There are several marking and labeling requirements for proper installation of a renewable energy system. Moreover, this is an area of the industry that we feel has not been adequately communicated to the public. This is why we have assigned a specific page just for this very important area of system design and installation.
Marking your system does two critical things:
Identifies the presence of a parallel electrical system - Critical for letting people unfamiliar with your system (utility workers, emergency response personell) know "at-a-glance" how to quickly and safely turn off the power when needed.
Enables the user, designer or installer to install the system, assess the performance of the system and make changes to the system safely.
Allows the inspector to verify proper conductor ampacity and overcurrent device ratings.
Photovoltaic Output Circuit Label:
A permanent label shall be placed at the disconnect switch for the photovoltaic output circuit. Rule 50-004 (1) states that the label must show the following information:
Rated operating current and voltage; and
Rated open-circuit voltage; and
Rated short-circuit current.
This marking should be permanent sign or label which is afixed to the enclosure which contains the disconnect for the PV array. This disconnect could be located in the inverter for interconnected systems (direct grid tie), or housed with other DC disconnects in a central control center in a stand-alone or parallel system.
The example to the right shows a simple, label layout that will satisfy the code requirement for a photovoltaic output circuit label.
Example Solar Photovoltaic System
Rated Open Circuit Voltage
Rated Short Circuit Current
Power Conditioning Unit Label:
Rule 50-004 (2) specifies a permanent label shall be placed at a visible location on the power conditioning unit (inverter) showing the following:
Rated maximum operating current, and
Rated maximum operating voltage, and
DC or AC (frequency)
Warning Notice and Diagram:
Rule 84-032(a,b) deals with utility interconnected systems, and requires the following labels be installed in a conspicuous place at the service entrance (typically on the utility meter base) and at each generator location:
Warning notice of a parallel system, and
A single line, permanent, legible diagram of the switching arrangement to indicate the location of all generators of a parallel system, the interlocks with their function, and the isolation points.
We recommend that warning labels go on the meter base, main disconnect panel, any sub panels, disconnects, power panels and even on the entrances to all buildings serviced by the parallel system.
Rule 84-026(i) identifies the need for the disconnecting means in an interconnected system to have a warning identifying the fact that the inside wiring and parts of the disconnect can be energized when the disconnecting means are open. This ensures that service personel are aware that the supply wires may be energized.