NEC 700.3

[alixenos]

Hi,

I'm reading 700.3 Tests and maintenance section and it mentions the following:

"If the emergency system relies on a single alternate source of power which will be disabled for maintenance or repair, the emergency system shall include permanent switching means to connect a portable or alternate source of power, which shall be available for the duration of maintenance and repair"

So, I'm providing an emergency generator, which it will be the single alternate source of power. Based on the above, should I provide in my design another transfer switch that will connect to another portable source of power if this generator gets maintained?

Thanks for the help.

 

[qcroanoke]

If it is an article 700 emergency system.
Yes.
And it has to perform as required in 700,12.

 

[charlie b]

This code requirement is relatively new, and I do not yet fully understand it. I see that the switching device must be permanently installed. I see that during maintenance of the emergency generator, a separate power source must be "available." But does it need to comply with all the article 700 requirements (e.g., periodic testing)? Must it start up automatically and be on-line powering all emergency loads within 10 seconds of the loss of normal power? Can you omit this extra switch if you don't anticipate taking the generator off-line for longer than (15 min, or 30 min, or fill in your own guess as to time limit)?

Most importantly, recognizing that all things break sometimes, must we include this extra switch or include a second generator for every new building?