Wiring, Emergency Systems

[flengineer]

NEC 700.9 (B) states that "wiring from an emergency source...to emergency loads shall be kept entirely independent of all other wiring and equipment."

Where does the emergency system wiring begin?

I have a separate emergency service which feeds an ATS also fed by a generator. Is the wiring that comes from the vault to the emergency main considered emergency system wiring, ie, do I need to keep it separate from the "normal" and "optional standby" power feeds coming from the vault?

The Contractor provided a separate pull box for the normal power, but ran the emergency with the optional standby in the same box.

 

[charlie b]

More information is needed. What is in "the vault"? What do youy mean by saying you have a "separate emergency service"?

 

[flengineer]

The vault contains the utility company's transformer.

We have a three mains: one for normal power, one for emergency power and one for optional standby power.

 

[Cavie]

You can have standby generator power with out having and Emergancy power systems. Two differant animals.

 

[flengineer]

We have emergency power and optional standby, two different systems, in addition to normal power.

My question is this: Is the feeder that comes from the utility company and feeds the non-generator side of the ATS considered part of the emergency wiring and therefore must be separated from the "normal" feeder from the utility company?

 

[charlie b]

I consider nothing "emergency," until you get to the transfer switch. So my answer is that the utility feeds into the emergency branch and into the optional standby branch need not be separated.