Satellite antenna lightning protection

[Gerry_G]

I had "lightning" on my brain and posted this under "lighting". I think it belongs here. Oops


Starlink Services (rural, VERY HIGH SPEED, satellite internet, in the US and 17+ other countries so far) only supplies a phased array antenna dish with a custom 100' shielded Ethernet cable permanently attached. The antennas are usually mounted high, on a high mast or tower. The antenna is very uniquely, not what most are accustomed to with satellite internet. The phased array needs a fairly wide view of the sky since the satellites are not stationary and the phased array switches what satellite it "talks to" very frequently. The custom cable also needs to supply ~100 W to the antenna. Standard Ethernet cable can't handle that power level @ 56 V.

They only support running that cable into a building with no lightning protection, not even grounding/bonding the shield at the building entrance. There are reports of lightning strikes destroying (literally blowing apart) the power supply inside the house and disintegrating the custom cable to the antenna. The only "ground" is inside the building at the power injector. The only ground is via the 3 prong 15 A power supply cord.

This appears to be very dangerous, folks are mounting the antennas high, thus prone to attracting lightning.

Their minimal FAQ https://www.starlink.com/faq contains:

"Starlink meets the U.S. National Electrical Code (NEC) grounding requirements and includes the necessary lightning protection. However, any user who lives in an area with lightning should have the appropriate lightning protection installed in accordance with your local electrical code prior to using Starlink." (bold my emphasis).

However, their support replies to never cut the or extend the supplied cable, thus one can't even ground the shield at the building entrance. Also, being non standard cable, one can't even use an available CAT 5e/6 protection unit at the building entrance.

I don't believe Starlink's configuration meets the NEC re lighting protection.

Am I correct, if so, any suggestions?

 

[don_resqcapt19]

See 810.20.

 

[jaggedben]

It's unclear to me if their configuration has a true 'antenna lead in'. I'll defer to others expertise on that. More generally though, the NEC doesn't really contain any lightning protection requirements so alleging that their configuration doesn't meet the NEC re lightning protection isn't really saying much. NFPA 780 is a standard for lightning protection, and a system installed to that standard might suffice as 'appropriate lightning protection' per their statement.

Their statement that their equipment 'includes the necessary lightning protection' is not so apt in my opinion. 'Necessary' is quite subjective. They would probably be better off claiming that their system meets legal and perhaps product standard requirements, since as far as I know there aren't really any such requirements so they'd be easy to meet.

 

[Gerry_G]

It has an antenna, so it is an antenna with conversion. The NEC section 810 and 820 explicitly requires ANY CABLE (except a 120 V underground branch) to have lightning protection at the point of entrance of the building. Full suppressors can be used but a shield grounding block is allowed for shielded cables. The NEC is published by the NFPA (The National Fire Protection Association) and grounding the shield only protects against building fires, not equipment damage which requires a surge protector. Even rotator cables need protection. Note. Starlink's FAQ ends with complying to code yet Starlink has no provision for such, not even a Shield bond connector (also called “bullet-bond”).
Reference, for coax, see Fig. ):

http://www.reeve.com/Documents/Articles%20Papers/Reeve_AntennaSystemGroundingRequirements.pdf

 

[hbiss]

I agree that it is an antenna with lead-in and I don't see how an installation can be done to meet NEC Art 810 requirements. Truth is though that an NEC compliant installation will only serve to drain off static charges, it offers no protection against a close or direct strike which I suspect is what those reports you talk about are.

Several things I see here. One is that these seem to be "self" or DIY installed. That's probably by design which is why there is no flexibility with the cable- it's not likely that a DIYr is going to be able to deal with connectorizing their cable to allow for a SPD device where it enters the building. It may be also that the 100 foot cable length is figured into the design of the system. Shorter or longer may cause problems.

Also, "folks are mounting their antennas high" raises concern. It looks like because these are DIY installs the expertise and knowledge to locate the antenna with regard to what it actually is is lost to thinking that higher is better (like with old TV antennas) and not wanting to clear obstructions like trees.

Another is whether this system is listed. The claim that the system meets NEC grounding requirements needs to be substantiated either by a UL listing or otherwise. It may be that as a manufacturer they are able to get their product listed without actually being able to meet Art 810 requirements. But I don't know and a search of the listing will tell.

-Hal

 

[Gerry_G]

I agree that it is an antenna with lead-in and I don't see how an installation can be done to meet NEC Art 810 requirements. Truth is though that an NEC compliant installation will only serve to drain off static charges, it offers no protection against a close or direct strike which I suspect is what those reports you talk about are.

Several things I see here. One is that these seem to be "self" or DIY installed. That's probably by design which is why there is no flexibility with the cable- it's not likely that a DIYr is going to be able to deal with connectorizing their cable to allow for a SPD device where it enters the building. It may be also that the 100 foot cable length is figured into the design of the system. Shorter or longer may cause problems.

Also, "folks are mounting their antennas high" raises concern. It looks like because these are DIY installs the expertise and knowledge to locate the antenna with regard to what it actually is is lost to thinking that higher is better (like with old TV antennas) and not wanting to clear obstructions like trees.

Another is whether this system is listed. The claim that the system meets NEC grounding requirements needs to be substantiated either by a UL listing or otherwise. It may be that as a manufacturer they are able to get their product listed without actually being able to meet Art 810 requirements. But I don't know and a search of the listing will tell.

-Hal

The power injector is UL listed but and the system is EMI certified in an anechoic chamber. The NEC does not provide "listing", rather it is the US gold standard code. A properly bonded/grounded shield ground at the exterior building entrance will most likely prevent a building fire. That is what the NFPA is all about! Starlink clearly states to comply with lightning codes yet provides no way to comply.

The reference I included states that the NEC is poorly written. There are building entrance suppressors with PoE and shielding but Starlink will not "support" one if the cable is modified or extended. The choke at the PoE injector box is clearly there to get EMI certification from the PoE box.

I believe this is a lawsuit waiting to happen! When somebody's house catches fire and insurance declines a claim because the installation doesn't meet code - they clearly state "However, any user who lives in an area with lightning should have the appropriate lightning protection installed in accordance with your local electrical code prior to using Starlink." at the very bottom of their FAQ. One even has to expand it to read that line!

gerry

 

[hbiss]

the system is EMI certified in an anechoic chamber. The NEC does not provide "listing", rather it is the US gold standard code.

EMI means nothing to this discussion. The listing is provided by a NRTL like UL. The listing can supersede the NEC but in this case I don't think anything but the power injector is listed.

-Hal