Another 700 vs 701 vs 702 Question

[Lbartowski]

Do I have a good argument that an exterior access control gate arm could and/or should be on the 702 optional standby system? It's not for egress out of a building (however it could be argued that the gate provides access to the rear of a public building for EM response vehicles).

Yes, the EM system is required by law to come online in 10 seconds, but if all of these systems are being supplied from the same generator, don't they typically all come online at the same time? If the generator is sized properly, I'm not sure why they wouldn't all come online at the same time, and if that's the case, is there really any difference between the systems?

Thanks ahead for any responses.

 

[charlie b]

You seem to have two different questions here. To the first, I will say that the NEC 700.2 definition of "emergency systems" basically says that if a governmental authority (e.g., building code) does not say that that load is an "emergency load," then it is not. Your control gate arm would not meet that definition. There is a similar definition in 701.2 about legally required standby loads, and your control gate arm would not meet that definition either. So yes, it is an optional standby load.

Regarding your other question, if you have 700, 701, and 702 loads off the same generator, then they need separate transfer switches. The 700 ATS can't share with the other two, but the other two can share with each other. The 700 loads must be on in 10 seconds. The 701 loads must be on within 60 seconds. There is no time restriction for the 702 loads.

 

[Lbartowski]

Thanks for your reply. Just one more thing. If both ATS' are online in 10 seconds, at that point, aren't they essentially the same system fed from the same generator? I don't see any benefit to using the EM system over the stand-bye system.
Im also arguing that the owners desire to put these new gate units on Art 700 EM is misguided and could result in pushback from the AHJ who makes the decisions regarding what can be considered a 700 load.

 

[charlie b]

The 700 ATS has to be on line within 10 seconds. A 701 ATS has to be on line in 60 seconds. A 702 ATS has no time restriction. But you could have all three, and they all might come on at the same time. The thing to worry about is whether having load on all three start at the same time could overload the generator. That is why they are intentionally staggered in start time.

The problem with a 700 system component (including the ATS) sharing any wiring or conduit or junction box or whatever with a 702 system component is the risk that an unimportant load (such as the gate arm) might get a short circuit, and cause a loss of power to a "real emergency" load (such as an egress light).

But I think your real problem is that the owners speak only one language and you speak two. You both speak what I like to call "conversational English." You also speak the language of our profession. The word "emergency" appears in both languages, but it means two entirely different things. In our language, "emergency" means only what article 700 says it means. To most people, that word means whatever you fall back on when normal things are not working. I keep what I like to call an "emergency $20 bill" in my wallet, in case I find myself at a food truck that does not accept credit cards. Most homeowners and business owners who have a backup generator for their property will call it an "emergency generator." In "conversational English," that is OK. In the language of our profession, that is wrong. This is what you need to explain to the owners. They can put the control gate arm on the generator. But if the facility actually has a 700 system (e.g., for egress lights), the control gate arm cannot be a part of the "emergency power distribution system."