Ground wireless antanna mounts

Status
Not open for further replies.

JdoubleU

Senior Member
On the roof of some buildings there are small steel structures that our welder built for mounting wireless antannas. Do these need to be grounded for lighting protection. Also what is the voltage minimum that would require bonding.
 
For lightning protection - it must be put under a zone of protection or it will be subject to a direct strike.

If it is under a zone and not subject to a direct strike it still may require bonding to the lightning protection system.

  • If the steel antenna frame is connected to the steel frame of the building and the steel frame of the buildng is grounded nothing more may be required.

  • If the steel antenna frame is an isolated (nongrounded) body that is located near a lightning conductor then bonding may be required.

  • If the steel antenna frame is a grounded metal body bonding may be required.

See NFPA 780 Section 4.21 "Bonding of Metal Bodies" for all the details and formulas.
 

JdoubleU

Senior Member
Can you bond it to steel structure? What size of conductor would you use? Where do you find lighting protection in the code.
 
I guess I should have said according to NFPA 780 ....... instead of just referencing it at the end.

The 3 main lightning protection standards in the US are NFPA 780, Lightning Protection Institute (LPI) 175 and UL96A. All vary a little but have been coming closer in the last few years.

If you are meeting one of those standards I may be able to help.
 
For lightning protection - it must be put under a zone of protection or it will be subject to a direct strike.


If it is under a zone and not subject to a direct strike it still may require bonding to the lightning protection system.

  • If the steel antenna frame is connected to the steel frame of the building and the steel frame of the buildng is grounded nothing more may be required.

  • If the steel antenna frame is an isolated (nongrounded) body that is located near a lightning conductor then bonding may be required.

  • If the steel antenna frame is a grounded metal body bonding may be required.
See NFPA 780 Section 4.21 "Bonding of Metal Bodies" for all the details and formulas.


So wireless means that there is no wire connected to it? It is operated by a battery?

If that is the case, you would want the device to be within the protected zone, but not bonded and as far away from the potential path of lightning discharge to the earth - or from earth - as possible.

If it is powered by external power, then you would want to install the power suply wiring with the precautionary measures described above and install surge protection on the line. Carry a separate ground wire but kee the device itself isolated from adjacent metal structures.

...and of course with lightning, always cross your fingers and pray.:grin:
 
Status
Not open for further replies.
Top