Number of transfer switches

[frostback]

It is my understanding of the NEC code that outside of a highrise building
if you opt to put lighting on a generator set you must have a circuit breaker at the gen set and a separate transfer switch.Only lighting can be on this
switch.In a highrise situation the transfer switch can also include fire alarm
and communications for fire fighting.Any other loads such as an elevator needs its own transfer switch.Where is a definitive statement in the code
that backs this issue up.Article 700.1 sort of touches on the subject.
We have seen several engineered plans come thru our office with a single transfer switch serving lighting, elevator and other misc. items.
We are a design/build electrical contracting firm and in the past have been required by electrical inspectors to install a separate lighting transfer switch.
Any comments from electrical inspectors or engineers on this topic would be
appreciated,thankyou.

 

[dahualin]

You shall understand the 700 load, 701 load, and 702 load.
700 load: emergency systems are those systems legally required and classed as emergency by municipal, state, federal, or other codes, or by any governmental agency having jurisdiction. In other words, it is life safety related system.
701 load: legally required standby systems are those systems required and so classed as legally required standby by municipal, state, federal, or other codes or by any governmental agency having jurisdiction. In other words, it is very inportant system without life safety concern.
702 load: optional standby systems are those systems intended to supply power to public or private facilities or property where life safety does not depend on the performance of the system.

If you have 700 load and 701 load or 702 load, you shall have two separate ATS for them. But how to define those loads is really vary based on projects. You probably need talk to local AHJ to find out. In general, any system related to life safery such as emergency lighting, fire alarm system, PA system work with fire alarm system, elevators used for egress path etc. shall be 700 load.

Hope this help.