Phil Clements wrote:
> > > Ground and Neutral are the same in the MAIN breaker box - not necessarily
> > > in
> > > all breaker boxes... A branch circuit (probably quite common for
> > > post-construction install of 240V in our shacks) must have the neutral and
> > > ground separated. You should not wire up a device anywhere which requires
> > > neutral (i.e. the neutral is carrying current) to the ground instead of
> > > neutral.
>
> Right on, Bill!
> This subject comes up several times per year, so let me try to draw a mental
> picture for those who are planning 240 volt service into the shack.
>
> The location where the power lines come into the building and terminate in the
> main breaker box is called the "service entrance" by those in the trade. As
> close as possible to this breaker box, ground rod(s) are installed. The ground
> rod should be 8 feet or longer. Do not try to save a few bucks by using cheap
> rods; get a good one like the power companies use. As we will see later, this
> rod plays an important part in the system. It is referred to in the trade as
> the
> "service entrance ground." A good quality wire is run from the breaker box
> ground bus bar ( a long bar with many holes and set screws for installing
> wires)
> to the ground rod. As Bill stated, the difference between a main service panel
> and a sub-panel is that on the main panel the ground bus bar and the neutral
> bus bar (which is insulated from the box) are strapped together by a jumper
> wire. When running romex throughout the building, the white wires go to the
> neutral bus bar, and the bare wires go to the ground bus bar. When installing
> a sub-panel down-line, the ground (un-insulated) bus bar in the sub panel
> is unused. Both the white and bare romex wires are hooked to the neutral bus
> bar.
This is wrong. The neutral and ground are NEVER tied together except at the MAIN
breaker panel.
This is even true when in some installations the main house breaker is outside
and
the distribution panel with all the branch circuit breakers is mounted inside.
The
ground and neutral are NOT connected together even in this panel. They are only
connected together at the outside main circuit breaker.
>
>
> To get 240 volts, a dual breaker is installed in the sub-panel. The black and
> white wires on the romex go to the terminals on the dual breaker, and the
> bare wire hooks to the neutral bus bar. The 240 volt plug and socket in the
> shack are wired so that the black white and green wires coming from the
> amp hook to the black white and bare wires coming from the sub-panel.
This is wrong also. First you never hook a white wire to a hot 220 terminal.
White
ALWAYS goes to the neutral line. If you are running 220 you need a 4 wire line.
They
have RED, Black, White and a bare ground wire. Again the only place the neutral
and
bare ground wires are tied together is in the main breaker panel. The red and
black
wires are the two hot lines from either side of the 220.
The exception to this is sometimes window air conditioners have a 220 line to
them.
Or a pool or well pump that is only 220 volts. In this case they have no need
for a
neutral as they only operate on 220 volts. A three wire line can be used.
Sometimes
a regular romex (black, white and ground wires) is used. The black goes to one
side
of the 220 and the white goes to the other side of the 220. BUT it is marked
with
RED tape at each end to identify it as a hot line. The bare wire is connected
to the
ground buss in the panel and the outlet end of the line goes to the ground pin.
There is no neutral involved in this circuit.
If a neutral is needed a 4 wire line and 4 wire outlet must be used.
>
>
> In an ideal installation, the power, phone, and TV antenna grounds should all
> hook to the service entrance ground, and enter the building at the same place.
> Another "RF Ground" rod(s) should be installed as close as possible to the
> operating
> position in the station, and solid strap, tubing, or wire run from the radio,
> amp,
> tuner and accessories to this rod. I also add several buried radials to this
> rod
> to assist in keeping RF off all the equipment chassis.
>
> (((73)))
> Phil, K5PC
73
Gary K4FMX
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