Another Generator Grounding Question

[3timesgone]

I am using an interlock switch to disconnect the MAIN when generator is in use. The neutral is not switched....only the hot feeds. I have a Briggs EXL8000 which has a bonded neutral. I am setting it up not far from my utility inlet.

Question: To solve any grounding issues, couldn't I simply connect a ground wire of suitable gauge from my generator ground nut directly to my existing service grounding rod? If this is the case, I should not have to reconfigure my generator to a floating ground.....I would think. (???) Am I missing something? I really do not want to manipulate the generator if possible.

 

[templdl]

I am using an interlock switch to disconnect the MAIN when generator is in use. The neutral is not switched....only the hot feeds. I have a Briggs EXL8000 which has a bonded neutral. I am setting it up not far from my utility inlet.

Question: To solve any grounding issues, couldn't I simply connect a ground wire of suitable gauge from my generator ground nut directly to my existing service grounding rod? If this is the case, I should not have to reconfigure my generator to a floating ground.....I would think. (???) Am I missing something? I really do not want to manipulate the generator if possible.

Are you saying that the generator's neutral and ground are already bonded together?

 

[ActionDave]

I am using an interlock switch to disconnect the MAIN when generator is in use. The neutral is not switched....only the hot feeds. I have a Briggs EXL8000 which has a bonded neutral. I am setting it up not far from my utility inlet.

Question: To solve any grounding issues, couldn't I simply connect a ground wire of suitable gauge from my generator ground nut directly to my existing service grounding rod? If this is the case, I should not have to reconfigure my generator to a floating ground.....I would think. (???) Am I missing something? I really do not want to manipulate the generator if possible.

Not sure what you mean by "floating ground" - are you talking about the grounded/neutral or an equipment grounding conductor?

In a non SDS (the neutral/grounded conductor is not switched) there is only one bond and it is at the main, whether that is the service disconnect or a service rated transfer switch, everything else is treated like a sub-panel.

 

[ceb58]

I am using an interlock switch to disconnect the MAIN when generator is in use. The neutral is not switched....only the hot feeds. I have a Briggs EXL8000 which has a bonded neutral. I am setting it up not far from my utility inlet.

Question: To solve any grounding issues, couldn't I simply connect a ground wire of suitable gauge from my generator ground nut directly to my existing service grounding rod? If this is the case, I should not have to reconfigure my generator to a floating ground.....I would think. (???) Am I missing something? I really do not want to manipulate the generator if possible.

This is why UL has the statement of switching the neutral with a portable unit.

 

[goldstar]

I am using an interlock switch to disconnect the MAIN when generator is in use. The neutral is not switched....only the hot feeds. I have a Briggs EXL8000 which has a bonded neutral. I am setting it up not far from my utility inlet.

Question: To solve any grounding issues, couldn't I simply connect a ground wire of suitable gauge from my generator ground nut directly to my existing service grounding rod? If this is the case, I should not have to reconfigure my generator to a floating ground.....I would think. (???) Am I missing something? I really do not want to manipulate the generator if possible.

I believe you mean an "interlock kit" and not an "interlock switch". If you're doing this correctly you should be using a 20, 30 or 50 amp power inlet port on the outside of the house which, in turn, is connected to the main breaker panel neutral bar and a corresponding generator breaker in the main breaker panel. If the main breaker is on you will not be able to back-feed from the generator. Is this what you're doing ?

If so, the generator will be grounded to the main breaker panel by the 4-wire, twist-lock power cord you should be using. Before you install the power cord you can check to see if the neutral and ground are bonded together in the generator simply by using a VOM.

 

[goldstar]

This is why UL has the statement of switching the neutral with a portable unit.

Can you please cite that section ? Thanks.

 

[zbang]

How about this?
http://books.google.com/books?id=Jf...=ul generator separate neutral ground&f=false

which ref's UL 2201 "Portable Electric Generators"

 

[jwelectric]

Can you please cite that section ? Thanks.

