thread.
 

Fig.12. Electric field strength and leakage current measurements F=Off.
 

Fig.13. Electric field strength and leakage current measurements F=On; L=230V; Dry thread.
 

Fig.14. Electric field strength and leakage current measurements F=On; L=230V; Wet thread.
 

Fig.15. Electric field strength and leakage current measurements F=On; L=230V; Wet thread. Box with water connected to ground
 

Fig.16. Electric field strength and leakage current measurements After 30 minutes; F=On; L=230V; Dry thread.
 
The electric field strength and the leakage current measurements that appear in Figs. 7 to 16 are shown in Tables I and II.
 
Source
C= 20 Micro F		 Electric Field
E1		 Leakage Current
I		 Electric Field
E2
V/m Nano (10-9) amps V/m
F=Off 16 0.000 8
F=On; Dry thread 13685 19 420
F=On; Wet thread 13473 1365 11595
F=On; Wet thread;
Box with water
connected to ground		  
13533		  
11580		  
13
F=On; After 30 minutes 13724 19 426
Table I Electric field strength and leakage current measurements.
Source of electric field is a capacitance  20 Micro F
 
 
Source
Air coil; 10m; 0.5 mm2		 Electric Field
E1		 Leakage Current
I		 Electric Field
E2
V/m Nano (10-9) amps V/m
F=Off 16 0.000 8
F=On; Dry thread 12635 15 367
F=On; Wet thread 11783 1143 9965
F=On; Wet thread;
Box with water
connected to ground		  
10526		  
7550		  
5
F=On; After 30 minutes 12143 15 366
Table II Electric field strength and leakage current measurements.
Source of electric field is an air coil
 
The values in tables I and II highlight some important facts:
  • For source capacitance C= 20 Micro F. It is enough 1365 nanoamps (1.365 microamps) through wet thread and the box of plastic filed with water becomes by itself source of leakage current.
  • For source air coil. It is enough 1143 nanoamps (1.143 microamps) through wet thread and the box of plastic filed with water becomes by itself source of leakage current.
  • When the box with water is connected to ground leakage current increases (11580 nanoamps for C = 20 micro F and 7550 nanoamps for air coil) and the electric field strength outside the box decreases to a minimum.The same phenomenon occurs in all domestic appliances connected to local source via three wire cord (L; N; PE) such as washing machine, refrigerator, oven, computer etc. The  conductor (PE) download   leakage current to ground and the electric field strength is minimal. In old apartments where the connection to the ground is faulted and lacks local electrode, all domestic appliances connected to local source via three wire cord (L; N; PE) become by themselves sources of leakage currents.
  • In the vegetal world (trees, shrubs, flowers layers) millions of microscopic layers (Cambium and Xylem) download leakage currents to earth. The cambium is a very thin layer of tissue, sometimes only one cell thick. The xylem carries water and other nutrients up to the leaves. This explains why trees reduce the electric field strength outside.

Current adapter
It is simple, it is cheap and is enable to measure nano amps leakage currents in our house and outside. Table III shows technical data.
 
 
 
Current adapter
for
measurements
Nano amps		 Technical data
Shape Round
Wire materiel Insulated copper
Wire diameter 0.3-:- 0.4 mm
Windings 1000
Inside diameter 60-:- 80 mm
Table III Current adapter. Technical data
 
With insulated copper wires with diameters between 0.2 -:- 0.08mm it is possible to make current adapters with 10,000 windings and even 100,000 windings.   We will be able to measure 0.1 and 0.01 nanoamps. It remains the problem of accuracy due to increased ohmic resistance of the adapter.
Proportionality
There is proportionality between the measured values ​​of electric field strength and measured values ​​of leakage current? In other words, to measure the electric field strength is enough to appreciate the value of leakage current?
Answer to this question is by looking at the values ​​in Table IV based on measurements from Figures 17 to 19.
 
