Holaday Industries HI-3624, Руководство пользователя

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Page 12 HI-3624 / HI-3624A Manual
or air conditioning systems turn on or the compressor within a
refrigerator cycles on, the flux density will increase.
Measurements must take this condition into account and it is
recommended that, when taking measurements in a room, the
meter be watched for a period of time to observe for
fluctuations in the indicated value of flux density. After some
experience, it may be possible to relate the observed
fluctuations to various uses of electricity within the home.
A phenomenon which has recently received some attention in
regard to residential magnetic fields is the flow of earth currents
via plumbing lines or telephone cables buried beneath the
home. In some cases, it has been noted that 60-Hz magnetic
fields exist within a home, even when the home is not using any
electrical power (the circuit breakers have all been turned off at
the main electrical service box of the home).
This observation has, in some cases, been related to the flow of
currents beneath the home on pipes or cables. It is not unusual
for currents, related to other neighbors' use of electricity, to
flow back to the electrical supply via low resistance paths
formed by metal plumbing pipes or wires used for telephones as
opposed to the electrical system neutral wire. In such cases, it
is possible to measure magnetic flux densities within the home
without any apparent reason if the power to the home has been
shut off.