| Click to Post a New Message!
Page [ 1 ] |
|
|
|
Portable Generator House Backup Grounding
I have a Portable Generator that is connected to a transfer switch via a 240 twist connector. Is it true that since it is connected to the transfer switch which is grounded via the main panel that I don't have to ground the Portable Genset with a ground stake directly to the Portable Genset?
My generator a manual just says to obey local codes in regards to using the grounding terminal. My dealer says you would only ground the generator if it was not connected to a whole house grounded panel.
|
|
 Add Photo
Bookmarks: |
|
| |
|
Portable Generator House Backup Grounding
I searched for the electric code on grounding generators which I posted below. It seems that if my set up is not a "Separately derived system" I do not need to ground it at the generator. The code suggests that most transfer switches do no require a separate Gen-set ground because you would have to go out of your way to make it a separately derived system, not normal practice.
Anyway I am in an area I don't have any knowledge on and appreciate everyone's input.
I will have to check with the Electrical inspector to make sure that is the standard that they approved when it was installed 3 years ago. I'd much rather sink the grounding rod then be wrong, can grounding a system that does not not require grounding at the Genset be a problem or is it just redundant?
"Portable generators are often used for backup power at traffic signals, buildings, structures and special events. Ground rods (grounding electrodes) are only required if the generator is a separately derived system. (For the complete text of sections cited please see the 2002 NEC)
What is a Separately Derived System?
The NEC in Article 100 defines a Separately Derived System as:
Separately Derived System. A premises wiring system whose power is derived from a battery, from a solar photovoltaic system, or from a generator, transformer, or converter windings, and that has no direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.
The key to knowing if a generator is a Separately Derived System is not the generator, but rather the transfer switch. If the transfer switch does not transfer the neutral (grounded conductor), then the generator has a “solidly connected” grounded circuit conductor and the generator is not a separately derived system.
If the generator is connected to a transfer switch that transfers the neutral, and the generator does not have a “solidly connected” grounded circuit conductor, then it is a separately derived system. A separately derived system requires a connection to a grounding electrodes or ground rod(s).
A transfer switch is required between the generator and connected load. It provides isolation and prevents backfeed to the utility source from the generator. New for the 2002 NEC is Section 702.6 Transfer Equipment, which requires suitable equipment for the use, designed and installed so as to prevent the inadvertent interconnection of normal and alternate sources of supply in any operation of the transfer equipment. Interlocked circuit breakers or manual double pole, double throw, center off switch can be used.
Most generators are connected through transfer switches that do not transfer the neutral. Switching the neutral is done by design, due to other electrical requirements.
Where required for a generator, the purpose of the ground rod(s) at a generator is to limit the voltage from surges, lightning or unintentional contact with high voltage lines, and to limit the voltage to ground on conductive metal parts."
|
|
Add Photo
Bookmarks: |
|
| |
|
Portable Generator House Backup Grounding
|
Quote:
|
If you do not have a grounded (neutral) conductor from the generator to the house you will have an open neutral and will damage the household electrical equipment. ....
|
|
Hi Greg thanks for your help! I am asking my towns electrical inspector for help on this.
In reference to your statement above, if I buy a cheap outlet tester that tests for seven conditions: ground fault interruption, open ground, open neutral, open hot, hot/ground reverse, hot/neutral reverse, and correct wiring, and test outlets while under generator power will that help determine if there is an issue with my set up ?
By the way I have been using a portable generator with current switch for a couple of years during several multi week outages, running the well, two furnaces, hot water heater, wide screen led TV, computers etc. with no problems.
I just sold my old gen and bought an new Honda EM6500 and reading the manual prompted my question and research on this.
|
|
Add Photo
Bookmarks: |
|
| |
|
Portable Generator House Backup Grounding
I bought an outlet tester and tested the circuits in the house under generator power and they show the outlets being correctly wired. Same on the Generator 120 outlets.
The tester tests for open ground,open neutral, open hot,hot grd reverse,hot neutral reverse.
On the the transfer switch, I guess I don't have a transfer type switch really. Transfer switches take splices off the main panel and fill your main power box with twist connectors, not a pretty site in my opinion.
What I have is a Generator Sub Panel. My house wiring that will be run by the generator has home run wires that connects directly to the Generator subpanel. The generator subpanel is fed from one of my main panels by a 60 amp breaker.
The generator sub panel has two breakers on an interlock that toggles between Genset 30amp and House Panel 60 amp, only allowing one or the other breaker to be on.
So my set up has no user manual that an after market "transfer switch" would have.
|
|
Add Photo
Bookmarks: |
|
| |
|
Page [ 1 ] | Thread 185611 Filter by Poster:
4 | 3 | 1 | 5 | 1 |
|
()
Picture of the Day
crunch
Unanswered Questions
Active Subjects
Hot Topics
Featured Suppliers
|
Gas Generator Weather Protecti
12-05-2012, 08:01 
Digg It 
Del.icio.us