I'm a utility guy and do not own a NEC book . I was in a discussion with a guy pertaining to generator connections to a residence . I was always under the impression that a visible disconnect was required when you isolate your panel and go on generator . I assumed that a disconnect switch was ok but he thinks a molded case breaker ( main breaker ) is an allowable means of isolation . Can somebody straighten me out and give me a place to look if I can find a book ?
Code reference for generator installation .
- Thread starter djohns6
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He also threw this at me . http://www.interlockkit.com/
The interlock kit is permissible as is a breaker or switch.
The particular Code reference would depend on the system (legally required, optional, etc) but an example is:
702.6 Transfer Equipment. Transfer equipment shall be
suitable for the intended use and designed and installed so
as to prevent the inadvertent interconnection of normal and
alternate sources of supply in any operation of the transfer
equipment. Transfer equipment and electric power production
systems installed to permit operation in parallel with
the normal source shall meet the requirements of Article
705 .
The particular Code reference would depend on the system (legally required, optional, etc) but an example is:
702.6 Transfer Equipment. Transfer equipment shall be
suitable for the intended use and designed and installed so
as to prevent the inadvertent interconnection of normal and
alternate sources of supply in any operation of the transfer
equipment. Transfer equipment and electric power production
systems installed to permit operation in parallel with
the normal source shall meet the requirements of Article
705 .
Why is that such a surprise? At a normal house or building without a generator, what do you do to remove power from all circuits -- throw the main breaker(s). Do you think the breaker is going to magically start conducting? As a utility guy, you'd say there is still power in that main panel and in the meter socket. But turning off the main is adequate for most work. Pulling the meter is next (unless its a CT). Finally, you go to the pole or transformer to do a complete disconnect.
Transfer equipment with two breakers just puts a connecting handle between them or that sheet metal sliding interlock. But a breaker is also a switch.
Transfer equipment with two breakers just puts a connecting handle between them or that sheet metal sliding interlock. But a breaker is also a switch.
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- Massachusetts
The only time I have ever seen a requirement for a disconnecting means to have a visible break has been in utility documents for co-generation connections to the grid. Keep in mind this does not apply to back up generators, only co-generation set ups like grid tied PV or wind etc.
You will not find such a requiment in the NEC.
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