King Electric GPT 3 - Manual (Page 11)

Page 11 of 21
Location
The GPT–3 is suitable for indoor or outdoor mounting on a vertical surface. Although the
NEMA 3R rated housing is strong and durable, choose a protected location for an extra safety
margin. Always consider the possibilities of tampering and vandalism when choosing a location.
Keep the GPT–3 and the heat cable as close together as is practical to minimize installation
costs. There is a 2,000’ (610m) limit on temperature sensor extension wiring.
Figure 1 shows mechanical dimensions of the GPT–3. Note the location of the
compartment provided for low voltage Class 2 connections.
Supply and Heater Connections
The GPT–3 operates from 120, 208, 240 or 277 volts which it automatically selects. The
heaters and GPT–3 operate from the same supply voltage.
The definite purpose DPST heater control contactor is rated for up to 30 AMP loads at 277
volts or less.
Make the supply voltage and heater connections in the compartment provided for this
purpose. See Figure 1.
Use only copper wire for supply, heater and safety ground connections. Select a minimum
GPT ® –3
TRACON ®
GFEP
FAULT SUPPLY
HEATER
GFEP
RESET
TEST
HEATER
FAULT
Temperature
20
15
68
59
25 77
10
5
50
41 °C
°F
We Manage Heat ®
http://www.networketi.com e-mail: [email protected]
®
J1
Heater Shield
Ground
Neutral/L2
Ground
Line/L1
From 120, 208,
240, or 277 VAC
Supply
Equipment
Safety
Ground
To Heater
30 Amp Load Max.
Figure 2. GPT–3 wiring diagram