110.3(B) and UL FTCN is the information you are asking for

 

[goldstar]

110.3(B) and UL FTCN is the information you are asking for

Shown below are the sections that jwelectric cited so that we can all speak intelligently. While I think JW makes a valid point (he has brought this up many times before and we've discussed and argued this more times than I care to remember) this is not the way these portable units are being marketed throughout the country, at least as far as I can tell. If this catches on and if EI's start to enforce these rulings it will become an issue. If homeowners are not permitted to make safe connections of portable generators to their homes using the 20, 30 or 50 amp - 120/240V receptacles, the units will start to be manufactured with 120 V outputs ONLY and generator sales will plummet. Then maybe we'll see the manufacturers speak up.

HO's will be forced to have one or several of these units installed ( http://www.ezgeneratorswitch.com/ ) which does fit the bill by transferring the neutral. But you still have to worry about the grounding of the generator. You can safely run your heating system (if it's 120 V) because it allows you to (extension) cord and plug attached to the generator 120 V receptacles. A much more costly and potentially dangerous installation IMHO. It's hard enough trying to explain to a HO how to reset a circuit breaker. Can you imagine the chaos this will cause ?

From the NEC :

110.3 Examination, Identification, Installation, and Use
of Equipment.

(B) Installation and Use. Listed or labeled equipment
shall be installed and used in accordance with any instructions
included in the listing or labeling.

From the UL White Book

ENGINE GENERATORS FOR PORTABLE
USE (FTCN)
GENERAL
This category covers internal-combustion-engine-driven generators rated
15 kW or less, 250 V or less, which are provided only with receptacle outlets
for the ac output circuits. The generators may incorporate alternating or
direct-current generator sections for supplying energy to battery charging
circuits.
When a portable generator is used to supply a building wiring system:
1. The generator is considered a separately derived system in accordance
with ANSI/NFPA 70, ??National Electrical Code?? (NEC).
2. The generator is intended to be connected through permanently
installed Listed transfer equipment that switches all conductors other
than the equipment grounding conductor.
3. The frame of a Listed generator is connected to the equipment grounding
conductor and the grounded (neutral) conductor of the
generator. When properly connected to a premises or structure, the
portable generator will be connected to the premises or structure
grounding electrode for its ground reference.
4. Portable generators used other than to power building structures are
intended to be connected to ground in accordance with the NEC.
RELATED PRODUCTS
Engine generators intended for use in recreational vehicles are covered
under Engine Generators for Recreational Vehicles (FTCZ).
Engine Generators for Portable Use (FTCN)?Continued
Engine generators intended for stationary use are covered under Engine
Generators (FTSR).
Wind-driven generators are covered under Wind Turbine Generating System
Subassemblies (ZGZJ).
Motor-generator sets and flywheel energy storage systems are covered
under Motor-Generator Sets (PQYW).
Generators, also referred to as generator heads or alternators, intended for
use in an engine generator are covered under Generators (JZGZ).
ADDITIONAL INFORMATION
For additional information, see Engine Generators (FTCA), Building Materials
(AABM) and Electrical Equipment for Use in Ordinary Locations
(AALZ).
REQUIREMENTS
The basic standard used to investigate products in this category is UL
2201, ??Portable Engine-Generator Assemblies.??
UL MARK
The Listing Mark of Underwriters Laboratories Inc. on the product is the
only method provided by UL to identify products manufactured under its
Listing and Follow-Up Service. The Listing Mark for these products
includes the UL symbol (as illustrated in the Introduction of this Directory)
together with the word ?LISTED,? a control number, and the product name
UL, in performing its functions in accordance with its objectives, does not
assume or undertake to discharge any responsibility of the manufacturer or
any other party. UL shall not incur any obligation or liability for any loss,
expense or damages, including incidental or consequential damages, arising
out of or in connection with the use, interpretation of, or reliance upon this
Guide Information.

 

[ceb58]

Shown below are the sections that jwelectric cited so that we can all speak intelligently. While I think JW makes a valid point (he has brought this up many times before and we've discussed and argued this more times than I care to remember) this is not the way these portable units are being marketed throughout the country, at least as far as I can tell. If this catches on and if EI's start to enforce these rulings it will become an issue. If homeowners are not permitted to make safe connections of portable generators to their homes using the 20, 30 or 50 amp - 120/240V receptacles, the units will start to be manufactured with 120 V outputs ONLY and generator sales will plummet. Then maybe we'll see the manufacturers speak up.

