Type I – 70kW Heat tracing panelboard.
General Requirements
Electric heat tracing panel, proposed for piping freezing protection, to be installed in outdoor facilities. Each
heat tracing circuit must be able to allow the system to operate automatically in conjunction with an external
controller thermostat.
1. Enclosure features:
1.1. Wall-mounted type, IP65, class II (IEC60228), UV protection, furnished with glassed main door and
internal door. Panelboard size must be defined by the vendor based on the number and type of CB
(Circuit Breaker) required. It must be taken into consideration a 35% of additional spare volume, same
consideration must be followed with the internal door.
2. Utility features:
Voltage: 3P+N+PE, 400-230Vac, 50Hz.
Grounding system: TNS.
3. Internal configuration:
3.1. Main breaker rating: 4x150A, SC (Short Circuit) capacity 35kA, with LSIG adjustable protections, and four
auxiliaries contacts 2NO + 2NC all of them connected at a control terminal box.
3.2. Downstream the main CB (Circuit Breaker) must be connected to a contactor 4x125A, AC-1, coil voltage
220Vac, 50Hz. Including an auxiliary contact block with 2NO+2NC contacts
3.3. Output feeder circuit breakers: fitted with 2x25A MCB, 10kA, C curve, plus 2x25A RCD, 30mA, both
connected in series. Each set of MCB and RCD must be supplied with low and cero current capabilities.
Number of breakers 7.
3.4. Copper PE bus bar connection, with a minimum cross section of 35mm2. Considering 35% of additional
spare connections.
3.5. The whole output power connections must be available in terminal boxes, minimum size will be 35mm2.
4. Internal door assemblies:
4.1. Main CB (Circuit Breaker) linked by door disconnect handle.
4.2. Hand/Off/Auto switch, and contactor-energize pilot light, following the pattern mentioned in section 4.4
with exception of low current alarm signal.
4.3. Each heat tracing circuit must be supplied with signal LED pilot lights, plastic type, 22mm of diameter,
colors and functions are described at the following point.
4.4. Pilot lights indicator colors and functions.
COLOR
GREEN
RED
WHITE
INDICATION
Heat Tracing ON
Heat Tracing OFF
Low Current Alarm
YELLOW
General Fault
DESCRIPTION
Heat tracing circuit is working properly
Heat tracing circuit is turned off
Low status alarm signal
Heat tracing circuit in general fault condition
(cero current trip + RCD trip + MCB trip)
5. Miscellaneous features:
5.1. Incoming power cables will be installed from the bottom of the panelboard.
5.2. The whole electrical distribution elements, such as distribution bus bars, and interconnection cables must
be designed to support the current rated current of the incoming electrical device. It must consider a 35%
of spare connection points in the electrical distribution elements.
5.3. It is a preference for all electrical devices to be Schneider Electric Brand if possible.
5.4. The vendor will be responsible for the electrical design to support the inrush current with heat tracing
circuits to avoid unnecessaries circuit breaker trips.
5.5. Temperature control method adopted will be line sensing type, by the implementation of thermostats or
electronic controllers to be assembled mechanically in each pipe section to be heated.
5.6. The main contactor can be powered up by an ambient sensing thermostat (mounted remotely), and/or
electronic controller, and/or snow sensor controller, and/or any device with a contact that changes state
when the heat tracing is energized.
5.7. The vendor will be responsible of the electrical devices selection to guarantee a proper selectivity
protection scheme.
Type II – 50kW Heat tracing panelboard.
The same requirements as mentioned above apply, apart from Section 3 that is described below in section 6.
6. Internal configuration:
6.1. Main breaker rating: 4x100A, SC capacity 35kA, with LSIG adjustable protections, and four auxiliaries
contacts 2NO + 2NC all of them connected at a control terminal box.
6.2. Downstream the main CB must be connected a contactor 4x125A, AC-1, coil voltage 220Vac, 50Hz.
Including an auxiliary contact block with 2NO+2NC contacts
6.3. Output circuit breakers: fitted with 2x25A MCB, 10kA, C curve, plus 2x25A RCD, 30mA, both ones
connected in cascade. Each one set of MCB and RCD must be supplied with low and cero current
capabilities. Number of breakers 5.
6.4. Cooper PE bus bar connection, with a minimum cross section of 35mm2. Considering 35% of additional
spare connections.
6.5. The whole output power connections must be available in terminal boxes, minimum size will be 35mm2.