Schneider C60H-DC Protector Practical Manual

Schneider C60H-DC Protector Practical Manual

The particularity of DC circuit protection and the positioning of C60H-DC

In the fields of industrial control, transportation (rail transit, electric vehicles), renewable energy (photovoltaics, energy storage), etc., the safe operation of DC distribution systems highly relies on reliable overload and short-circuit protection devices. Unlike AC circuits, DC current does not have a natural zero crossing point, making arc extinguishing more difficult. Therefore, higher requirements are placed on the arc extinguishing and breaking capabilities of circuit breakers. In addition, the grounding methods (equivalent to IT, TN, TT DC) and voltage levels of DC systems are widely distributed, covering from 24V control circuits to 500V photovoltaic arrays. A single specification of protective devices cannot meet all scenarios.

The Schneider Electric C60H-DC series DC supplementary protector is designed to address these challenges. It complies with UL1077, IEC60947-2, EN60947-2, and GB14048.2 multi country standards and can be used as feeder protection, motor control circuit protection, and isolation device simultaneously. This article provides a detailed analysis of the selection rules, installation points, trip characteristics, and fault protection strategies for C60H-DC from an engineering practical perspective.

Product series and selection basis

2.1 Voltage level and number of poles

C60H-DC offers two voltage level series:

12-250V DC series: rated voltage 250V DC, breaking capacity 5kA. Suitable for single pole (1P) or double pole (2P) configurations.

12~500V DC series: Rated voltage of 500V DC, with a breaking capacity of 5kA. Only available in bipolar (2P) configuration.

Each module with a width of 9mm (1P) or 18mm (2P). When selecting, the first step is to determine the nominal voltage (Un) of the system and the maximum possible short-circuit current. If the system voltage is ≤ 250V DC and the short-circuit current is ≤ 5kA, 1P or 2P can be selected; if the voltage is between 250-500V, 2P model must be used, and both poles must be connected in series in the positive and negative circuits at the same time.

2.2 Rated current level

C60H-DC provides complete current levels from 0.5A to 63A, divided into two groups:

0.5A~40A: Suitable for control circuits, electronic loads, low-power DC motors, etc. The specific specifications include 0.5, 1, 2, 3, 4, 5, 6, 10, 13, 15, 16, 20, 25, 30, 32, 40A (UL1077 list) and 50, 63A (IEC list).

50A, 63A: Suitable for higher power DC feeders or combiner boxes.

All rated currents are defined at an ambient temperature of 25 ℃. When the working environment temperature deviates from 25 ℃, adjustments must be made based on the temperature derating curve provided by the manufacturer (module 92515). The general experience is that for every 10 ℃ increase in ambient temperature, the rated current should be reduced by about 5% to 10%, and the specific value should be based on the official derating table.

2.3 Release Curve

C60H-DC only provides the C-curve, which is a thermal magnetic trip characteristic defined in IEC/EN 60947-2. The thermal trip part (overload protection) of the C-curve does not trip within 1 hour at 1.13 times the rated current, and trips within 1 hour at 1.45 times the rated current; The action range of magnetic trip (short circuit protection) is 7-10 times the rated current. The magnetic trip setting value of C60H-DC is marked as 8.5 In (± 20%), which means that the actual operating current is about 6.8-10.2 times the rated current.

The C-curve is very suitable for loads with moderate surge currents, such as small DC motors, solenoid valves, capacitive power supplies, etc. For purely resistive loads or circuits that are insensitive to transient overcurrent, the C-curve can also provide reliable overload protection.

Key rules for installation and wiring

3.1 Polarity Connection - Non Negligible Safety Points

C60H-DC is designed specifically for direct current, and its arc extinguishing system is strongly related to polarity. The polarity indicated on the front of the product must be strictly followed (usually marked with "+" and "-" next to the terminal). Reverse connection can seriously reduce the breaking capacity, which may lead to arc extinguishing failure, contact fusion welding, and even fire in the event of a short circuit fault.

For a 1P protector, the positive pole (L+) is usually connected to the terminal marked with a "+", while the negative pole (L -) can be directly connected through other means or disconnected from both poles using a 2P protector. For 2P protectors, the polarity of each pole has been clearly marked, and the positive pole must be connected to the positive pole marked, and the negative pole must be connected to the negative pole marked.

Special reminder: When two poles are connected in series for use in the US power grid (such as a 60V DC system that requires both poles to be disconnected), in order to avoid inductive interference and ensure reliable disconnection, the length of the connecting cable between the two poles should be at least 30cm (12 inches). This requirement originates from the relevant regulations of the National Electrical Code (NEC) in the United States, with the aim of ensuring that the series poles can withstand the same transient voltage distribution during a short circuit.