Portable Genny used as SDS

[K8MHZ]

Moot points?

Moot points?

Take a look at 400.7(A) which does not allow for the entrance panel of a dwelling to be supplied by a flexible cord, thus, the point of whether or not such a connection is considered cord and plug or not is moot, it is still a violation, IMO.

 

[Smart $]

Take a look at 400.7(A) which does not allow for the entrance panel of a dwelling to be supplied by a flexible cord, thus, the point of whether or not such a connection is considered cord and plug or not is moot, it is still a violation, IMO.

That's a very good point.

However, subject to interpretation, an argument could be made that an installation qualifies under 400.7(A)(6) and/or (7)...

400.7 Uses Permitted.
(A) Uses. Flexible cords and cables shall be used only for the following:
(1) Pendants
(2) Wiring of luminaires
(3) Connection of portable luminaires, portable and mobile signs, or appliances
(4) Elevator cables
(5) Wiring of cranes and hoists
(6) Connection of utilization equipment to facilitate frequent interchange
(7) Prevention of the transmission of noise or vibration
(8) Appliances where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection
(9) Connection of moving parts
(10) Where specifically permitted elsewhere in this Code

 

[K8MHZ]

That's a very good point.

However, subject to interpretation, an argument could be made that an installation qualifies under 400.7(A)(6) and/or (7)...

​

Not 6, this is being used as a permanent installation. Also, the 'utilization equipment' if you could stretch the definition to mean a panel, isn't being frequently interchanged.

Not 7, as the cord does nothing to change the amount of noise or vibration coming from the generator.

Ladies and Gentlemen of the Jury,

Have we come to a consensus yet?

To be honest, I stumbled across 400.7 while looking up something totally different, but I think it's sufficient enough to fail the installation. Now, it's more than just a ground rod or two, it's the entire connection.

 

[Smart $]

Not 6, this is being used as a permanent installation. Also, the 'utilization equipment' if you could stretch the definition to mean a panel, isn't being frequently interchanged.

Granted a stretch, but not an extreme stretch. The portable generator is portable, no matter the longevity of any single use. No. 6 is not written to say the utilization equipment is that which is frequently interchanged. It is only written so the connection provides for frequent interchange. Running a gennie full time will require its replacement more frequently than a POCO service.

Not 7, as the cord does nothing to change the amount of noise or vibration coming from the generator.

I completely disagree... and there is no stretching here. I believe if one used a rigid conduit wiring method, there would be an excessive amount of noise and vibration transferred to the dwelling structure.

 

[ceb58]

Not 6, this is being used as a permanent installation. Also, the 'utilization equipment' if you could stretch the definition to mean a panel, isn't being frequently interchanged.

Not 7, as the cord does nothing to change the amount of noise or vibration coming from the generator.

Ladies and Gentlemen of the Jury,

Have we come to a consensus yet?

To be honest, I stumbled across 400.7 while looking up something totally different, but I think it's sufficient enough to fail the installation. Now, it's more than just a ground rod or two, it's the entire connection.

My vote is it is not cord and plug equipment. Drive the rod, bond the N-G.

[

quote=Smart $;1246569]Granted a stretch, but not an extreme stretch. The portable generator is portable, no matter the longevity of any single use. No. 6 is not written to say the utilization equipment is that which is frequently interchanged. It is only written so the connection provides for frequent interchange. Running a gennie full time will require its replacement more frequently than a POCO service.

You not going down with out a fight are you

I completely disagree... and there is no stretching here. I believe if one used a rigid conduit wiring method, there would be an excessive amount of noise and vibration transferred to the dwelling structure.

[/QUOTE]

That's one I would like to see. Ridged connected to a portable gen.

 

[Smart $]

..You not going down with out a fight are you

...

I'm not going down... :roll:

 

[Smart $]

...That's one I would like to see. Ridged connected to a portable gen.

Grounding aside, how would you connect it without using cord and plug?

 

[ceb58]

Grounding aside, how would you connect it without using cord and plug?

We have ways

Now withstanding the jokes. The main question was the grounding. I hold to the oppion that the panel is not cord and plug equipment that falls under 250.34 (A) (1). The gen. is the only source of power for the building. As in most gen. it should have the first OCP so the ground and neutral should be bonded at the gen. with a driven rod. The panel on the building should be treated as a sub panel with the N-G separated.

Would I connect it with a cord and plug? Yes. I would do it for some of the reasons you posted. Moving the gen., replacing the gen. and so on. Would I drive a rod and connect it? Yes. The reason being I feel it is requried and I like watching my son drive rods

 

[K8MHZ]

We have ways

Now withstanding the jokes. The main question was the grounding. I hold to the oppion that the panel is not cord and plug equipment that falls under 250.34 (A) (1). The gen. is the only source of power for the building. As in most gen. it should have the first OCP so the ground and neutral should be bonded at the gen. with a driven rod. The panel on the building should be treated as a sub panel with the N-G separated.

