Low voltage over top of high voltage
Low voltage over top of high voltage
(OP)
We have a situation where it would be advantageous to run a higher voltage power line (34.5 kV)underneath of a lower voltage (4.16 kV)power line. Both lines are on poles, but serve only our needs - mining. Assuming that we maintain adequate clearances, are there any rules/standards to prevent us from doing so? I have not seen the lines personally, so I do not have any additional information.
Regards,
Raisinbran
Regards,
Raisinbran






RE: Low voltage over top of high voltage
RE: Low voltage over top of high voltage
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I have been called "A storehouse of worthless information" many times.
RE: Low voltage over top of high voltage
RE: Low voltage over top of high voltage
If the lower voltage line has any transformers then there may be serious access issues for your servicemen.
RE: Low voltage over top of high voltage
RE: Low voltage over top of high voltage
RE: Low voltage over top of high voltage
_____________________________________
I have been called "A storehouse of worthless information" many times.
RE: Low voltage over top of high voltage
RE: Low voltage over top of high voltage
Table 235-5, which lists vertical clearance for conductors on the same structure, lists clearances for "Conductors and cables usually at upper levels" and "Conductors... usually at lower levels". The box corresponding to 4kV above 34.5kV is blank.
Seems clear this is not the preferred approach, but there may be some wiggle room for special applications. Perhaps you can use the 34.5 kV clearances for both circuits.
RE: Low voltage over top of high voltage
I have also seen an instance of service entrance running unbroken as aerial cable from a Duquesne Light Company pole to the top of a meter socket. This configuration was eventually outlawed in the early 1970s because stranded wire and service cables both act as poor excuses for water hoses.
Also, elastomeric potheads for single conductor shielded cable can be installed with the cable going into the top and the lug for open wiring on the bottom. Some electrical utilites do that for bringing power from an upper circuit past a lower circuit such as on dual circuit lines. The line fuses and transformers can then be below the lower circuit.
Rural Utilites Service does have a specification for mounting single phase transformers so that they are NOT directly underneath a single phase primary hot wire.
Every once in a while an electrical utility has a strange installation practice.