Temporary Emergency Generator Installations

[superdave02]

Every hurricane/typhoon season I post a question about our installations. Here is where I am at this year. Our Temporary Emergency Generator installations are not covered by the NEC. They are addressed by OSHA though. Anyway, these FEMA generators, do they need a ground rod or not, that is the question. They are not a separately derived system. Thoughts?

 

[tom baker]

The NEC has 3 articles on generators, 700, 701, and 702. Please review those articles as what you call an emergency generator may be an optionally required standby generator. An emergency generator has very strict rules.
Generator grounding is in Art 250.
What determines your generators being covered by OSHA? OSHA does adopt the latest NEC.
Why are your generators not separately derived?

 

[superdave02]

The NEC does not cover Temporary Emergency Generators. We use various connection points on a building or structure. The neutral is not switched and a transfer switch is not used.
Thoughts about if a grounding electrode is needed?

 

[letgomywago]

How do the various AHJs address this in writing there? If it's just an unspoken rule then it's not real. Hopefully the mains are disconnected before this is done.

 

[retirede]

You’re connecting to an existing electrical system that has a grounding electrode system. Adding a ground rod does absolutely nothing.

 

[superdave02]

No AHJ, no inspections, just FEMA subs installing temp gens. I say no ground rod needed.

 

[superdave02]

You’re connecting to an existing electrical system that has a grounding electrode system. Adding a ground rod does absolutely nothing.

My thoughts also.

 

[superdave02]

The generators are attached to large steel skids. 20kw to 455kw.

 

[ActionDave]

Every hurricane/typhoon season I post a question about our installations. Here is where I am at this year. Our Temporary Emergency Generator installations are not covered by the NEC. They are addressed by OSHA though. Anyway, these FEMA generators, do they need a ground rod or not, that is the question. They are not a separately derived system. Thoughts?

Then you don't need a ground rod.

 

[Joethemechanic]

One generator feeding one service, or one generator feeding multiple services?

 

[superdave02]

One generator feeding one service, or one generator feeding multiple services?

One generator per service.

 

[tom baker]

There is a provision in the NEC for connection of a generator without a transfer switch. It’s maybe in 590?

 

[Joethemechanic]

egc in the generator cable and no n-g bond at the generator?

 

[superdave02]

egc in the generator cable and no n-g bond at the generator?

We use single conductors and all gens are bonded. Anyway, I think it is unnecessary to install a grounding electrode conductor and wanted to here it from others.

 

[Joethemechanic]

We use single conductors and all gens are bonded. Anyway, I think it is unnecessary to install a grounding electrode conductor and wanted to here it from others

I'm not seeing any good reason for it.

 

[qcroanoke]

There is a provision in the NEC for connection of a generator without a transfer switch. It’s maybe in 590?

702.5 exception

 

[dkidd]

The NEC has 3 articles on generators, 700, 701, and 702. Please review those articles as what you call an emergency generator may be an optionally required standby generator. An emergency generator has very strict rules.
Generator grounding is in Art 250.
What determines your generators being covered by OSHA? OSHA does adopt the latest NEC.
Why are your generators not separately derived?

Separately derived would require switching the neutral.

 

[tortuga]

If I am not mistaken when you are awarded a contract by FEMA they send you a FEMA Contractor Handbook, in that they require installations to comply with the 'most recent edition' of the NEC. They have their own inspectors that inspect your work, that are also trained to work with the local AHJ. So there is no getting around the NEC with FEMA.

 

[dkidd]

Every hurricane/typhoon season I post a question about our installations. Here is where I am at this year. Our Temporary Emergency Generator installations are not covered by the NEC. They are addressed by OSHA though. Anyway, these FEMA generators, do they need a ground rod or not, that is the question. They are not a separately derived system. Thoughts?

There needs to be an equipment grounding conductor from the generator to the building grounding electrode system.

 

[superdave02]

There needs to be an equipment grounding conductor from the generator to the building grounding electrode system.

Our generators are bonded and so are the buildings main disconnects, so if we have a neutral we don't install a EGC for obvious reasons. These installations are not code compliant.