Mixing branch circuits

[Dexie123]

Hello

I am working in a building that has multiple services. If I want to mix normal power branch circuit for lighting from two normal supplied services(utility power) in one conduit or lighting strut would this be permitted?

If not what prohibits this?

Would anything change if one of those services is fed from a power source other than utility power?

Thank you

 

[augie47]

The only problem I can think of would be if one of the supplies was considered "emergency power" in which case 700.10 would limit the areas where the two circuits can be mixed.

 

[don_resqcapt19]

Hello

I am working in a building that has multiple services. If I want to mix normal power branch circuit for lighting from two normal supplied services(utility power) in one conduit or lighting strut would this be permitted?

If not what prohibits this?

Would anything change if one of those services is fed from a power source other than utility power?

Thank you

How does the building have multiple services serving a single occupancy? In general each building or occupancy is only permitted to have one service.

 

[Dexie123]

It's a massive building project. There are I believe 5 services.

 

[electricalist]

What are the voltages of each "service" and are they 3 wire or 4 wire?

Sent from my SPH-L720T using Tapatalk

 

[Dexie123]

What are the voltages of each "service" and are they 3 wire or 4 wire?

Sent from my SPH-L720T using Tapatalk

For lighting. 277v with nuetral each. Assuming fed from a 480/277 w neutral service

 

[don_resqcapt19]

I don't know any code that says you can't do it, but I don't like mixing conductors from two different services in a common conduit.

 

[Dexie123]

I don't know any code that says you can't do it, but I don't like mixing conductors from two different services in a common conduit.

I don't either Don. This conversation is strictly to further my understanding of the code

 

[dema]

Insulation

Insulation

The wiring all has to have insulation rated for the highest voltage. So if you are using 120V and 480V in the same conduit - the 120V wiring has to be 480V rated. And I don't like the idea either. Too easy for someone to think all the conductors are turned off but some aren't.

 

[don_resqcapt19]

The wiring all has to have insulation rated for the highest voltage. So if you are using 120V and 480V in the same conduit - the 120V wiring has to be 480V rated. And I don't like the idea either. Too easy for someone to think all the conductors are turned off but some aren't.

It is rare to find conductors for power and lighting circuits installed in conduit that do not have 600 volt insulation.
Don't forget about the branch circuit identification requirements in 210.5(C) and the neutral grouping/identification rules in 200.4(B).