Is there any NEC code for separate voltage system ?
Let's say I have 24v AC, 220v/380v AC Three Phase, and 36v DC in a building
Is there allowed to have separated Automatic transfer switch for system like this ?
it is also need's to have separated electrical panel ?
24v it's derived from 220v in 220v/380v system, but is have backed up with battery bank and inverter
also 36v DC is sourced from battery bank, and battery bank is charged by 220v AC, also some circuit branch in 220v AC is backed up by battery bank through inverter
That's system is really complicated
24v AC is for control equipments, like contactor coil, etc
36v DC is for smart office and another DC load, also control equiments
220v AC is for main load in office
380v AC is only for HVAC system, and water pump
24v AC and 36v DC is can be assured not exceeds safety limit's for extra low voltage, because is protected by voltage relay and cutted out when exceeds limit (20-26v AC limits for 24v AC system, 34-38v DC for 36v DC system)
It is automatic transfer switch need's to be centralized in NEC ?, can circuit branch have an individual automatic transfer switch ?
Is there any NEC and NFPA codes related to this ?

 

You could consult your local power service company for their input and opinion.
Generally LV does not require any particular adherent to regulation, except cable/wire size and possible voluntary earth grounding etc.
The rest that is over 60v must conform to NFPA70 etc.

 

Differing voltages must ALWAYS be seperated!! The exception is when you use low voltage to control contactors or relays, but even then you want to isolate the two voltages as much as possible and the panels/boxes MUST be labeled to indicate ALL voltages present.

I am having a lot of trouble understanding what you are trying to do exactly. An automatic transfer switch can be placed in almost any configuration. If I wanted redundant supply to a critical piece of equipment then I can put an ATS just before the equipment and protect only the equipment, or I could place it further upstream and protect the entire panel that feeds that equipment(and most probably other equipment each on their own branches as well). I could install an ATS that monitors and switches between two incoming services and feeds the entire building(an approach often used with backup generators). I have servers that have transfer switches built in with multiple power supplies each with their own discrete power cord and provides redundancy to protect against lost power sources, damaged power cables, and damaged power supplies. So the answer to the question 'can circuit branch have an individual automatic transfer switch' would be yes. Codes would depend on what kind of ATS you are using. Some of our ATS's are plug and play devices, It plugs into wall outlets(2 seperate sources) and the devices plug into it. As long as these devices are not modified and used according to mfg specification, then electrical code shouldn't come into play or at least should not be a con. Some ATS's are hardwired devices(like those for backup generators) that must be installed by a licensed electrician and would definitely have related codes you must follow.

In all of this, I can't imagine where low voltage would come into play or have any effect, and any circuit not explicitly relevant to the source/load distribution being managed by the ATS should NEVER appear at that transfer switch. If this doesn't answer your question exactly, give me a better idea of what you are trying to accomplish and perhaps I can provide better information.

Just my personal opinion and no offense intended, but if you are not aware of what codes apply to this, then it sounds like it's time to contract this out or at least consult a licensed electrician. I believe all U.S. jurisdictions require a licensed electrician for projects of this nature in a commercial environment. I personally hate paying someone else to do work that I know I can complete just as well as they could, but the safety and liability aspect is of utmost importance. One very small mistake can cost someone their life!! You don't want that liability to land on you, especially if you don't have a license!

 

In control systems enclosures, LV and HV can be ran in the same raceway or wire duct, the stipulation is that the insulation rating of all conductors shall be rated for the highest voltage conductor.
These voltages can range from 600vac to 5v DC.
In the case of a conductor that is switched from a separate enclosure/source, the conductor shall be Orange in colour.
(N.A. recently changed this particular wire colour from yellow to Orange to conform to EU)

 

I am rather confused, unless the TS is using the NEC as a reference and not aa binding rule book.It is not a wold wide law book.
The NEC does include a lot of useful information but it also seems in places to be protecting the very dumbest people around..

 

I am rather confused, unless the TS is using the NEC as a reference and not aa binding rule book.It is not a wold wide law book.
The NEC does include a lot of useful information but it also seems in places to be protecting the very dumbest people around..

Unfortunately that's the world we live in. As a controls engineer, 90% of my work is "stupid proofing", essentially finding ways to prevent idiots from doing things that make normal people feel stupider for just having heard about it.

 

I am rather confused, unless the TS is using the NEC as a reference and not aa binding rule book.It is not a wold wide law book.
The NEC does include a lot of useful information but it also seems in places to be protecting the very dumbest people around..

Ok... I just want to know about NEC rules...

 

Ok... I just want to know about NEC rules...

Specifically for multi nominal voltage system

 

Specifically for multi nominal voltage system

Yes, then it goes back to Max's post #4. NEC 300.3(C)(1) covers it but pretty much is what Max stated.

Ron