Electrical Data

Electrical Service Sizing

To correctly size electrical service wiring for your unit, find the appropriate calculations listed below. Each type of unit has its own set of calculations for MCA (Minimum Circuit Ampacity), MOP (Maximum Overcurrent Protection), and RDE (Recommended Dual Element fuse size). Read the load definitions that follow and then find the appropriate set of calculations based on your unit type.

Set 1 is for cooling only and cooling with gas heat units, and set 2 is for cooling with electric heat units.

Load Definitions: (To determine load values, see the Electrical Service Sizing DataTables on the following page.)

LOAD1 = CURRENT OFTHE LARGEST MOTOR (COMPRESSOR OR FAN MOTOR)

LOAD2 = SUM OFTHE CURRENTS OF ALL REMAINING MOTORS

LOAD3 = CURRENT OF ELECTRIC HEATERS

LOAD4 = ANY OTHER LOAD RATED AT 1 AMP OR MORE

Set 1. Cooling Only Rooftop Units and Cooling with Gas Heat Rooftop Units

MCA = (1.25 x LOAD1) + LOAD2 + LOAD4

MOP = (2.25 x LOAD1) + LOAD2 + LOAD4

Select a fuse rating equal to the MOP value. If the MOP value does not equal a standard fuse size as listed in NEC 240-6, select the next lower standard fuse rating. NOTE: If selected MOP is less than the MCA, then reselect the lowest standard maximum fuse size which is equal to or larger than the MCA, provided the reselected fuse size does not exceed 800 amps.

RDE = (1.5 x LOAD1) + LOAD2 + LOAD4

Select a fuse rating equal to the RDE value. If the RDE value does not equal a standard fuse size as listed in NEC 240-6, select the next higher standard fuse rating. NOTE: If the selected RDE is greater than the selected MOP value,

then reselect the RDE value to equal the MOP value.

Set 2. Rooftop units with Electric Heat

a. Single Source Power (380V, 415V, 460V, and 575V)

To arrive at the correct MCA, MOP, and RDE values for these units, you must perform two sets of calculations. First calculate the MCA, MOP, and RDE values as if the unit was in cooling mode (use the equations given in Set 1).Then calculate the MCA, MOP, and RDE values as if the unit were in the heating mode as follows.

(Keep in mind when determining LOADS that the compressors don’t run while the unit is in the heating mode).

For units using heaters less than 50 kw.

MCA = 1.25 x (LOAD1 + LOAD2 + LOAD4) + (1.25 x LOAD3)

For units using heaters equal to or greater than 50 kw.

MCA = 1.25 x (LOAD1 + LOAD2 + LOAD4) + LOAD3

The nameplate MCA value will be the larger of the cooling mode MCA value or the heating mode MCA value calculated above.

MOP = (2.25 x LOAD1) + LOAD2 + LOAD3 + LOAD4

The selection MOP value will be the larger of the cooling mode MOP value or the heating mode MOP value calculated above.

Select a fuse rating equal to the MOP value. If the MOP value does not equal a standard fuse size as listed in NEC 240-6, select the next lower standard fuse rating. NOTE: If selected MOP is less than the MCA, then reselect the lowest standard maximum fuse size which is equal to or larger than the MCA, provided the reselected fuse size does not exceed 800 amps.

RDE = (1.5 x LOAD1) + LOAD2 + LOAD3 + LOAD4

The selection RDE value will be the larger of the cooling mode RDE value or the heating mode RDE value calculated above.

Select a fuse rating equal to the RDE value. If the RDE value does not equal a standard fuse size as listed in NEC 240-6, select the next higher standard fuse rating. NOTE: If the selected RDE is greater than the selected MOP value, then reselect the RDE value to equal the MOP value.

b. Dual Source Power units (200V and 230V)

These units will have two circuit values shown on the nameplate.The first circuit value will be the refrigeration (cooling mode) values calculated per Set 1.The second set of circuit values shown on the nameplate will be for the electric heating circuit as follows.

MCA = (1.25 x LOAD3) MOP = (1.25 x LOAD3)

Select a fuse rating for the electric heating circuit that’s equal to the MOP value obtained in the equation above. If the MOP value does not equal a standard fuse size as listed in NEC 240-6, select the next lower standard fuse rating (see note below for exception).

NOTE: If selected MOP is less than the MCA obtained in the equation above, then reselect the lowest standard maximum fuse size which is equal to or larger than the MCA, provided the reselected fuse size does not exceed 800 amps.

RDE = LOAD3

Select a fuse rating for the electric heating circuit that’s equal to the RDE value. If the RDE value does not equal a standard fuse size as listed in NEC 240-6, select the next higher standard fuse rating. NOTE: If the selected RDE is greater than the selected MOP value, then reselect the RDE value to equal the MOP value.

GENERAL NOTES:

On 20 to 130 ton rooftops, the selected MOP value is stamped in the MOP field on the nameplate.

RT-PRC010-EN

83

Page 82 Page 84
Page 83
Image 83
Trane RT-PRC010-EN manual Electrical Data, Electrical Service Sizing, Set 2. Rooftop units with Electric Heat
Page 82 Page 84

RT-PRC010-EN specifications

The Trane RT-PRC010-EN is a prominent model in the line of Trane's packaged rooftop units, designed to offer efficient heating, cooling, and ventilation for commercial applications. Renowned for its robust performance, this unit integrates advanced technologies and superior engineering to meet diverse environmental needs while ensuring energy efficiency and reliability.

One of the key features of the RT-PRC010-EN is its energy-efficient operation. The unit is equipped with variable-speed fans and scroll compressors, which allow for precise control over temperature and airflow. This adaptability not only enhances comfort but also contributes to significant energy savings. The inclusion of high-efficiency cooling coils further optimizes performance, making it an excellent choice for businesses looking to lower their operational costs.

The RT-PRC010-EN model integrates smart controls that allow for seamless integration into building management systems. These controls facilitate real-time monitoring and diagnostics, enabling facility managers to maintain optimum operational efficiency and promptly address any maintenance needs. This technology minimizes downtime and extends the lifecycle of the unit.

Moreover, the unit’s construction is targeted toward resilience and durability. Built with a corrosion-resistant cabinet and extensive insulation, the RT-PRC010-EN can withstand the rigors of various climates, making it suitable for installation across different geographical locations. Its compact design allows for easy installation on rooftops, maximizing space utilization in commercial buildings.

Another standout characteristic is the unit's versatility in application. The RT-PRC010-EN can be tailored to suit a wide range of commercial settings, including retail establishments, educational institutions, and healthcare facilities. Options for various indoor and outdoor configurations enhance its adaptability to specific operational requirements.

In conclusion, the Trane RT-PRC010-EN stands out as an energy-efficient, reliable, and versatile solution for commercial heating and cooling needs. Its advanced features, smart controls, and robust design make it an ideal choice for businesses looking to enhance comfort while minimizing energy expenditures and ensuring operational reliability. Whether dealing with extreme weather conditions or managing indoor air quality concerns, this rooftop unit provides a comprehensive solution tailored to modern commercial requirements.
Top Page Image Contents