The HotLine Internal Pipe Heater is one of the most economical pipe-freeze protection devices on the market. The average U.S. KWH cost is just $0.1209 per kilowatt hour (as of January 2014).
The design of the HotLine Internal Pipe Heater presents a much safer alternative to the traditional mineral filled-in pipe heating elements that operate on 120 or 240 Volts (V) of Alternating Current (AC).
Instead, the HotLine Internal Pipe Heater heating element operates from a safe voltage of 6, 12, 16, 24, or 32 Volt AC transformers depending upon the length of the selected heating element. Note that these are similar voltages used by the most common model railroad trains.
The HotLine Internal Pipe Heater heating element consists of a heavy gauge wire. The wire is made of a modern resistance alloy. It is encased in a 1/4 inch diameter copper or 5/16 inch plastic tube. At a design power of 3 to 7 watts/foot and element lengths from 6 to 100 feet, the shortest HotLine can dissipate from approximately 18 to 42 watts while the longest can dissipate from approximately 300 to 700 watts.
At 3 watts/foot, the temperature of the heating element rises to approximately 100° F. Note that this is only 1.4° higher than normal human body temperature.
Depending upon the length of the heating element, the HotLine Internal Pipe Heater power center provides Class 1 Power-Limited Circuits of 25 Volt/Amps (VA) to 750 VA for the selected HotLine Internal Pipe Heater heating element per the definitions and requirements of applicable articles of the National Electric Code (NEC) Latest Edition.
The power center consists of a Underwriters Laboratory (UL) approved metal-enclosed power center box with its 120 Volt primary protected by a UL recognized fuse holder and fuse. The fusing for each of the different power center boxes is per the applicable articles of the NEC Latest Edition. The top of the power center box gets to 176° F.
An approved and recognized cord with grounded plug is provided with the power center box.
The HotLine power center box is connected to the HotLine internal pipe heating element with a provided UL approved/recognized heavy duty cord. The connection to the heating element is made in a provided PVC Conduit body (LB). These connections are offset from each other to prevent short circuiting.
Jerry B. Hoffer
BSEE, Purdue University, 1961
HotLine Internal Pipe Heater Electrical Consultant