What type of cables should be used to wire a Generator?

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stcalle

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In the NEC 2008 article 338.10, it says that service entrance cables (type SE/USE) shall be permitted to be used as service entrance conductors and shall be installed in accordance with Article 230.6, 230.7.
Article 230.6 states that you use type SE/USE cable when you have conductors considered to be outside the building.

I see these articles as basically saying, when you are installing your service entrance conductors that connect the electric utility to your main disconnect in your facility, you need to use SE/USE cables.

However, when I looked in Article 100, the definition for service says that electric energy to a service can only be supplied by the serving utility. If electric energy is supplied by other than the serviing utility, the supplied conductors are considered feeders.

So this leads me to think that a generator is not considered a service thus you would not have to use SE/USE cables.


So this is the scenario:
1. You have the electric utility service connected to a fused service switch.
2. The service switch is connected to the normal side of an automatic transfer switch (ATS)
3. You have a permanent generator connected to a circuit breaker.
4. The circuit breaker is connected to the reserve side of the ATS.
5. You use SE/USE cables when connecting the utility service to the fused service switch.
6. You use regular cables such as THHN/THWN to connnect the fused service switch to the ATS.


What type of conductors should be used to connect the permanent generator to the circuit breaker?

Would answering this question depend on where the generator is installed?, meaning if the generator is permanently installed outside the facility then you need to use SE/USE cables to connect the generator to the ATS but if the generator is permanently installed inside the facility you can use other types of cables?

Sorry for the long confusing question.
 
you can use any chapter 3 wiring method that is allowed. you are never required to use USE or SE, in fact they are often problematic. I've always piped gensets, so I don't think I've ever used anything but thhn/thwn. If you like to direct bury and the ATS is on the outside, USE would be fine (except where subject to damage/exposed to sunlight)
 
I think you need to consider where your main bonding jumper is, since it is inside the fused service disconnect, you want a three pole transfer switch and a four wire run out to the generator with no bonding jumper at the genset.
 
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