[Amps] What to do about 'Neutral' in HB amp?

[Jim]

Whats a catch 22?


It really helps if you include the text your replying to.



Thanks, 73, Jim W7RY

On 12/28/2022 4:10 PM, n4is at comcast.net wrote:
> That is a catch 22.
> The NEC for residence is not the same for a Radio Station, and  R56 -
> Standards and Guidelines for Communication Sites. However we have a
> residence and a Radio Station on the same lot.
> Proper ground system for both requirements are very expensive and ignored by
> most of ham stations I visited on my previous antenna business.
> It is not what to do with the neutral only on the 240Vac amplifier, it is
> the RF ground, AC ground and neutral at the residence and at the station.
> The Towers ground has another complication, lighting and RF ground plane.
> Besides the NEC code and R46. The ground for lighting requires a 00 cable
> from the leg of the tower to several ground rod. The ground for RF require
> radials, The ground for NEC requires only one point of connection with the
> AC entrance ground, where the NEUTRAL is connect, and ALL the NEUTRAL must
> be connected to only that single point, next to the AC meter, or AC
> entrance. There is one ground rod there for that.
> Also any rotor cable, control cable and any coaxial cable from the tower
> must be properly grounded in several points.
> All this complexity goes to the station with cables coming from the tower
> into the Amplifier and cables from the amplifier to the AC wire of the house
> including the neutral !
> The solution at my station to comply and be safe with all standards
> requirements was to use a 240Vav  3KW medical isolation transformer for the
> 110AC at the station and the center to the RF ground outside the house. The
> same 240Vac line from the Amplifier and the isolation transformer does not
> use the neutral from the house wiring, but goes to the outside RF ground
> that has a 00 cable and several ground rods with only one connection to the
> Neutral at the AC entrance, the same as the AC outlet on the wall from the
> house wiring. All my cables and from the tower are grounded outside the
> house, inside a large steel galvanized box, grounded on that 00 cable.
> So, the neutral is connected as NEC requires, it is safe and comply with
> r56. The 240 Vac to the station has a larger AC common mode filter with the
> house neutral at the input and only to phases out for the 240 Vac, for the
> amplifier and the isolation transformer, the center of the secondary 110+100
> is the neutral of the station, connected to the house neutral in only one
> point at the entrance of the house. No neutral loop ground!!
>
> If you don't follow all requirements, your station will suffer severer
> damage with any lighting event and the way you connect the neutral to your
> amplifier will means nothing.  Be safe.
>
> 73's
> JC
> N4IS
>
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