Wind Cone @ Airport

[beanland]

I have a 30+ year old wind cone at an airport. It has incandescent lights that operate at 120VAC. The original service is about 2000' of direct buried 5kV #8, two conductors, hot and neutral, operated at 120VAC. Wind cone steel is grounded with local rods. It will be replaced next year but I need to replace part of the branch circuit to accommodate construction. We have conduit in place for the first 500 feet and the ultimate branch circuit will be 600V 4-conductor (HHNG). Can I run my new HHNG to a handhole and connect HN to the existing direct buried HN to maintain service? Next year, we will have conduit and HHNG all the way to the new wind cone. But, this is more than 90 days away. Would installing a GFCI breaker to feed the temporary no-egc circuit be required/needed? (There are no receptacles involved)

 

[kevost]

I worked at an airport for two years as an airfield electircian and I have never seen any circuit that goes 2000' and runs at 120v (I would think the voltage drop is to great for a #8 wire). Is the wind cone on a constant current regulator (this is an item specific to an airfield)? If it is on a regulator, there is a transformer in the ground near the wind cone and the primary circuit is on the regulator operating at upto 5000v for distance and load (hence the 5kv wire). The primary circuit is a two wire series loop-it goes out of the regulator to each location, hits a step down transformer then continues on to the last device then back to the regulator (the transformer is in series). The leads from the transformer then go to the light or wind cone. The voltage can vary on the secondary side of the transformer. To tell if you have this kind of circuit, check the bulb installed in the cone. If it is a special buld then you may be on a regulator, if not I have never seen the set up you have with those distances. Good luck.

 

[beanland]

No CCR

No CCR

There is no CCR. I don't think anyone cared much about the voltage drop. As long as the lamps were lit, all was OK. There is a 6.6A CCR for the MIRL and a new set of 6.6A PAPI are coming.

The problem is the temporary for the 120V wind cone circuit. Can I feed an existing 2-wire (HN) circuit from a new 3-wire (HNG) circuit? No equipment bonding conductor!

 

[cadpoint]

Can't this well be covered in the spec's. the service is to maintained.

Shoot electrician's still like a challenge.... :grin:

 

[beanland]

Ahj

Ahj

I want to make sure that the AHJ will not be able to say "Per 2008 NEC xxx.xx(x) this cannot be done." If no one knows an NEC reason why it cannot be done, I will cross my fingers and proceed.

 

[KevinVost]

I would inquire of the AHJ and get their decision on the "temporary" status of the installation. Here, we allow certian temporary installs to go with out inspections if they are under a permit and will be for a short, designated amount of time. At the very least I would put in some type of GFP for the circuit since the EGC is not going to be connected. Good luck.