Negative connections

[erosroberts]

I have been informed by several different sources that the only lead you disconnect either in a combiner box or safety switch is the positive lead and the negatives stay connected. Is this information true and if so why ?

 

[iwire]

I have been informed by several different sources that the only lead you disconnect either in a combiner box or safety switch is the positive lead and the negatives stay connected. Is this information true and if so why ?

It depends on if it is a negative grounded system or a positive grounded system.

 

[ggunn]

I have been informed by several different sources that the only lead you disconnect either in a combiner box or safety switch is the positive lead and the negatives stay connected. Is this information true and if so why ?

For most systems this is correct. Most are negatively grounded and for them you only break and fuse the positive connectors. For positively grounded systems you leave the positive connected, and break and fuse the negative. For ungrounded systems you must break and fuse both the negative and positive connectors.

NOTE: An ungrounded array means that neither the positive nor the negative DC conductors are connected to ground. Equipment grounding conductors are still required for all exposed metal parts.

 

[jaggedben]

The NEC also allows both positive and negative to be broken in a disconnect that is accessible only to qualified persons and only used for array maintenance.

 

[ggunn]

The NEC also allows both positive and negative to be broken in a disconnect that is accessible only to qualified persons and only used for array maintenance.

Although it is not typically done.