[RE-wrenches] MC4 Y Connectors

[Nathan Stumpff]

Wrenches,

I don't believe this is a correct use. As was already pointed out, the correct size fuse for those two paralleled strings (assuming 60 cell, 230 or so watt module) would likely be 30 A:

Isc = 8.2
82 A * 2 * 1.56 = 25.6 A = 30 A fuse

The max series fuse rating of the module is most likely 15 A. In the setup described below, the remaining four combined strings could certainly feed a fault at above the rating of the panel (15 A) but below the trip rating of the 30 A fuse.

These Y type connectors are only good when there are 2 parallel strings TOTAL, or possibly three for certain SunPower or other modules as was pointed out.

Cheers,
-Nathan

>penobscotsolar at midmaine.com penobscotsolar at midmaine.com <mailto:re-wrenches%40lists.re-wrenches.org?Subject=Re%3A%20%5BRE-wrenches%5D%20MC4%20Y%20Connectors&In-Reply-To=%3Ceddfba3bfc366ba4d3a5ca866c3b6da2.squirrel%40mail.myottmail.com%3E>
>Fri Mar 9 11:23:45 PST 2012
>

>My whole point is that this method is only good when you are paralleling

>two strings, per breaker/fuse, no more. The "Y's" only combine two

>strings. That allows an installer to cut in half the amount of

>fusible/breakered strings in an installation. If you have 10 strings of

>three panels you can parallel two sets of three panel strings five times.

>This is an efficient design approach saving both installer time and the

>customer money while fully protecting the system. It also makes wire

>management much more aesthetically pleasing.

>

>Daryl


--
Nathan J. Stumpff - Actic Sun, LLC
nathan at arcticsun-llc.com<mailto:nathan at arcticsun-llc.com>
Office: 907/457-1297
Cell: 917/992-7577

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