Here we will try to mention how much we label and what we label or what is the content of our labels in order to comply to NEC code and regulations and not to exceed standard requirements. First the material we use for labels has to be special, has to sustain UV, water and weather stress conditions. Most of time that reflects in quality of ink and the fact labels are special laminated for this type of purpose.  What we have to label is of most importance. Generally we label both sections of our installation on DC site as well on AC site. On DC site we have to label the connectors along the rails where PV panels are mounted. One of the label type used with MC connectors is looking like in the picture bellow: 

Another type of labels are used to identify the string or array main I-V characteristics and respective peak power values in accord to NEC regulations. Such labels are more likely to be attached on string or array combiner box, or on the box lid fixed to the system and they haver to be placed very visible. All of this are generic system rating labels on the DC site.

Toghether with this type of labels in order to identify the cable polarity we can use labels to make sure which is the right polarity of that cable.

On DC site we have to rate the charge controllers if any, and we will use a very similar label as in the picture bellow:

The conduit used to lower the home runs to DC disconnect has to be at least once labeled and that requests a label similar to:

Very important! Based on NFPA requirements a big visible label has to specific indicate that this is the main disconnect for the solar panel installation on the DC site.

There are some solar PV  installations with more as a single disconnect depending of the array size. NEC code may require to have for each array a dc disconnect additional to the main dc disconnect.

 

All the dc disconnects are to be labeled and the type of labels are very similar to:

We have to label the inverter on dc site with a label specifying the system inverter ratting values:

 On the AC Site we label the distribution board to make all the operators aware that we run a double power source: AC and DC power source, and we clearly mark the breaker where the invertor is connected.  

In this article we have used Tyco solar labels systems from Tyco Electronics, available at CelanEnergyBrands in NEC Compliant Safety Lables section.