Lightning protection for guyed tower
Lightning protection for guyed tower
(OP)
I am structural engineer and I need to gain some knowledge on how to protect a steel tower, triangular in cross section, it is 30 foot high, it has three guy cables that are equally spaced around the tower. The cables are connected to a steel frame/collar and clamped to the tower frame. The other end of the cables is connected to a guy connector which is embedded into a concrete footing.
Near all three cables ground area, I have placed three (3) 0.75 inch diameter rods by 20 foot long. The three rods are in triangular configurations with 10 foot spacing.
Is this adequate? Do I need to bond the tower itself to the grounding system as well?
Please let me know.
Near all three cables ground area, I have placed three (3) 0.75 inch diameter rods by 20 foot long. The three rods are in triangular configurations with 10 foot spacing.
Is this adequate? Do I need to bond the tower itself to the grounding system as well?
Please let me know.






RE: Lightning protection for guyed tower
The three rod grounding electrode (also known as counterpoise grounding electrode) should be provided at EACH of the three guy wires PLUS the steel tower. More importantly at the towers base then the guy wires as the tower is the the path of least resistance to the lightning currents.
You also must interconnect all the grounding electrodes, in this case all four 'electrodes', using a buried copper conductor no less than #2/0 in size.
Sounds like this is already built. HOwever, best (and almost free) grounding electrode is obtained when you use the concerete foundation with re-bars (for the steel tower if applicable) as the grounding electrode. In that case need to bond the steel tower to the rebars. You can also bury a bare copper conductor at the bottom of the foundation and bond it to the steel tower. Use min. of #2/0 or #4/0 copper conductors.
RE: Lightning protection for guyed tower
Visit
http://www.lightningsafety.com/nlsi_bus/nfpa-780-2004.h...
http://www.nfpa.org/Codes/NFPA_Codes_and_Standards/List...
http://tis.eh.doe.gov/techstds/meeting/NRCDOELightningS...
http://www.lightningsafety.com/nlsi_lhm/magic.pdf
etc. for more info
RE: Lightning protection for guyed tower
The tower is not built yet and the design will be completed and reviewed by EE. This was mostly for me to understand.
Once again, I am much obliged to both of you.