Generators, Distros, and Disconnects

Alitaido

Member
I have been doing a little "light reading" in the NEC, but I can't seem to find a clear answer for this: if you are running a show outdoors, on a generator, can you run power straight to your distro and dimmers without a disconnect between them and the generator? The distro in question has breakers for each circuit, just not a main disconnect. Power comes from the generator into the distro and back out (cam in/cam out) to the dimmers.

Thanks for your thoughts!
 
The generators I work with typically have a main breaker next to the lugs used to connect to the generator. My presumption is that this qualifies as the main disconnect, and that your distro wouldn't necessarily need a main breaker on the panel, assuming that everything is appropriately matched for capacity. Obviously, if you're running 100 amp feeder to a 100 amp distro panel from a 400 amp generator output, then you'd want something early on in the chain to protect at the 100 amp level.

I'm sure others here will be able to provide chapters and verses to prove or disprove these presumptions.
 
I have been doing a little "light reading" in the NEC, but I can't seem to find a clear answer for this: if you are running a show outdoors, on a generator, can you run power straight to your distro and dimmers without a disconnect between them and the generator? The distro in question has breakers for each circuit, just not a main disconnect. Power comes from the generator into the distro and back out (cam in/cam out) to the dimmers.

Thanks for your thoughts!
I believe that unless the distro has a plug on the end designed to attach to a NEMA 14-50 or something like that - where it's assumed that the supply receptacle will have appropriate over current protection, you need to have your own OCPD to protect your feeder wires.
 
I have been doing a little "light reading" in the NEC, but I can't seem to find a clear answer for this: if you are running a show outdoors, on a generator, can you run power straight to your distro and dimmers without a disconnect between them and the generator? The distro in question has breakers for each circuit, just not a main disconnect. Power comes from the generator into the distro and back out (cam in/cam out) to the dimmers.

Thanks for your thoughts!

You have a lot going on in this question:

Where is a disconnect required?
Where is overcurrent protection required and at what rating?
What is the required ampacity of the feeder from the generator?

NEC article 445 provides some of the answers.

Section 445.18 requires a lockable disconnect for the generator unless
(1) The driving means of the generator can be readily shut down and
(2) The generator is not arranged to operate in parallel with another generator or another source.

Section 445.12 requires overcurrent protection to prevent overload of the generator. This might be integral to the generator.

Section 445.13 requires feeders of 115% of the nameplate rating of the generator, unless "the design and operation of the generator prevent overloading", in which case the feeder must be 100% of the nameplate rating.

The general articles of the code require overcurrent protection for all conductors. So, the answer to your question about an overcurrent protective device (with or without a disconnect) needs further analysis of:

1. The nameplate rating of the generator
2. The size of the feeder conductors
3. The aggregate possible load from your distro that has no main breaker
4. The connected load of the dimmer rack

ST
 

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