Would I connect it with a cord and plug? Yes. I would do it for some of the reasons you posted. Moving the gen., replacing the gen. and so on. Would I drive a rod and connect it? Yes. The reason being I feel it is requried and I like watching my son drive rods

So far, I like this response the best.

The rod or rods at the generator may not actually do a whole lot, but as I read the NEC an electrode is required for the generator. I don't think it's permitted to power an entrance panel with a cord and plug and am going to suggest looking into a receptacle designed to feed a panel from a generator.

 

[SG-1]

So far, I like this response the best.

The rod or rods at the generator may not actually do a whole lot, but as I read the NEC an electrode is required for the generator. I don't think it's permitted to power an entrance panel with a cord and plug and am going to suggest looking into a receptacle designed to feed a panel from a generator.

Something like this:
http://www.interlockkit.com/?gclid=CNyI8OOQxaQCFQ5O2godgy9KEg

 

[ceb58]

Something like this:
http://www.interlockkit.com/?gclid=CNyI8OOQxaQCFQ5O2godgy9KEg

The interlock kits are great for a manual gen. set up. However K8MHZ has a situation where the gen. is the only power source available to the building.

 

[leew]

I believe that the best solution is to lift the ground-neutral bond at the generator run a 4 conductor cable to the panel and retain the neutral-ground bond there. A second ground rod should be added. This will simplify connection if commercial power becomes available. At that time a transfer switch can be added.

 

[Pierre C Belarge]

What would be the best advice I can offer the guy? I don't think there is a good way to connect a 120 volt generator designed to be used as a portable to a permanently installed entrance panel in this instance.

Our choices are:

1) No grounding of generator

2) Grounding the generator and not bonding to the premises electrode

3) Grounding and bonding, creating a parallel with the grounding conductor in the cord.

I have not read this entire thread.



I agree it is difficult to figure out how to install a portable generator to supply this setup.

 

[jwelectric]

At the risk of starting another mud slinging I think that the 2011 code clears this up a whole lot.

First the generator is defined in Article 100 as;
Ungrounded. Not connected to ground or to a conductive body that extends the ground connection.

250.34 does not require a portable generator to be connected to earth. Therefore anything that is plugged into one of the receptacles on the generator does not require an earth connection either.

If you are going to be as broad as to say that the dwelling is a cord and plugged piece of equipment then there is no requirement to connect the dwelling to earth.

If you prefer to mandate the dwelling is required to be connected to earth then this earth connection must take place at the generator or the generator must be installed as a non-SDS which has been the debate for many years if a portable generator that has devices on the frame of the generator is allowed to have a floating neutral.
My personal take on the situation, and I have talked with many, is that the portable generator is not allowed to have a floating neutral and must be used as a SDS that is ungrounded. Should grounding be required such as with a dwelling than this SDS is to be grounded at the point of the generator just as with the secondary of a transformer.

 

[weressl]

The neutral conductor is bonded to the generator frame to produce the EGC for the 120V. I do not advocate removing this bond because at some point a cord operated load will get plugged in.

The 200A panel probably has a main bonding jumper as well.
If so, current is dividing between the EGC & the neutral. I would disconnect the MAIN BONDING JUMPER in the panel, because it already exists at the generator.

See my emphasis above in bold text. The bonding of the frame will not provide an Equipment Grounding Conductor unless the frame itself is grounded, eg. connected to a grounding electrode. It provides an equipotential connection between the generator and the connected equipment, but it does not assure that there can be no potential difference between it and the ground.

Grounding assures potential equivalency between the ground and connected equipment. Bonding assures potential equivalency between the bonded items. Thus if an equipment is bonded to a grounded equipment it is effectively grounded.

 

[LarryFine]

Should grounding be required such as with a dwelling than this SDS is to be grounded at the point of the generator just as with the secondary of a transformer.

Why not anywhere between the generator and the first OCPD?

 

[Smart $]

Why not anywhere between the generator and the first OCPD?

The first OCPD is integral with the portable generator.

 

[ceb58]

Why not anywhere between the generator and the first OCPD?

The first OCPD is integral with the portable generator.

250.30 (1) is something I questioned an inspector about. Contractors that install a permanent gen. as a SDS did not bond the N-G in the gen. where the OCP was. Instead they bonded in the fusible disconnect. When I questioned this they told me it really didnt matter. Even though the gen. has a breaker they consider the gen. as the source and the disconnect as the first device.

 

[Pierre C Belarge]

. Thus if an equipment is bonded to a grounded equipment it is effectively grounded.

Weressl
Hey...we don't use this term anymore. At least not from the '08 on.

 

[Smart $]

250.30 (1) is something I questioned an inspector about. Contractors that install a permanent gen. as a SDS did not bond the N-G in the gen. where the OCP was. Instead they bonded in the fusible disconnect. When I questioned this they told me it really didnt matter. Even though the gen. has a breaker they consider the gen. as the source and the disconnect as the first device.

Under NEC 2008, 230.35 says otherwise for permanently installed SDS generators.