New Digital Controllers with Ground Fault Protection

Press Release Summary:

  • Rugged and reliable controllers housed in NEMA 4X fiberglass reinforced and UV resistant polymer enclosure
  • Programmed to trip when leakage current exceeds the specified maximum allowable amount
  • Engineered to control, monitor and maintain the process temperatures of industrial pipes or tanks

Original Press Release:

Emerson Introduces Economical Digital Controllers for Industrial Heat Tracing

Nelson microprocessor-based digital controllers monitor process temperatures for improved safety, energy efficiency and cost savings

Rosemont, Ill. (June 14, 2021) -- Emerson has launched a low-cost upgrade for electrical heat tracing systems with its new Nelson AXPC100-CM-GP and CM-GP microprocessor-based digital controllers, engineered to accurately control, monitor and maintain the process temperatures of industrial pipes or tanks in ordinary (non-hazardous) locations. Ideal for replacing aging electro-mechanical thermostats, the controllers achieve cost savings by eliminating the need for several components with a design that integrates sensor monitoring, ground fault leakage detection, and remote alarm contacts into a single enclosure.

Rugged and reliable, these environmentally hardened controllers are housed in a NEMA 4X fiberglass reinforced, UV resistant polymer enclosure resistant to rain, snow, hose-directed water and windblown dust. Dual-pole heater switching adds to system versatility, making the controllers suitable for heater voltages from 120vac to 277vac. Broad temperature capability of 0° C to 218° C (32° F to 425° F) increases the range of process operations where they can be installed to deliver outstanding performance, safety and energy efficiency.

Two Versions

While the Nelson CM-GP controller comes ready to wall-mount, the AXPC100-CM-GP is configured for direct installation on piping systems. As a stand-alone pipe mounted solution, the AXPC100-CM-GP significantly reduces installation labor and material costs. It employs the field-proven Nelson AX Connection Kit for fast, simple pipe mounting.

As simple to operate as they are to install, both controllers feature a single line, alphanumeric LCD display that enables the use of English language prompts for set point entry and operation for one heat tracing circuit. LED lights indicate whether there is power to the unit, if the heater power is on, along with the current status of alarms. Dry contacts close in the event of an alarm activation, including high or low temperature alarms, sensor failures or ground fault trips, and are conveniently wired to a terminal strip for local or remote use.

Ground Fault Protection

Built-in ground fault leakage detection is a key advantage because it does away with the need for a separate EPD branch circuit breaker and costly manual maintenance checks.

Ground faults typically are the result of damaged or improperly installed heat tracing cables which allow current-carrying conductors, surfaces or parts to be in contact with grounded objects. This type of fault can eventually become serious, resulting in overheating, dangerous fires and shock hazards.

As a standard feature, Nelson AXPC100-CM-GP and CM-GP controllers are programmed to trip when leakage current exceeds the specified maximum allowable amount. By installing the controllers, the end-user brings their heating circuit up to the current requirements for ground fault equipment protection outlined in the National Electrical Code and Canadian Electrical Code.

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‌About Emerson

Emerson (NYSE: EMR), headquartered in St. Louis, Missouri (USA), is a global technology and engineering company providing innovative solutions for customers in industrial, commercial, and residential markets. Our Emerson Automation Solutions business helps process, hybrid, and discrete manufacturers maximize production, protect personnel and the environment while optimizing their energy and operating costs. Our Emerson Commercial & Residential Solutions business helps ensure human comfort and health, protect food quality and safety, advance energy efficiency, and create sustainable infrastructure. For more information visit

Additional Resources

Maya Jordan
T (800) 621-1506

Dan O'Connell
O'Connell Communications
T (708) 363-6118

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