Franklin 2007 ユーザーズマニュアル

The primary purpose of grounding the metal drop pipe 
and/or metal well casing in an installation is safety. It is 
done to limit the voltage between nonelectrical (exposed 
metal) parts of the system and ground, thus minimizing 
dangerous shock hazards. Using wire at least the size of 
the motor cable wires provides adequate current-carrying 
capability for any ground fault that might occur. It also 
provides a low resistance path to ground, ensuring that 
the current to ground will be large enough to trip any 
overcurrent device designed to detect faults (such as a 
ground fault circuit interrupter, or GFCI). 

Normally, the ground wire to the motor would provide the 

Franklin Electric control boxes meet UL requirements for 
NEMA Type 3R enclosures. They are suitable for indoor 
and outdoor applications within temperatures of +14 °F 
(-10 °C) to 122 °F (50 °C). Operating control boxes below 
+14 °F can cause reduced starting torque and loss of 
overload protection when overloads are located in 
control boxes. 

Control boxes and panels should never be mounted in 
direct sunlight or high temperature locations. This will 
cause shortened capacitor life and unnecessary tripping 

of overload protectors. A ventilated enclosure painted 
white to refl ect heat is recommended for an outdoor, high 
temperature location.

A damp well pit, or other humid location, accelerates 
component failure from corrosion.

Control boxes with voltage relays are designed for 
vertical upright mounting only. Mounting in other 
positions will affect the operation of the relay.

Allowable motor temperature is based on atmospheric 
pressure or higher surrounding the motor. “Drawdown 
seals,” which seal the well to the pump above its intake 

An above ground surge arrestor must be grounded, 
metal to metal, all the way to the lowest draw down water 
strata for the surge arrestor to be effective. GROUNDING 
THE ARRESTOR TO THE SUPPLY GROUND OR TO 
A DRIVEN GROUND ROD PROVIDES LITTLE OR NO 
SURGE PROTECTION FOR THE MOTOR.

to maximize delivery, are not recommended, since the 
suction created can be lower than atmospheric pressure.

primary path back to the power supply ground for any 
ground fault. There are conditions, however, where the 
ground wire connection could become compromised. 
One such example would be the case where the water 
in the well is abnormally corrosive or aggressive. In this 
example, a grounded metal drop pipe or casing would 
then become the primary path to ground. However, 
the many installations that now use plastic drop pipes 
and/or casings require further steps to be taken for 
safety purposes, so that the water column itself does not 
become the conductive path to ground.

When an installation has abnormally corrosive water 
AND the drop pipe or casing is plastic, Franklin Electric 
recommends the use of a GFCI with a 10 mA set-point. 
In this case, the motor ground wire should be routed 
through the current-sensing device along with the motor 
power leads. Wired this way, the GFCI will trip only when 
a ground fault has occurred AND the motor ground wire 
is no longer functional. 

WARNING: Serious or fatal electrical shock may 
result from failure to connect the motor, control 
enclosures, metal plumbing and all other metal 
near the motor or cable to the power supply ground 
terminal using wire no smaller than motor cable wires.

WARNING: Failure to ground the control frame can 
result in a serious or fatal electrical shock hazard.

The National Electrical Code requires that the control box 
or panel-grounding terminal always be connected to supply 
ground. If the circuit has no grounding conductor and no 
metal conduit from the box to supply panel, use a wire at 
least as large as line conductors and connect as required 
by the National Electrical Code, from the grounding terminal 
to the electrical supply ground.

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