Commissioning

List of Checks and Inspections

DANGER

HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E or CSA Z462 or local equivalent. This equipment must only be installed and serviced by qualified electrical personnel. Turn off all power supplying this equipment before working on or inside equipment. Always use a properly rated voltage sensing device to confirm that power is off. Put back all devices, doors, and covers before turning on power to this equipment. Repair the installation immediately if an insulation fault occurs during operation. Failure to follow these instructions will result in death or serious injury.

When starting up new equipment, or following lengthy downtime, a general check takes just a few minutes. Such a check reduces the risk of a malfunction due to error or oversight.

The following table indicates the checks and inspections to be performed according to the event:

A: Insulation and Dielectric Strength Tests

CAUTION
HAZARD OF EQUIPMENT DAMAGE Insulation and dielectric strength tests must only be carried out by qualified electrical personnel. Failure to follow these instructions can result in injury or equipment damage.

Insulation and dielectric strength tests are carried out before the switchboard is delivered. These tests are subject to the currently applicable standards.

These tests must be carried out periodically on photovoltaic 1,000 Vdc applications.

Dielectric strength tests impose great stress on the equipment and can cause damage if performed incorrectly. In particular:

• Reduce the value used for the test voltage according to the number of consecutive tests on the same piece of equipment

• Disconnect electronic equipment if necessary

B: Temperature Rise Tests

ComPacT NSX DC circuit breakers are designed to dissipate the temperature rise produced by the relatively short series of connections of the poles. This is especially important for photovoltaic applications where 4 poles in series (2 poles in series for each polarity) are required to break the rated current or fault current with all poles open at the open-circuit maximum voltage when it is equal to 1,000 Vdc.

Temperature rise tests are carried out before the switchboard is delivered. ComPacT NSX DC circuit breakers comply with product standards IEC 60947-1 and 2.

For general-purpose systems, the tests are carried out with an ambient temperature of 40 °C (104 °F). Above 40 °C (104 °F), overload protection characteristics are slightly modified and values defined in the derating tables must be taken into account. The values are valid for fixed and withdrawable circuit breakers with or without terminal shields.

For photovoltaic applications, the tests are carried out with

• an ambient temperature of 20 °C (68 °F)

• vertical mounting of fixed circuit breakers

• terminal shields (mandatory for all DC photovoltaic circuit breakers with rated voltage above 500 Vdc) heat sinks on top

• 4 cables on the bottom connections with section and length according to IEC 60947-1 Table 9:

  • when used in array boxes, with short connection to string protections, the cross section of the bars or cables must have a higher cross section

  • when cables have a cross section lower than the value indicated in the table, an additional 0.9 derating coefficient must be applied

C: Inspect Switchboard

Check that the circuit breakers are installed:

• In a clean environment without waste from assembling the equipment (such as wiring, tools, shavings, metallic particles)

• In a properly ventilated switchboard (unobstructed ventilation grilles)

D: Check Compliance with the Diagram

Check that the circuit breakers comply with the installation diagram:

• Identification of the feeds on the front of the circuit breakers

• Rating and breaking capacity (shown on the faceplate label)

• Identification of the trip units (type, rating)

• Presence of additional functions (motor mechanism, rotary handle, control or indication auxiliaries, locking, sealing)

• Protection settings: visually check the position of the adjustment dials on the trip unit

E: Inspect Mechanical Equipment

Visually inspect the general state of the circuit breaker. Check the following items:

• Terminal shields and interphase barriers

• Escutcheon

• Trip unit

• Case

• Chassis

Check the equipment integrity: a circuit breaker found with a cracked case or burn marks must be immediately taken out of service and replaced.

Check the mounting and mechanical strength:

• Of circuit breakers in the switchboard, and of power connections and heat sinks (torque: 50 N•m)

• Of auxiliaries and accessories on the circuit breakers:

  • Rotary handles or motor mechanisms

  • Installation accessories (such as terminal shields, interphase barriers, escutcheons)

• Of the chassis (withdrawable circuit breaker)

• Of locks, padlocks, and padlock support tabs

Photovoltaic application operating conditions involve various environmental stresses: wide temperature variations, humidity, and electrical stresses. In order to ensure performances of equipment during all the life cycle of installation, particular attention must be paid to the following:

• Enclosure integrity (double isolation IP level)

• Circuit breaker operating condition and integrity

  • to evaluate if any overheating has occurred

  • to examine circuit breakers for the presence of dust, moisture, and so on.

• Visual check of electrical connections

• Functional test of equipment and auxiliaries

• Insulation monitoring device test

• Insulation resistance test

F: Check Connections

Check the tightening torque of the power connections and auxiliary circuit connections, as described in the instruction sheets.

G: Check Mechanical Operation

Check the circuit breaker mechanical operation:

• Opening, closing and resetting

• Tripping with the push-to-trip button

• Tripping by MN/MX control auxiliaries

• Opening, closing, resetting by motor mechanism in automatic and manual mode

H: Check Trip Units on Devices

Check that the following are working correctly:

• OF, SD or SDE indication contacts

• Wireless indication auxiliaries

I: Check Pairing of Wireless Devices with Gateway or Panel Server

Check that wireless communication with gateway or panel server is working correctly for wireless indication auxiliaries. The LED is blinking green each time data is sent (every 8 hours, or when status changes).

J: Check Communication

Check that the communication via the communication network works correctly. Refer to DOCA0093EN ULP System (IEC Standard) - User Guide

K: Clean Equipment

To avoid dust deposits that can affect the circuit breaker mechanical operation, clean the circuit breakers when performing maintenance:

• For nonmetallic parts: always use a dry cloth. Do not use cleaning products.

• For metallic parts: preferably use a dry cloth. If a cleaning product must be used, do not apply or splash the product onto non-metallic parts.

This operation is especially important for the photovoltaic 1,000 Vdc applications.