Fig. 17. Electric field strength measurements-for different sources
 

Fig. 18. Leakage currents measurements-for different sources
 

Fig. 19. Leakage voltage measurements-for different sources
 
 
 
Source
Leakage current		 Electric Field Leakage Current Leakage Voltage
E I1 I2 Accuracy V
V/m n A Micro A % Volt
C= 20 Micro F 13283 72600 72 +0.83 219.1
C= 5  Micro F 13199 16850 17 -0.88 134.9
Air coil
10m; 0.5 mm2		 13072 14430 15 -3.8 116.1
Proportionality  13283-13072=211
211/13072x100=
1.61%		   72-15=57
57/15x100=
380%		   219.1-116.1=103
103/116.1x100=
88.7%
Table IV Electric field strength, leakage current and leakage voltage measurements. Sources: C20 Micro F; C5 Micro F; Air coil 
 
Unequivocal, for electric field strength between 13072 to13283 V/m there is not proportionality between the measured values ​​of electric field strength and measured values ​​of leakage current.

1/X or 1/X2
By what kind of law is spreading in our house electric field strength, leakage currents and leakage voltage. In order to achieve the correct answer I used two experimental stands. The stands are described as follows, and the terms used are: "Stand 1" and "Stand 2".
 
Stand1
Figs. 20 to 21 show the schematic diagram when the source of leakage current is an insulated aluminium foil connected to the local utility 230V 50 Hz
Figs 20 to 24 show the measurements of electric field strength between two aluminium foils when the distance varies between 0.5m and 0.025m.
Figs 25 to 27 show the measurements of leakage current between two aluminium foils when the distance varies between 0.5m and 0.025m.
Figs 28 to 30 show the measurements of leakage voltage between two aluminium foils when the distance varies between 0.5m and 0.025m.

Fig. 20. Stand 1. Two aluminium foils.- Schematic diagram


Fig. 21. Stand 1. Two aluminium foils
 

Fig. 22. Electric field strength measurements
  d=0.5 to 0.25m;  X=1 to 0.5
 

Fig. 22. Electric field strength measurements
   d=0.225 to 0.1m  X=0.45 to 0.2


Fig. 22. Electric field strength measurements
   d=0.075 to 0.025m  X=0.15 to 0.05


Fig.25. Leakage current measurements
  d=0.5 to 0.25m  X=1 to 0.5

Fig. 26. Leakage current measurements
  d=0.225 to 0.1m  X=0.45 to 0.2


Fig. 27. Leakage current measurements
  d=0.075 to 0.025m  X=0.15 to 0.05


Fig. 28. Leakage voltage measurements
  d=0.5 to 0.25m  X=1 to 0.5


Fig. 29. Leakage voltage measurements
  d=0.225 to 0.1m  X=0.45 to 0.2


Fig. 30. Leakage voltage measurements
  d=0.075 to 0.025m  X=0.15 to 0.05
 
The electric field strength, leakage current and leakage voltage measurements that appear in Figs. 22 to 30 are shown in Table V.
d X=d/0.5 1/X Electric Field Leakage Current Leakage Voltage
m     V/m Nano (10-9)Amps Volt
0.5 1 1 2223 530 5.16
0.45 0.9 1.11 2577 603 5.93
0.4 0.8 1.25 2904 725 6.90
0.35 0.7 1.428 3279 826 8.10
0.3 0.6 1.66 3837 967 9.65
0/25 0.5 2.00 4437 1196 11.82
0.225 0.45 2.22 4810 1308 13.27
0.2 0.4 2.25 5200 1534 14.94
0.175 0.35 2.85 5760 1700 16.81
0.15 0.3 3.33 6376 2040 19.24
0.125 0.25 4.00 7109 2360 23.14
0.1 0.2 5/00 8025 3130 28.69
0.075 0.15 6.66 8982 4070 38.40
0.05 0.1 10.00 10473 5470 56.50
0.025 0.05 20.00 12251 10920 108.60
Table V. Stand 1
Electric field strength, leakage current and leakage voltage measurements 
d= 0.5 to 0,025m X=1 to 0,05
 
Stand 2
Figs. 31 to 32 show the schematic diagram when the source of leakage current is a PVC copper conductor 5m, 0.5mm2 connected to the local utility 230V 50 Hz only by the phase L (hot in USA). The second pole of conductor is insulated.
The measurements are similar to the Stand 1 and summarizes in table VI.
 