HO's will be forced to have one or several of these units installed ( http://www.ezgeneratorswitch.com/ ) which does fit the bill by transferring the neutral. But you still have to worry about the grounding of the generator. You can safely run your heating system (if it's 120 V) because it allows you to (extension) cord and plug attached to the generator 120 V receptacles. A much more costly and potentially dangerous installation IMHO. It's hard enough trying to explain to a HO how to reset a circuit breaker. Can you imagine the chaos this will cause ?

I think the real question is, what are we as contractors going to do? If some one calls and wants a generator connection, and we get there and find that they want a connection for a portable unit. How do you defend your price for the correct installation against the price for a simple interlock and cord connection? In cases of outages due to storms and such HO's are going to do what they have always done, hook it up the best way they can taking advice from their brother-in-law who changed 3 light blubs in one day. If there is an inspection do the EI's know what they are looking at? They certainly are not going to go around in a emergency situation looking for non-compliant installations. Until some one dose the dryer plug hook up and kills another lineman
For me personally I give the price and a copy of the UL statement. If they go for it they go for it. If not then I sleep well at night.

 

[templdl]

A lot of speculation and where is the OP?
I asked whether or not the neutral and grounding conductor were bonded together at the generator. This would determine whether or not there would have to be a switching neutral or not as I understand it.
But since the OP hasn't replied it's nothing but speculation.

 

[jwelectric]

I think the real question is, what are we as contractors going to do?

Ceb58

In the course of teaching all three levels of electrical inspectors at Randolph Community College for the past decade I have had several fine electricians that were required to take the 40 hour Level I class by the licensing board because they did something they wasn?t supposed to be doing. One of these gentlemen was there due to something that he had done way back in late 1979.

I would be very careful of what I did under my license.

 

[goldstar]

I think the real question is, what are we as contractors going to do? If some one calls and wants a generator connection, and we get there and find that they want a connection for a portable unit. How do you defend your price for the correct installation against the price for a simple interlock and cord connection?

As long as manufacturers keep making portables with 120/240V outputs and as long as they keep making interlock kits, if not me or you then someone else will be installing these and making $$$. When they stop making these units and devices and when EI's start knocking down jobs then that's when it stops.

In cases of outages due to storms and such HO's are going to do what they have always done, hook it up the best way they can taking advice from their brother-in-law who changed 3 light bulbs in one day. If there is an inspection do the EI's know what they are looking at? They certainly are not going to go around in a emergency situation looking for non-compliant installations. Until some one dose the dryer plug hook up and kills another lineman
For me personally I give the price and a copy of the UL statement. If they go for it they go for it. If not then I sleep well at night.

If 10 linemen are killed because HO's used their brothers-in-law to make dangerous back-fed connections through their dryers would your conscience feel better because you quoted them the right price and material to do the job and then didn't get the job or would you feel better knowing that you used an interlock kit, made the right connections and didn't kill any linemen ?

This is not an argument about what's written in UL-FTCN or NEC 110.3(B). We can all read those sections. It's about what is being mass-marketed to the public and what rules are or are not being enforced.

If we can move away from UL-FTCN for a moment, what is the danger in using a portable generator, connecting it to house wiring and bonding the neutrals together as opposed to transferring the neutral in a separate panel ? Do manufacturers know something we don't ?

 

[qcroanoke]

what is the danger in using a portable generator, connecting it to house wiring and bonding the neutrals together as opposed to transferring the neutral in a separate panel ?

I would like a clear answer on that too.
The generator I have is not bonded so it is a moot point for me. but as stated, what is the danger?
And what are the odds of it happening?

 

[ActionDave]

I would like a clear answer on that too.
The generator I have is not bonded so it is a moot point for me. but as stated, what is the danger?
And what are the odds of it happening?

There is no extra danger that does not exist when the home is being supplied by utility power. It is
not really a big deal if the generator is internally bonded in as much as most portable gennies are connected with a rubber cord.

 

[templdl]

There is no extra danger that does not exist when the home is being supplied by utility power. It is
not really a big deal if the generator is internally bonded in as much as most portable gennies are connected with a rubber cord.

