JB for DC circuits – Miniature circuit-breakers for DC and solar generation
IEC 60947-2, EN60947-2, GB 14048.2
The JB is a DC circuit breaker dedicated to multi string photovoltaic installations.
This circuit breaker is designed to protect the cables located between each string of photovoltaic modules and the photovoltaic inverter against overloads and short circuits (see application diagram).
Combined with a switch , the JB will be installed in a string PV protection enclosure at the end of each string of photovoltaic modules.
It can be locked (by a padlocking device) in OFF position as a safety measure for removal of the PV inverter.
Since a fault current can flow in the reverse direction to the operating current, the JB can detect and protect against any bidirectional current.
To ensure the safety of the installation, it is necessary, depending on the various types of application, to combine the JB with:
- a residual current device at the AC end,
- a fault passage detector (insulation monitoring device) at the DC end
- an earth protection circuit breaker at the DC end
In all cases, fast action on site will be required to clear the fault (protection not ensured in the event of a double fault).
JB is not polarity sensitive: (+) and (-) wires can inversed without any risk.
The JB is: delivered with three inter-pole barrier to provide increased isolation distance between two adjacent connectors.