Connector Confusion Don't want to mix up polarity

10 Posts
Sep 21, 2009 12:44 pm
Connector Confusion Don't want to mix up polarity

I'm confused. I am wiring two panels in series. I have the panels connected together however I understand I need to wire the two remaining leads, PV Positive to the Positive fuse in the Combiner box and I understand PV Negative lead goes to the PV Negative bus in the Combiner box...however when I split the MC 2 Connector the ends show opposite in polarity, the  markings become opposite to what the leads are on the connection directly from the solar panel.  I hope I'm making the question clear.  If I cut the solarline directly from one of the leads it would be for instance positive, but when I cut the MC 2 Connector that I'm running from the Combiner box it will show as the opposite polarity.  SO...do I ignore the marking on the
lead and just wire as if the solerline was cut?  Or do I wire what it says on the end of the connector?   I don't want to reverse polarity into the box by accident.  I'm sorry I know this should be a no brainier but I don't want to accidentally blow out the panels.
Thanks in advance,
Ann
 
578 Posts
Sep 21, 2009 01:00 pm
Re: 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

AltE
"Making Renewable Do-able"
http://www.altEstore.com/

Tel: 877.878.4060 x107  or +1.978.562.5858 x107
Fax: 877.242.6718  or +1.978.562.5854
 
10 Posts
Sep 21, 2009 02:47 pm
Re: Connector Confusion Don't want to mix up polarity

Thank you James!!!!
Thanks for your quick and clear response.

Ann
 
578 Posts
Sep 21, 2009 03:22 pm
Re: Connector Confusion Don't want to mix up polarity

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

AltE
"Making Renewable Do-able"
http://www.altEstore.com/

Tel: 877.878.4060 x107  or +1.978.562.5858 x107
Fax: 877.242.6718  or +1.978.562.5854
« Last Edit: Sep 21, 2009 03:24 pm by James Cormican »
 
10 Posts
Sep 21, 2009 04:52 pm
Re: Connector Confusion Don't want to mix up polarity

Thanks again!!!
I will make sure I measure voltage from the bottom of the breaker, with the positive multimeter lead to the negative bus bar with the negative lead.
Thanks!!
Ann
 
99 Posts
Sep 25, 2009 09:05 pm
Re: Connector Confusion Don't want to mix up polarity

I had a "professional" install my panels and charge controller... and they installed them with the polarity reversed!  I only discovered it about two weeks later when I found that my batteries were not being charged.  None of the equipment was damaged thankfully.  Kyocera panels and Outback CC.  I diagnosed and fixed the problem myself -- be careful when dealing with contractors.  Ask for references.

 

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