30
Potheads and stresscones provide mechanical support and electrical insulation for
conductors like cable. Insulating capability of these devices is important to prevent a
fault and resulting forced outage.
conductors like cable. Insulating capability of these devices is important to prevent a
fault and resulting forced outage.
Maintenance or Test
Recommended Interval
Reference
Visual inspection for leaks,
cracks
cracks
Annually
NFPA 70B, 8-2.4 and
Appendix H
Appendix H
Doble AC loss measurement
(hot collar)
(hot collar)
3-6 years
FIST Volume 3-1
Doble Reference Book on
Cables and Accessories
Doble Reference Book on
Cables and Accessories
Infrared scan
Annually
NFPA 70B, 18-17
Voltage regulators are static devices operating at power system voltages and
frequencies to maintain stable voltage. De-energization is required for some
maintenance. (For excitation system type voltage regulators, see section 16 on
exciters, earlier in this volume).
frequencies to maintain stable voltage. De-energization is required for some
maintenance. (For excitation system type voltage regulators, see section 16 on
exciters, earlier in this volume).
Maintenance or Test
Recommended Interval
Reference
Doble power factor
5 years
Doble Power Factor Test
Data Reference Book
Data Reference Book
Infrared scan
Annually
NFPA 70B, 18-17
Protective relays monitor critical electrical and mechanical quantities and
initiate emergency shutdown whenever they detect out-of-limits conditions.
initiate emergency shutdown whenever they detect out-of-limits conditions.