When are you allowed by the NEC to bond the neutral to the ground at a point other than at the service entrance? Should the genset's neutral and grounding conductor be bonded together and there is no switched neutral that is an issue if the genset is being used as an emergency source of power as /the neutral and grounding conductor will be connected at both the service entrance and genset.

 

[Nycedreemz]

Just use a four wire cord (L14-20, L14-30 etc.) from your gen to your inlet of the same style and wire the inlet accordingly to your panel and with your interlock kit, you're good to go!

 

[ceb58]

When are you allowed by the NEC to bond the neutral to the ground at a point other than at the service entrance? Should the genset's neutral and grounding conductor be bonded together and there is no switched neutral that is an issue if the genset is being used as an emergency source of power as /the neutral and grounding conductor will be connected at both the service entrance and genset.

Just use a four wire cord (L14-20, L14-30 etc.) from your gen to your inlet of the same style and wire the inlet accordingly to your panel and with your interlock kit, you're good to go!

Read the above and explain how " your good to go" if there is a N - G bond in the generator. If some one came asking about bonding the N-G in a sub panel every one would jump in stating the danger and code violations in doing that. Just because its a generator doesn't change anything. It is the same principle.

As long as manufacturers keep making portables with 120/240V outputs and as long as they keep making interlock kits, if not me or you then someone else will be installing these and making $$$. When they stop making these units and devices and when EI's start knocking down jobs then that's when it stops. If 10 linemen are killed because HO's used their brothers-in-law to make dangerous back-fed connections through their dryers would your conscience feel better because you quoted them the right price and material to do the job and then didn't get the job or would you feel better knowing that you used an interlock kit, made the right connections and didn't kill any linemen ?

This is not an argument about what's written in UL-FTCN or NEC 110.3(B). We can all read those sections. It's about what is being mass-marketed to the public and what rules are or are not being enforced.

If we can move away from UL-FTCN for a moment, what is the danger in using a portable generator, connecting it to house wiring and bonding the neutrals together as opposed to transferring the neutral in a separate panel ? Do manufacturers know something we don't ?

I understand what you are saying but it is all rhetorical. IF is probably the largest word in our language. What IF this, what IF that. IF I turned down the job because I could not follow the code then I could live with my conscience. I am looking at the situation this way. On one hand you have a home owner who may have very little or no electrical experience. If I connect it the way that it is described above and IF there is some failure in the wiring and it energizes the non-cc parts and/or the frame of the generator and the HO goes to service the generator and is killed then I would be clearly at fault. On the other hand IF a HO makes up a suicide cord and plugs it in and back feeds on the utility the POCO workers are supposed to be trained and equipped to handle these types of situations. I am not saying it has never happened or that it will never happen again but with the abundance of HO's with generators now verse the past I am sure the POCO's have addressed the situation and how to deal with it.

 

[templdl]

The OPer never responded. As such aren't you guys chasing you tail with assumptions and speculation?
The is what the OP posted:
"Another Generator Grounding Question
I am using an interlock switch to disconnect the MAIN when generator is in use. The neutral is not switched....only the hot feeds. I have a Briggs EXL8000 which has a bonded neutral. I am setting it up not far from my utility inlet.
Question: To solve any grounding issues, couldn't I simply connect a ground wire of suitable gauge from my generator ground nut directly to my existing service grounding rod? If this is the case, I should not have to reconfigure my generator to a floating ground.....I would think. (???) Am I missing something? I really do not want to manipulate the generator if possible."

 

[ActionDave]

When are you allowed by the NEC to bond the neutral to the ground at a point other than at the service entrance? Should the genset's neutral and grounding conductor be bonded together and there is no switched neutral that is an issue if the genset is being used as an emergency source of power as /the neutral and grounding conductor will be connected at both the service entrance and genset.

Not saying it is allowed. Just saying it is not the worst thing.

Read the above and explain how " your good to go" if there is a N - G bond in the generator. If some one came asking about bonding the N-G in a sub panel every one would jump in stating the danger and code violations in doing that. Just because its a generator doesn't change anything. It is the same principle.

That is because when it is a sub-panel there is some metal parts involved that will end up with some neutral current on them. For a portable generator the connection is a rubber cord 99.9% of the time.