Page 133 - Electrical Safety of Low Voltage Systems

116 Chapter Six

2. For example, the earthing systems in Venice, Italy, where foundations of build-
ing are immersed in the salty water of the lagoon.
3. See App. B.
4. As per IEC 60898-1, “Electrical Accessories—Circuit-Breakers for Overcurrent Pro-
tection for Household and Similar Installations—Part 1: Circuit-Breakers for A.C.
Operation,” Consolidated Edition 1.2 (2003–07).
5. The above standard CB values were internationally adopted before World War
II and are based on the Renard geometric progression of common ratio 10 1/10 .
The Renard progression is named after its inventor, a French army officer, who
created it in the 1870s. Each term of the progression is generated by multiplying
the previous one by the common ratio.
6. Causes of the energization of the neutral will be explained in Sec. 6.9.
7. The leakage may be, for example, due to the aging of equipment. “Spilling”
current to ground causes additional consumption of electric energy.
8. See Chap. 15 for further details.
9. For simplicity, we can assume that R GT = R G .
10. The case of the water circulating in heating systems may be different, as it
may contain additives necessary to prevent corrosion. The presence of such
additives lowers the resistivity of the water.