residential generator installations

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Jeffnmoe@comcast.net

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I have recently come across several residences which have had standby gens . installed . All of the units have a disconnect inside a locked generator cabinet that is only accessible if you have the key. The load side of this disco. feeds directly to this neat little box which is normally mounted on the residence ,looks like a disconect but it is only a terminal box where both the grounded and ungrounded conductors are terminated. In my eyes,shouldnt there be a readily accessible disco.,not one in a locked cabinet ,that can be used by anyone needing to diconnect the generator from the house in a hurry? What about a label indicating that the residence has a standby power source to warn emergency personel or power company personel of its location? Anyone?
 
I believe you are correct in the requirements. Art. 702 if I am not mistaken. The breaker on the generator probaly quallified at the time of install, but I am not sure what happens when the enclosure is later locked. I have rarely seen labels on generator job sites. Some transfer switches are labeled/lit as indicators, but they are getting fewer and fewer.
 
I see nothing in 702 that would require a disconnecting means outside.

These generators are often outside and supply a separate building or structure. That being the case 225.31 requires a disconnecting means and 225.32 gives us the acceptable locations.

The disconnecting means can be inside or outside the building it serves and must be 'nearest the point of entrance'.

However, if an outdoor genset has a readily accessible disconnect within sight of the building it serves IMO 702.11 allows that disconnecting means to take the place of the one required by 225.31.
 
I'm with Bob, the locked door does not mean that the disconnect is not readily acccessible.
 
Readily Accessible

Readily Accessible

According to the Art.100, Accessible --Admitting close approach;not guarded by locked doors,elevation or other effective means.




Readily Accessible-- Capable of being reached quickly for operation.


My main concern is this ,a home catches fire and the local FDP arrives. The home owners are not present and the FDP has killed power to the home and now the generator starts and supplies power to the once de-energized home.Now the first responders may be entering a home which they believe to be de-energized. If the disconnect is under lock and key they will need to destroy the generator cabinet to access it ,losing precious time . A simple non-fused disconnect mounted on the home instead of the typical terminal box can save not only the FDP precious time but also the home owner the expense of a new generator cabinet. Proper labeling of the meter fitting electrical panel and the disconnect can save not only time but maybe a life.
 
700.9,701.9,and 702.8 state that signage must be placed at service equipment stating that there is an alternate power source and where it is located. As for readily accessible 2005 handbook goes on to say that readily accessible does not preclude of a locked door. Fire fights have an ax I am sure can take care of the lock.
 
Just curious - why would someone lock their genset cabinet ? To prevent an unauthorized person from getting inside ? If they lock that then why not lock the disconnect cabinet too and make the installation completely vandal-proof ? When the FD pulls up to a burning structure, if the genset cabinet isn't locked they can shut off the breaker inside and close the fuel source to stop the generator, unless that's locked also. Well, at least that way they'll be happy no one was able to break into the genset cabinet or vandalize their system because that will be the only thing left after their residence burns down.

My point is that if someone wanted to vandalize your house they don't have to start with the genset so why lock the cabinet ?
 
iwire said:
However, if an outdoor genset has a readily accessible disconnect within sight of the building it serves IMO 702.11 allows that disconnecting means to take the place of the one required by 225.31.
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Bob, would this disconnect mentioned in 702.11 have to comply with 225.36?
 
Mike see 702.3 "Except as modified by this section ...."
The disconnect requirement has been modified
 
jwelectric said:
Would the disconnect allowed in 702.11 be required to be rated as service equipment?
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It does not say that it must.

I will admit it reads like one hand does not know what the other is doing.
 
Jeffnmoe@comcast.net said:
My main concern is this ,a home catches fire and the local FDP arrives. The home owners are not present and the FDP has killed power to the home and now the generator starts and supplies power to the once de-energized home.
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Why do you feel the generator disconnect must be 'more accessible' than a service disconnect?

The majority of service disconnects are inside the building behind locked doors.

Regardless of how you may feel it does not appear the NEC is going to back you up.
 
Mike, not as far as I can tell it says "Where an outside housed generator set is equipped...." which I take to mean the disconnect equipped was not supplied by me..rather the folks who produced the generator set provided it.
Mike , I'm wondering what your take on 702.3 in regard to the disconnect requirement?
 
M. D. said:
which I take to mean the disconnect equipped was not supplied by me..rather the folks who produced the generator set provided it
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Good point, I had not noticed that.

The IAEI 2005 "Analysis of Changes" portrays it that way as well.
 
jwelectric said:
iwire said:
It does not say that it must. I will admit it reads like one hand does not know what the other is doing.
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jwelectric said:
Would the disconnect allowed in 702.11 be required to be rated as service equipment?
Click to expand...

Well this is something that needs to be answered, don?t you think?

225.31 Disconnecting Means.
Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.

225.36 Suitable for Service Equipment.
The disconnecting means specified in 225.31 shall be suitable for use as service equipment.

445.18 Disconnecting Means Required for Generators.
Generators shall be equipped with disconnect(s) by means of which the generator and all protective devices and control apparatus are able to be disconnected entirely from the circuits supplied by the generator except where both of the following conditions apply:
(1) The driving means for the generator can be readily shut down.
(2) The generator is not arranged to operate in parallel with another generator or other source of voltage.

702.3 Application of Other Articles.
Except as modified by this article, all applicable articles of this Code shall apply.

702.11 Outdoor Generator Sets.
Where an outdoor housed generator set is equipped with a readily accessible disconnecting means located within sight of the building or structure supplied, an additional disconnecting means shall not be required where ungrounded conductors serve or pass through the building or structure.

Accessible, Readily (Readily Accessible). Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, and so forth.

The way that I am reading these articles the permission given in 702.11 will require that the disconnect be rated as service equipment and to be readily accessible. 702.3 only modifies the disconnect not the rating required in 225.36.

The transfer switch will need to be rated as service equipment if the disconnect allowed in 702.11 is not rated as service equipment.

What do you all think?
 
jwelectric said:
What do you all think?
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I think now that Marc pointed out it is a factory disconnect switch that all bets are off. 225.31, 32, 36 and 39 are all out the window.

I know it never says that.....
 
We install Generac gensets. As of last year, their SE rated ATS comes with a generator main breaker, as well the main breaker for the system, so the genset can be turned of at the ATS as well as the genset. But that still does not prevent locking. If one is going to lock the genset, there is a good chance they will lock the equipment as well.:rolleyes:
 
To my way of thinking, if you have to get past a lock, in order to operate a disconnect, then the disconnect can not be ?reached quickly for operation.? So it?s not readily accessible.

But I don?t think the purpose of the disconnecting means to a structure is to permit the structure to be rapidly de-energized in an emergency. Rather, the purpose is to allow it to be completely turned off, so that maintenance can be safely performed.

I didn?t see anything in Mike?s list of quotations that contradicts this viewpoint. Does anyone else?
 
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