La Marche TPSD - Enabling;Disabling Ground Detection; Figure 13 - Digital Control Card S2 A-341 S (Back View)

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2.8 Enabling/Disabling Ground Detection
The purpose of ground detection is to determine if the battery or loads have become grounded. Ground
detection is available on TPSD units. If the battery or loads are set up as floating, it is recommended that
ground detection be enabled. When ground detection is enabled a positive or negative ground fault indicator
will energize upon detection of a ground. The ground detection circuitry monitors amount of ground current,
and whether it is positive of negative. The ground detection circuitry will alarm when the average threshold of
1.5mA is reached. It is important to realize that La Marche Mfg. Co. is primarily a manufacturer of battery
chargers, and not ground detection systems. If a more precision system is needed, many systems that are
designed specifically for ground detection are compatible with the La Marche battery chargers.
If the battery or loads are either positively or negatively grounded, it is recommended that ground detection be
disabled. If the system is know to be grounded and the ground detection is enabled, the charger will show a
ground fault at all times.
Ground Detection Procedure
Before making any changes to the TPSD ensure that the AC Power is off at the main breaker box and that both
of the units’ breakers are off. To enable or disable ground detection, first locate the S2A-341S card inside the
unit. Refer to Figure 13; all jumpers are located on the back of the card.
Figure 13
–
Digital Control Card S2
A
-341S (Bac
k
V
iew)
T
o ENABLE Ground Detection:
 Place jumper JP5
 Move jumper JP76/JP77 to JP76 position
 Move jumper JP78/JP79 to JP78 position
T
o DISABLE Ground Detection:
 Remove jumper JP5
 Move JP76/JP77 to JP77 position
 Move JP78/JP79 to JP79 position