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Cutting a Wire

Before you make a splice or a connection on a circuit, consult these tips. They'll help you make a tight, high-contact, low resistance connection.

  • When stripping wires, the only tool you should use is a wire stripper.
  • Only use a crimping tool designed for the type of terminal you are crimping.
  • Use the proper wire nut for the amount and size of wire in the connection.
  • Aluminum wire should not be connected to a receptacle unless it is rated for aluminum conductors. As an alternative, connect an 8" piece of copper wire to the receptacle and wire the nut to the aluminum wire using an anti-oxidant compound.
  • Do not use a butt splice in a conduit run because it can pull apart. Make sure all new splices are accessible for future maintenance.

Thermal Units

All thermal unit specifications are based on the motor and controller being operated in an ambient temperature of 40°C (104°F) or less.


Thermal Unit Selection Guidelines:

  • Determine the motor full-load current rating and service factor.
  • Motor and controller (in same ambient temperature): For 1.15 to 1.25 service factor motors, use 100% of motor full load current for thermal unit selection. For 1.0 service factor motors, use 90% of motor full load current for thermal unit selection.
  • Motor and controller (in different ambient temperature): If the motor ambient temperature is 18°F higher than the motor starter's ambient temperature, derate the full load current value from step 2 by an additional 10%. If the motor ambient temperature is 18°F lower than the motor starter's ambient temperature, increase the full load current value from step 2 by an additional 5%. Use the resultant full load current value for thermal unit selection.
  • Locate the proper thermal unit selection column using the thermal unit code associated with the motor starter.
  • Match the thermal unit code to the starter code on the previous page.
  • Do not exceed the motor starter's amp rating.

View Thermal Units.



Are your panel boards covering up trouble? Use the following checklist annually to catch problems and check circuit breakers that are routinely overlooked in regular preventive maintenance checks. Save money by preventing unexpected repairs.

  • Ensure that all power to the panel is turned off.
  • Remove all covers.
  • Visually check for discoloration of metal, breakers and wire.
  • Tighten all connections.
  • Remove dust and dirt with a clean, dry rag.
  • Exercise the circuit breakers by turning them on and off several times.
  • Keep a maintenance schedule inside the panel door and indicate the inspection date before replacing covers.


Time switches can perform simple, 24-hour to one year repeating controls and sophisticated microprocessor-based controls capable of switching several loads accurately. Save energy and money in the long and short run by using them for equipment switching, signal control, sprinkling and irrigation controls, refrigeration controls, warming ovens and security controls.



Stocking dozens of different fuse types wastes time and money. Reduce inventory costs, decrease risk and save money with Low Peak® fuses.


Low Peak® Fuses—47 Uses In One

By using time-delay Low Peak fuses, you can reduce your fuse inventory as much as 50% while reducing the chance of downtime and injury. Use Low Peak fuses for any application requiring fuses rated 1/10 to 6000A and interrupting ratings through 300,000 amperes. That means 47 different fuse types can be replaced by Low Peaks in the 0-600 ampere range alone (Low Peak fuses are manufactured in most UL fuse categories.).


More Resources

The National Electrical Safety Code® is an excellent source for learning to keep people safe during the installation, operation and maintenance of electric supply and communication lines.

The Occupational Safety and Health Administration creates standards and laws for safety in dealing with electricity.

Safety Online is a resource for professionals in the safety industry. It contains information on manufacturing, equipment supplies and emergency response, protective equipment and more.

TECO Energy, Inc. offers the National Electrical Safety Foundation's tips for checking electric cords, appliances and outlets to help prevent electricity-related problems in everyday situations.