I have two projects both consist of 1000 amp three phase services. There are two EE's one for each project. One engineer says I need a disconnect for a portable generator the owner will supply. The other engineer says I do not need a disconnect.Both buildings have the same owner who would prefer to just hook up to the transfer switch. Do I need a disconnect for a portable generator? Any code refrence would be appreciated.
generator disconnect
- Thread starter friday
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ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: generator disconnect
I will guess that these are Article 702 generators. Does the portable gen have a set mounted disconnect? If so where is it located?
I will guess that these are Article 702 generators. Does the portable gen have a set mounted disconnect? If so where is it located?
Re: generator disconnect
Ron,
The generator has not been purchased yet , from my knowledge. Asked first EE and he replied, the equipment must be protected , what if they brought in a larger generator than the survice is rated for? this is why we need a disconnect. My reply was the generator isnt going to MAKE the building consume energy.The second EE replied ( the one without the disconnect) we cannot go by " what if" senerios.
Ron,
The generator has not been purchased yet , from my knowledge. Asked first EE and he replied, the equipment must be protected , what if they brought in a larger generator than the survice is rated for? this is why we need a disconnect. My reply was the generator isnt going to MAKE the building consume energy.The second EE replied ( the one without the disconnect) we cannot go by " what if" senerios.
pierre
Senior Member
- Location
- Westchester County, New York
Re: generator disconnect
1000 amp 3-phase service... a portable generator...
Are you sure it is a "portable generator"
These larger generators generally have some means of disconnect built into the unit.
1000 amp 3-phase service... a portable generator...
Are you sure it is a "portable generator"
These larger generators generally have some means of disconnect built into the unit.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: generator disconnect
I've had Section 225.31 and those that immediately follow, stated as requirement for a set mounted disconnect or one at the building, depending on locations.
I believe that 225.31 comes into play for many folks that will interpret the intent of the 702 sections of code to somewhat match the requirements of 701.11(B)(5).
I've had Section 225.31 and those that immediately follow, stated as requirement for a set mounted disconnect or one at the building, depending on locations.
I believe that 225.31 comes into play for many folks that will interpret the intent of the 702 sections of code to somewhat match the requirements of 701.11(B)(5).
pierre
Senior Member
- Location
- Westchester County, New York
Re: generator disconnect
Ron
I stayed clear of mentioning that section... I am glad you had more courage than me. I mention that around here, and contractors get really mad... they do not like that new requirement.
[ February 07, 2006, 10:01 PM: Message edited by: pierre ]
Ron
I stayed clear of mentioning that section... I am glad you had more courage than me. I mention that around here, and contractors get really mad... they do not like that new requirement.
[ February 07, 2006, 10:01 PM: Message edited by: pierre ]
- Location
- Lockport, IL
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- Semi-Retired Electrical Engineer
Re: generator disconnect
However, the key question is not whether the generator requires a disconnecting means. It does not. That is, you are not trying to disconnect the generator from its power source. Rather, the key question is whether the conductors entering the building require a disconnecting means.
Then you can reply back that a disconnect does not provide such protection. If the EE wants protection, then we should be taking about "fused dicsonnects" or breakers.
However, the key question is not whether the generator requires a disconnecting means. It does not. That is, you are not trying to disconnect the generator from its power source. Rather, the key question is whether the conductors entering the building require a disconnecting means.
Re: generator disconnect
I just posted a similar question - I think your engineers got the same vendor information that I got - or one of them did. The question is whether or not the generator breaker, which is inside of the generator enclosure, which is probably locked, is readily accessible. It is also whether or not the code article 700.11, 701.11 or 702.11 is saying that the generator is within site of the building or whether the generator disconnect is within site of the building.
I received information from one of the generator manufacturers stating that there had to be a disconnect on the outside of the building anytime an outdoor generator was installed.
The question is whether the article is trying to say, 'Hey guys, a generator doesn't have the same strict requirements as other services' or whether the article is trying to set up different requirements for a generator so that someone could disconnect a burning generator without having to run into a dangerous situation. It is my impression that it is the former. But, I have been told a number of times that it was the latter.
If the disconnecting means is 'service disconnecting means' then it can be inside the building - which certainly eliminates the possibility of this code reference trying to provide a sort of 'emergency power off.'
Is there another reason?
I just posted a similar question - I think your engineers got the same vendor information that I got - or one of them did. The question is whether or not the generator breaker, which is inside of the generator enclosure, which is probably locked, is readily accessible. It is also whether or not the code article 700.11, 701.11 or 702.11 is saying that the generator is within site of the building or whether the generator disconnect is within site of the building.
I received information from one of the generator manufacturers stating that there had to be a disconnect on the outside of the building anytime an outdoor generator was installed.
The question is whether the article is trying to say, 'Hey guys, a generator doesn't have the same strict requirements as other services' or whether the article is trying to set up different requirements for a generator so that someone could disconnect a burning generator without having to run into a dangerous situation. It is my impression that it is the former. But, I have been told a number of times that it was the latter.
If the disconnecting means is 'service disconnecting means' then it can be inside the building - which certainly eliminates the possibility of this code reference trying to provide a sort of 'emergency power off.'
Is there another reason?
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