Connector Confusion Don't want to mix up polarity

no problem, this happens all the time.

1. watch this video
http://www.altestore.com/video/video-MC-Connector-Extensions-Primer-v6/

2.  leave all breakers in the off position, and leave the series connections for LAST

2. land the bare wire ends to the combiner FIRST so you are not dealing with live current.

3.  use RED tape on the MODULE end MC CONNECTOR with the positive embossed on it.  ANYTHING connected to it that is NOT a series connection MUST ALSO BE LABLED RED.  the connector that will mate to that red end will have a negative on it, but it is the only end that will plug in.  REMEMBER to relable this RED right behind the connector, and also on the outside and inside of the combiner box for the bare end.

4. do the same with the negative end of the series string.  label the connector on the module with white tape, and label right behind the connector extension that connects to it with white tape.  do the same labeling for outside and inside of the combiner. when you do this, put the wire through the stain relief on the combiner first, then relabel with tape on outside and inside, otherwise the tape often gets stuck in the strain relief.

if possible cover the modules with the most opaque thing you can find (the boxes may come in handy here).  remember to leave all circuit breakers off.  make your series connection  last, do the extensions first, so that the last connection you make at the array is the final series connection, with all other breakers in the system off.

if everything checks  at the array and where the balance of system stuff is,you can remove the covering then you can turn on the combiner breakers (if you have any), so long as your PV disconnect breaker is OFF.  if you do not have a combiner, then you must leave the pv to controller breaker off for now. 

if you have a battery based system, turn on the charge controller disconnect, that connects the batteries to the charge controller. 

then turn on the pv to controller breaker, and the controller should wake up and show charging current.

james
altE staff

no problem.  just to clarify, always use the polarity that is indicated on the module, not the extension.  tape the conductor of the extension to match the color/polarity of the module end it is attached to.

if you would have wired in reverse polarity, it likely would have been the charge controller, not the modules that would have been destroyed.  either way, something to avoid.

the other thing i did not mention is to test voltage with a multimeter at the combiner (set it to 200vdc which is common on $30 multimeters)  Make sure it is set to voltage!!.  with respect to the multimeter, with red as positive, and black as negative, you should see a positive voltage when connected to the red and white respectively when measuring from the bottom of the breaker(s) (on most combiners) to the negative busbar.  if you see a negative voltage that means you have reverse polarity and should check all connections before turning on any disconnects.

james
altE staff