[RE-wrenches] Short Circuit Cell Damage

[Mark Frye]

Wrenches,

True or False: In a nominal sort of grid tied situation with string Voc 
at about 300 VDC and Isc at about 6 or 7 amps......It is OK to install 
modules on a roof in the sun and short the pos and neg together 
indefinitely.

In other words modules can handle operating at Isc continuously without 
damage. It is only if you get localized shading AND a failed bypass 
diode that damaging hot spot heating can lead to failure?

I am reviewing an installation manual that recommends completing the 
home run by connecting the pos and neg of the string with a single 
jumper cable, folding the cable on itself in order to push it through to 
a j-box and at some point later on, cutting the jumper in the j-box to 
terminate the pos and negs to the home run.

I am concerned both about maintaining the string in a short circuit 
condition and cutting the jumper while energized.

Any thoughts?

Mark Frye
Berkeley Solar Electric Systems