Ingersoll-Rand Thermo King SGCM 4000, Maintenance Manual, Page: 14 / 181

Safety Precautions
13
Low Voltage
Control circuits are low voltage (12 Vdc). This voltage potential is not considered dangerous, but the
large amount of current available (over 30 amperes) can cause severe burns if shorted to ground.
Disconnect the negative terminal of the battery if possible when working on the generator set. Disconnect
the cable end that is away from the battery.
Do not wear jewelry, watches or rings. These items can short out and cause severe bums to the wearer.
The source of shock must be immediately removed by either shutting down the power or removing the
victim from the source. If it is not possible to shut off the power, the wire should be cut with either an
insulated instrument (e.g., a wooden handled axe or cable cutters with heavy insulated handles) or by a
rescuer wearing electrically insulated gloves and safety glasses. Whichever method is used, do not look at
the wire while it is being cut. The ensuing flash can cause burns and blindness.
If the victim has to be removed from a live circuit, pull the victim off with a non-conductive material. Use
the victim’s coat, a rope, wood, or loop your belt around the victim’s leg or arm and pull the victim off.
DO NOT TOUCH the victim. You can receive a shock from current flowing through the victim’s body.
After separating the victim from the power source, check immediately for the presence of a pulse and
respiration. If a pulse is not present, start CPR (Cardio Pulmonary Resuscitation) and call for emergency
medical assistance. If a pulse is present, respiration may be restored by using mouth-to- mouth
resuscitation, but call for emergency medical assistance.
General Safety Precautions for Servicing Units (or Containers)
Equipped with a Microprocessor Controller
Precautions must be taken to prevent electrostatic discharge during service of the SG+ microprocessor
controller and related components. The risk of significant damage to the electronic components of the unit
is possible If these precautionary measures are not followed.
The primary risk potential results are as follows:
• The failure to wear adequate electrostatic discharge preventive equipment when handling and
servicing the controller.
• Electric welding on the unit and/or container chassis without taking precautionary steps.
Controller Repair
It’s necessary to ensure that electrostatic discharges are avoided when servicing the controller. Potential
differences considerably lower than those which produce a small spark from a finger to a door knob can
severely damage or destroy solid-state integrated circuit components. The following procedures must be
rigidly adhered to when servicing these units to avoid controller damage or destruction.
1. Turn the generator set OFF.
2. Disconnect the negative terminal of the battery. Disconnect the cable end that is away from the
battery.
3. Avoid wearing clothing that generates static electricity (wool, nylon, polyester, etc.).
4. Wear a static discharge wrist strap (TK P/N 204-622) with the lead end connected to the controller's
ground terminal. These straps are available at most electronic equipment distributors. DO NOT wear
these straps with power applied to the unit.
5. Avoid contacting the electronic components on the unit circuit boards.