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Surge Protection for an Exterior Antenna.

Merry Christmas
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DSoto

Member
I'm trying to put together a design specification for a cellular signal amplifier to be placed in a home. The product contains an exterior antenna that is not grounded, and a lead in conductor goes into the building to an amplifier that is then connected to an indoor antenna. The question was raised about whether or not compliance with Article 810.20 of the NEC even though the following has been said about the device.

"We have never tested the amplifiers to see if using a N connector with a grounding lug will change or effect the performance of the amplifier. We keep the path to the amplifier as clean as possible. We have to worry about external radiated signal as these units have passed both FCC and IC testing. Any other external connection could provide additional radiating paths for the signal which would void our FCC and IC grants.

Somewhere, somebody has to realize that the in building amplifier has an outside antenna, an inside antenna, and the amplifier case. There is no connection of any other type, to the CATV system in a building, electrical system, etc. The only connection we have is from a wall power supply that has a UL rating on it. This power supply converts 120 VAC to 12 VDC to enter the amplifiers independent power supply.

If lightning hits the external antenna, it will most likely destroy the in building amplifier. the AC power supply has internal fuse protection, but would probably be destroyed as well. There are no other connections to any other type of equipment.

I suggested a GFI outlet be mandatory for the amplifier as this would give you shorting and lightning protection to the system, be simple, and everybody can easily get one."​

Just to be safe, I was thinking about simply enclosing the lead in conductors in a continuous metal shield that is effectively grounded. In this way we don't have to worry about affecting the signals going into the amplifier and we are within NEC compliance. Any comments or suggestions?
 

Smart $

Esteemed Member
Location
Ohio
"Just to be safe..." is better than borderline :D

Antennas themselves do not have to be grounded, only masts, metal supporting structures, discharge units, and lead-in shields.
 
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JeanMarie

New member
Fuse Panel

Fuse Panel

I've been told that in our RV, the fuse panel shouldn't be in the same cabinet as the sink, that it's not code compliant. Is this correct, and why? Thanks
 
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