Solar Powered Helipd Lighting

[mkgrady]

I’m getting ready to install lighting for a helipad. The helipad is existing and privately owned. It will get very little use. The owner has purchased a package that consists of a control panel, a solar panel with battery and all of the required lights. All the lights operate at 24 volts. A cool feature of the system is that it remains dormant until a pilot approaches and turns it all on by way of radio control.

I have a couple of questions:

Does the NEC apply? Assuming it does, what would be the minimum depth of the conductors?

I assume a bad idea would be direct buried LV wiring but I’m not sure it would violate any code.

I have not seen the lights but I assume they have some kind of in ground box that I would run conduit in and out of.

I’m thinking schedule 40 PVC underground and 80 where it comes out of the ground. Nearly all the lights are installed flush to the ground. An exception would be a lighted wind sock and an optional flood light. I think the flood would not be on until the helicopter lands.

The existing ground surface is asphalt pavement. One complexity is that the asphalt is on top of an old military runway. I assume an old fighter jet runway would have a very thick reinforced concrete base. That would make trenching low enough for conduit to sweep into the bottom a real chore.

Any feedback would be appreciated.

The other above ground lights are on a perimeter fence.

 

[jaggedben]

The NEC applies. However if everything is operating at 24V or less then I think there would be relatively few meaningful NEC restrictions on what you could do. Protecting PV conductors kicks in at 50V, if I recall correctly.

 

[iceworm]

Can you elevate the equipment on a pedestal/box so the sweeps will be vertical when they get up to the equipment?

I have worked a few similar installations in an arctic environment - gravel, not asphalt. I used shallow trenching, with hell-for-stout steel plates, 1" as I recall. I had a fear of the prop wash moving/flipping the coverplates. The equipment was up on steel boxes.

 

[mkgrady]

Can you elevate the equipment on a pedestal/box so the sweeps will be vertical when they get up to the equipment?

I have worked a few similar installations in an arctic environment - gravel, not asphalt. I used shallow trenching, with hell-for-stout steel plates, 1" as I recall. I had a fear of the prop wash moving/flipping the coverplates. The equipment was up on steel boxes.

I’m sure this customer will want everything flush with the asphalt (except the wind sock, control panel and fence perimeter lights) so they can walk all over the lights without tripping.