Fig. 31. Stand 2. PVC copper conductor 5m, 0.5mm2 Schematic diagram
 

Fig. 32. Stand 2. PVC copper conductor 5m, 0.5mm2
 
d X=d/0.5 1/X Electric Field Leakage Current Leakage Voltage
m     V/m Nano (10-9)Amps Volt
0.5 1 1 1502 386 3.96
0.45 0.9 1.11 1683 442 4.49
0.4 0.8 1.25 1920 501 5.13
0.35 0.7 1.428 2154 583 5.85
0.3 0.6 1.66 2480 664 6.73
0/25 0.5 2.00 2846 800 8.06
0.225 0.45 2.22 3075 866 8.65
0.2 0.4 2.25 3310 958 9.57
0.175 0.35 2.85 3643 1074 10.68
0.15 0.3 3.33 3990 1232 12.14
0.125 0.25 4.00 4380 1416 13.86
0.1 0.2 5/00 4884 1640 16.06
0.075 0.15 6.66 5546 2030 19.66
0.05 0.1 10.00 6422 2740 26.09
0.025 0.05 20.00 8290 4380 40.10
Table VI. Stand 2
Electric field strength, leakage current and leakage voltage measurements 
d= 0.5 to 0,025m X=1 to 0,05
 

Comparisons between predicted theoretical and measured values of electric field, leakage current and leakage voltage that appear in Table V and Table VI are display in Fig. 33 as graphs.
If the graphs of leakage current and leakage voltage indicates a similar characteristic between the predicted theoretical value and the measured value, the graphs of electric field dramatically illustrate a big difference between the theoretical value and the measured value for d= 0.4 to 0.025m
The discrepancy between predicted theoretical and tasted values can be explained by the fact that the sensor of AC electric field meter "is in the top of 1/3 of meter".(See Fig. 34)
It is very significant to note that graphs leakage current and leakage voltage from stand 1 indicate almost perfect coincidence between the predicted theoretical value and the measured value.
 
Fig. 33. Stand 1. Stand 2. Graphs
 

Fig. 34.  AC electric field meter. Technical data.

 
Leakage current outside
Figs 35 show the measurements of leakage currents on the street under overhead power distribution line 22kV. The measurements highlight the offsetting phenomenon of leakage currents.
 
 
Fig. 35. Overhead power distribution line 22kV.
Leakage current measurements
 
 
Conclusions
The following conclusions arise from the above experiments:
  • Only measurements of leakage currents or leakage voltage  can give us a true and accurate approximation of the currents passing through the body in every corner of the house.
  • The spreading law of leakage currents in our house is 1/X.
  • In house space our body, that  contains 70% water, acts like a small black hole and absorbs leakage currents and becomes by itself source of leakage currents.
  • What is the permitted level of leakage current in the house? Still do not exist recommendations. In my house I have managed to decrease the leakage current as follows: at the computer and work table between 20 to 25 nanoamps in my sleeping area  8 to 10 nanoamps. 
Recommendations
Is it worthwhile to measure leakage current or leakage voltage of our body (3D sensor) in relation to ground?
Definitely. Yes. To measure at home (sleeping area, computer, work table), at school, in hi-tech companies and in all institutions where people use electrical appliances connected to local source via two wire cord (L;N ).
Maybe it's time to legislate the use of shielded conductors in kindergartens, schools, sleeping rooms.
Remember, the human body has the ability to repair itself while it sleeps, but high level leakage current because external sources,  (live electrical wiring in ceilings, walls and floors , electrical appliances on the bedside chest ) is thousands of times stronger than the body’s own electrical system. Long-term exposure to these  high level leakage current can impair the body’s ability to communicate within itself and impact health.