Temporary Emergency Generator Installations
- Thread starter superdave02
- Start date
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
It sounds like the NEC would call these optional standby systems not 'emergency' or backup units. Again a common language with multiple meanings per word gets us into trouble.
- Location
- Bremerton, Washington
Agree. FEMA terminology is not code terminology. But being out installing generators those without power understand emergency generator
The only way I could see the NEC not applying if your in a actual 'state of emergency' declared by the governor, this would be a very short duration rig job meant for just a few weeks tops. If your going around installing generators for disaster preparation the the NEC rules apply.
As an electrician, I understand your concern regarding the installation of Temporary Emergency Generators during hurricane/typhoon seasons. While these installations may not be covered by the NEC, they are addressed by OSHA guidelines. Regarding FEMA generators, the need for a ground rod depends on specific circumstances and whether they are considered a separately derived system. To ensure accurate guidance, I recommend consulting with a qualified electrician who can assess your installation and provide personalized advice based on OSHA requirements and industry best practices.
I'm going to say yes. OSHA publishes a document titled" Grounding Requirements for Portable Generators" Relevant portion posted below. I had an interesting interaction with an inspector once where I was not required to place a ground rod due to all cord and plug connected load. I pointed out the rules and her reply was that the instructions on the side of the generator say to connect a ground rod so its required. Easier to drive a rod than take that any further.
Under the following conditions, OSHA
directs (29 CFR 1926.404(f)(3)(i)) that the
frame of a portable generator need not be
grounded (connected to earth) and that the
frame may serve as the ground (in place of
the earth):
• The generator supplies only equipment
mounted on the generator and/or cord-
and plug-connected equipment through
receptacles mounted on the generator,
§ 1926.404(f)(3)(i)(A), and
• The noncurrent-carrying metal parts of
equipment (such as the fuel tank, the inter-
nal combustion engine, and the generator’s
housing) are bonded to the generator
frame, and the equipment grounding con-
ductor terminals (of the power receptacles
that are a part of [mounted on] the genera-
tor) are bonded to the generator frame,
§ 1926.404(f)(3)(i)(B).
Thus, rather than connect to a grounding
electrode system, such as a driven ground
rod, the generator’s frame replaces the
grounding electrode.
If these conditions do not exist, then a
grounding electrode, such as a ground rod,
is required.
If the portable generator is providing electric
power to a structure by connection via a
transfer switch to a structure (home, office,
shop, trailer, or similar) it must be connected
to a grounding electrode system, such as a
driven ground rod.
Under the following conditions, OSHA
directs (29 CFR 1926.404(f)(3)(i)) that the
frame of a portable generator need not be
grounded (connected to earth) and that the
frame may serve as the ground (in place of
the earth):
• The generator supplies only equipment
mounted on the generator and/or cord-
and plug-connected equipment through
receptacles mounted on the generator,
§ 1926.404(f)(3)(i)(A), and
• The noncurrent-carrying metal parts of
equipment (such as the fuel tank, the inter-
nal combustion engine, and the generator’s
housing) are bonded to the generator
frame, and the equipment grounding con-
ductor terminals (of the power receptacles
that are a part of [mounted on] the genera-
tor) are bonded to the generator frame,
§ 1926.404(f)(3)(i)(B).
Thus, rather than connect to a grounding
electrode system, such as a driven ground
rod, the generator’s frame replaces the
grounding electrode.
If these conditions do not exist, then a
grounding electrode, such as a ground rod,
is required.
If the portable generator is providing electric
power to a structure by connection via a
transfer switch to a structure (home, office,
shop, trailer, or similar) it must be connected
to a grounding electrode system, such as a
driven ground rod.
- Occupation
- Licensed Electrician
Per the OP he does not have an SDS so his generator is connected to the building grounding electrode system.
OP states that there is no ECG. If the neutral is bonded to ground at the generator as OP states, then the neutral needs to be switched.
