<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; font-size: 14px; font-family: Capitals, sans-serif; "><div><div><div><font class="Apple-style-span" color="#00007f">Mark,</font></div><div><font class="Apple-style-span" color="#00007f">Shorting the string should not be an issue. </font></div><div><font class="Apple-style-span" color="#00007f">Unless you work at night, obviously there will be an arc when you cut the jumper, so remember to cover the whole string with an opaque covering beforehand… I think I remember reading that somewhere?!?! </font></div><div><font class="Apple-style-span" color="#00007f">Or just be careful, try to do it when the irradiance is low (less current), separate the cut wires quickly and make sure you have left enough wire in the box so that you are not working with short (and energized) wires in a metal box. put a wire nut on one wire while you handle and terminate the other.</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">A safer method, if possible, would be to leave an easily accessible module interconnection un-connected until you have terminated the home run (+)&(-), then go back and make the final module interconnection.</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">Cheers,</font></div><div><font class="Apple-style-span" color="#00007f">benn</font></div><div><div><div><font class="Apple-style-span" color="#00007f">DayStar Renewable Energy Inc. </font></div><div><font class="Apple-style-span" color="#00007f">www.daystarsolar.ca * Ph: 780-906-7807 </font></div><div><font class="Apple-style-span" color="#00007f">Construction Electrician Solar Photovoltaic Systems Certified</font></div><div><font class="Apple-style-span" color="#00007f">Certificate # 0007S</font></div><div><font class="Apple-style-span" color="#00007f">HAVE A SUNNY DAY</font></div></div></div></div></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><span id="OLK_SRC_BODY_SECTION"><div><div><font class="Apple-style-span" color="#00007f">On 17/09/12 9:50 PM, "Mark Frye" <<a href="mailto:markf@berkeleysolar.com">markf@berkeleysolar.com</a>> wrote:</font></div></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><div><div><font class="Apple-style-span" color="#00007f">Wrenches,</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">True or False: In a nominal sort of grid tied situation with string Voc </font></div><div><font class="Apple-style-span" color="#00007f">at about 300 VDC and Isc at about 6 or 7 amps......It is OK to install </font></div><div><font class="Apple-style-span" color="#00007f">modules on a roof in the sun and short the pos and neg together </font></div><div><font class="Apple-style-span" color="#00007f">indefinitely.</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">In other words modules can handle operating at Isc continuously without </font></div><div><font class="Apple-style-span" color="#00007f">damage. It is only if you get localized shading AND a failed bypass </font></div><div><font class="Apple-style-span" color="#00007f">diode that damaging hot spot heating can lead to failure?</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">I am reviewing an installation manual that recommends completing the </font></div><div><font class="Apple-style-span" color="#00007f">home run by connecting the pos and neg of the string with a single </font></div><div><font class="Apple-style-span" color="#00007f">jumper cable, folding the cable on itself in order to push it through to </font></div><div><font class="Apple-style-span" color="#00007f">a j-box and at some point later on, cutting the jumper in the j-box to </font></div><div><font class="Apple-style-span" color="#00007f">terminate the pos and negs to the home run.</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">I am concerned both about maintaining the string in a short circuit </font></div><div><font class="Apple-style-span" color="#00007f">condition and cutting the jumper while energized.</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">Any thoughts?</font></div><div><font class="Apple-style-span" color="#00007f"><br></font></div><div><font class="Apple-style-span" color="#00007f">Mark Frye</font></div><div><font class="Apple-style-span" color="#00007f">Berkeley Solar Electric Systems</font></div><div><br></div><div style="color: rgb(0, 0, 255); "><br></div></div></div></span></body></html>