Generator wiring/Normal power in same conduit

[PaulEd]

Hello ya’ll

Can you combine the branch circuit wiring from a services normal power with that of the wiring from a panel that is back up by a generator?

My thought process is that although they receive their power from the same service under normal conditions if the emergency generator is turned on for the “emergency” panel theoretically you could have live conductors in the same conduit from different separately derived systems

This is a commercial building Not residential

Thoughts?

 

[tom baker]

What type of installation is the generator? Art 700, 701 or 702? It’s not likely this is an emergency source, but if so the load wiring is kept separate from all non emergency wiring.

 

[hillbilly1]

The feeder from the service disconnect? Yes unless it is prohibited by one of the articles Tom posted. But line side of the service disconnect, no.

 

[kwired]

The feeder from the service disconnect? Yes unless it is prohibited by one of the articles Tom posted. But line side of the service disconnect, no.

I approve this message

The conductors in question can be in same enclosures, but service conductors as a general rule can not occupy same raceway or wireway as non service conductors.

 

[PaulEd]

Thanks guys.

It’s a legally required generator on the roof of a building. So I’m assuming 701 is the applicable section

I’m not referring to feeders but branch circuits from panels. Some branches are fed from the POCO and some from panels that are also fed from POCO but under power outages are fed from the generator.

It seems that 701.10(A) permits this unless I’m miss reading it ?

 

[kwired]

Thanks guys.

It’s a legally required generator on the roof of a building. So I’m assuming 701 is the applicable section

I’m not referring to feeders but branch circuits from panels. Some branches are fed from the POCO and some from panels that are also fed from POCO but under power outages are fed from the generator.

It seems that 701.10(A) permits this unless I’m miss reading it ?

Branch circuits that are to be on legally required standby system can't occupy same raceway as other circuits not on the legally required standby system. Such circuits can and usually are supplied by normal power via the normal side of the transfer switch when normal power is active. From there it it can vary some but eventually it usually comes down to a feeder supplying a panel that is where all the standby circuits originate and they go out to the loads that are required to be on legally required standby system - in wiring methods that don't mix with other non legally required loads.

 

[david]

Seen a lot of engineered drawings identifying the panel as N/E those branch circuits are installed in conduits that only supply normal/emergency loads such as required egress lighting.

 

[PaulEd]

Branch circuits that are to be on legally required standby system can't occupy same raceway as other circuits not on the legally required standby system. Such circuits can and usually are supplied by normal power via the normal side of the transfer switch when normal power is active. From there it it can vary some but eventually it usually comes down to a feeder supplying a panel that is where all the standby circuits originate and they go out to the loads that are required to be on legally required standby system - in wiring methods that don't mix with other non legally required loads.

But doesn’t 701.10(A) say you can?
“The legally required standby system wiring shall be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring”

 

[david]

But doesn’t 701.10(A) say you can?
“The legally required standby system wiring shall be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring”

Note: an N/E panel simplifies things like securing un authorized access to the required branch circuits.
Also note the 10 sec. Verses 60 sec transfer requirement.

When legally required systems back up egress lighting and exit signs those are going to be unit eguipment.

Having a N N/E panel does simplify the supply system
And most engineers do not mix normal non required branch circuits with legally required

But by code you are allowed to.

Identifying junction box and label requirements and transfer times are some of the reasons legally required 701 is used over 700 emergency systems

Also note building codes may only call them stand by systems. You can't mix emergency required but you can legally required.

But as noted your not going to to see that designed that way very often