Sberry
Senior Member
- Location
- Brethren, MI
- Occupation
- farmer electrician
If the portable generator is providing electric
power to a structure by connection via a
transfer switch to a structure (home, office,
shop, trailer, or similar) it must be connected
to a grounding electrode system, such as a
driven ground rod.
The travel trailer crowd goes thru this, you will see someone out pounding a 3 ft stake in the ground. Whats it for,,, so I dont get shocked,, I say what is it you are trying to do,,, I am pounding a rod,,, ha But if premise connected is simply to reduce potential difference between the power and the ground one is standing on, mostly from leakage, (with premise not always from same service, may be the same system tranny etc) same thing is may do in regular situation. I can see a difference in tire mounted or steel skid mounted, its already on the same ground.
Sall genset or welder in a pickup, there is no other ground connection, rod wouldnt do a thing.
power to a structure by connection via a
transfer switch to a structure (home, office,
shop, trailer, or similar) it must be connected
to a grounding electrode system, such as a
driven ground rod.
The travel trailer crowd goes thru this, you will see someone out pounding a 3 ft stake in the ground. Whats it for,,, so I dont get shocked,, I say what is it you are trying to do,,, I am pounding a rod,,, ha But if premise connected is simply to reduce potential difference between the power and the ground one is standing on, mostly from leakage, (with premise not always from same service, may be the same system tranny etc) same thing is may do in regular situation. I can see a difference in tire mounted or steel skid mounted, its already on the same ground.
Sall genset or welder in a pickup, there is no other ground connection, rod wouldnt do a thing.
Last edited:
Sberry
Senior Member
- Location
- Brethren, MI
- Occupation
- farmer electrician
Take the RV scenario, with a genset no potential difference between the trailer and the ground, connect it to premise power and there may be a possibility?
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
where does it say in the code that temporary generator installations are exempt from the code?
- Occupation
- Licensed Electrician
The is nothing more than a chair booster till someone adopts it and enforces it.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
The NEC only applies to 'installations'. To the extent 'temporary' means 'not installed', the NEC may not apply. For example in my opinion the NEC does not apply to cord and plug connected portable generators.
That said, it seems like the OP is doing work which, however temporary it may be, rises to the level of installation, in the sense that it goes beyond just moving things around and plugging them in.
Fred B
Senior Member
- Location
- Upstate, NY
- Occupation
- Electrician
Maybe not the genset itself (governed by multiple UL standards), but how it connects into the permanent structure wiring NEC does apply. It also applies to the NG bonding at the Genset related to interconnection with existing buildings electrical system. In most instances, NG bonding not acceptable for "portable" generators connected into a building system (SDS exception separate rules).
Only go around is that it never gets connected into the existing building, multiple extension cords to individual corded appliances.
Generally grounding accomplished via an EGC not a GEC.
Fred B
Senior Member
- Location
- Upstate, NY
- Occupation
- Electrician
Look at 700.3(F) Temporary Source of Power for Maintenance or Repair of the Alternate Source of Power.
While, generally these generator setups do not fall into the category of "Emergency Generators", more likely "Optional standby generators", but using your wording 700.3(F) would apply.
Then I see the only compliant means would be individual appliances connected via a cord, not tying into the building electrical system, OR treat as an SDS and all its requirements.
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
Not sure if this was already asked, but is thneutral bonded to the generator frame?
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
Ok so I read back and apparently the gensets are NG bonded, so EGC is a parallel path for neutral currents. I guess you don't want to drive a ground rod because these things are sitting on pavement or concrete?
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Right but that arguably can't include requiring a grounding electrode for a temporarily positioned portable cord and plug connected generator. Nor does the NEC attempt to require this anywhere, to my knowledge.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
He said they don't install an EGC because the neutral is bonded at generator. Post #20.
No wire, no parallel path.
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
I don't know these specific gensets, but some of the larger ones I've worked with lifting the N-G bond was no big deal
I guess these things are just unsafe. For the nominal fee of $1 I would be happy to send a truck or trucks down to pick them up so they can be properly disposed of