Separately Derived Systems?

[The Iceman]

I was reviewing Mike Holts DVD, Grounding Versus Bonding, about separitely derived systems, and looking at the definition for SDS, and I'm still not 100% sure what a SDS is. I have a good understanding how to ground and bond a SDS. I understand that a generator with a transfer switch that switches the hot and neutral conductors is a SDS. Can anyone explain what a separitely derived system is, or have an example?

 

[iwire]

A standard transformer provides a SDS.

A stack of batteries provides a SDS.

 

[al hildenbrand]

A photovoltaic array

A wind generator

A fuel cell

 

[chris kennedy]

Ice, since your a Florida guy, I'm guessing generators are your issue. Note below the key is no direct connection. For example a 4 pole transfer switch that will switch the grounded conductor.

Separately Derived System. A premises wiring system whose power is derived from a source of electric energy or equipment other than a service. Such systems have no direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.