TWO ATSs Required? NEC 700-702.

[ecochra1122002]

Scenario: An building in which we have both legally required loads (IE Emergency Lighting) and optional standby loads (IE receptacles for PCs) on a single alternate standby source (diesel-fueled generator). It appears clear that emergency lighting (when on the generator) is a legally required system. If we also have optional loads (IE receptacles for PCs and any other optional load) on the same system, do we have to have the "legally required" emergency loads on SEPARATE transfer switch from the optional standby loads???

The NEC is does not seem clear on this. NEC 700.6(D) Transfer switch equipment shall only supply "emergency" loads. --- It doesn't say Transfer switch equipment shall only supply "legally required" standby loads . NEC 701.6 states that both legally required standby loads and optional standby loads can be on the same system under a couple of conditions. ---

SO- Per NEC 701, it appears that they can both be on the same ATS if system is sized to handle the load. BUT--Per NEC 700, I'm not certain.

Please-- Any and all interpretations are appreciated.

 

[iwire]

You need a generator supplied with two output breakers, one for Article 700 loads one for Article 702 loads.

Beyond those breakers you need separate transfer switches, panels, raceways etc.

The only 'common' part allowed is the generator itself.