Service disconnect for generator

[goldstar]

I have recently run into a situation that is a new one for me. We installed a 20KW standby generator with a service entrance rated disconnect / transfer switch at the service. The generator is at the other end of the home. We ran the generator wiring in the crawl to the service disconnect. The inspector says that we need a service entrance rated disconnect at the generator as well.
No other county or locality has had this requirement. We have installed over one hundred of these in the last year with this being the only situation like this. He cites article 702.11. There is a disconnect via the generator breaker. and 702. says nothing about a service rated diasconnect.
Am i missing something?

Let's take a look at what this section of the NEC states :

ARTICLE 702
Optional Standby Systems

702.12 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,............

If the generator you're using has a readily accessible disconnect (that means not inside a lockable cover) (i.e Generac's is inside the gray panel on the right side of the unit. If you lock that gray cover then it's not readily accessible. BTW, it comes with a slide-in decvice that gives you the means to lock it. IMHO, just throw that away and don't tell your customer about it.) then

.......an additional disconnecting means shall not be required
where ungrounded conductors serve or pass through
the building or structure. The disconnecting means shall meet
the requirements of 225.36.

If you're installing a Kohler or similar unit you will have to provide an additional disconnect means within sight of the unit because access to the disconnect means for these units is under the locked cover (Some inspectors will allow you to remove the lock). Section 225.31 requires you to provide that disconnect means and 225.36 requires it to be service entrance rated.

 

[kwired]

Let's take a look at what this section of the NEC states :

ARTICLE 702
Optional Standby Systems

If the generator you're using has a readily accessible disconnect (that means not inside a lockable cover) (i.e Generac's is inside the gray panel on the right side of the unit. If you lock that gray cover then it's not readily accessible. BTW, it comes with a slide-in decvice that gives you the means to lock it. IMHO, just throw that away and don't tell your customer about it.) then
If you're installing a Kohler or similar unit you will have to provide an additional disconnect means within sight of the unit because access to the disconnect means for these units is under the locked cover (Some inspectors will allow you to remove the lock). Section 225.31 requires you to provide that disconnect means and 225.36 requires it to be service entrance rated.

Chances are your service rated disconnecting means has a padlock hasp on it effectively making it about the same as far as accessibility goes.

 

[goldstar]

Chances are your service rated disconnecting means has a padlock hasp on it effectively making it about the same as far as accessibility goes.

You are probably correct. If the inspector has an issue with one of these I would just snap off the locking tab. BTW, I was referring to discarding this optional the locking tab shown on page 13 of this manual :

http://www.electricgeneratorsdirect.com/manuals/Generac Install Manual 8-20kW-rev-6-29-2011.pdf

There is no generator disconnect inside this transfer switch :

http://www.electricgeneratorsdirect.com/Generac-Guardian-RTSY200A3/p10231.html

But this B & G model does have one :

http://www.electricgeneratorsdirect.com/Briggs-&-Stratton-71046/p2000.html

It seems like every manufacturer is making these units with no sense of what should be standard.

 

[AllCircuitsElectrical]

The A/C disconnects have a cover and are lockable .....


What's the final word on this ?


Service rated or not ?.

 

[kwired]

The A/C disconnects have a cover and are lockable .....


What's the final word on this ?


Service rated or not ?.

Never seen one that was marked as suitable for use as service equipment, and don't expect to ever find one.

 

[Gregg Harris]

I think you will find if you research CMP # 1 intention "for Readily Accessible" that your inspector is misinterpreting the lock theory as making it not "Readily Acceptable"

Staff Note for 100 Accessible, Readily (Readily Accessible) The definition of readily accessible does not preclude the use of a locked door, provided those who need ready access have a key or lock combination available to them.

 

[AllCircuitsElectrical]

Never seen one that was marked as suitable for use as service equipment, and don't expect to ever find one.

i was referring to whether or not the Breaker in the Generator is in fact a disconnect ...lol

 

[jap]

You are probably correct. If the inspector has an issue with one of these I would just snap off the locking tab.

Really ?

 

[goldstar]

Really ?

If the tab was designed such that it was necessary to hold the door closed then NO, I wouldn't snap that part off. However, I would cut or grind off the loop that allows the key to lock the cover but only in a case where the inspector was having heartburn over this issue.

 

[goldstar]

i was referring to whether or not the Breaker in the Generator is in fact a disconnect ...lol

I'm only saying this with respect to the areas I work in and what is considered acceptable here, and I cannot back this up with a Code reference. Logically speaking, if there is a fire or an emergency situation and the fire dept. has to shut off the generator, in the case of a Generac unit, the breaker inside the unlocked gray door on the right hand side of the unit is considered an acceptable disconnect means.

There is also a requirement to have a gas ball valve outdoors right before the gas line enters the unit that would shut off the gas supply and, as a result, would shut down the generator. For the life of me I don't understand why shutting the gas valve could not also be considered an acceptable disconnect means. Operating the breaker interrupts the emergency power to the building but the generator remains running. Shutting the gas valve shuts the unit down completely. Must be an electrician-plumber jurisdiction thing. Go figure.:?

 

[jap]

Because the gas valve has nothing to do with disconnecting the electrical.

 

[jap]

When I shut the gas off at the meter, my stove pilot burns until there's not enough pressure to support
the flame, I dont think thats the type of disconnecting means the code has in mind for electrical
purposes.

 

[goldstar]

Because the gas valve has nothing to do with disconnecting the electrical.

Stop and think about what you said. Is electricity still being generated if the generator is no longer running ?

 

[goldstar]

When I shut the gas off at the meter, my stove pilot burns until there's not enough pressure to support
the flame, I dont think thats the type of disconnecting means the code has in mind for electrical
purposes.

Next time you do a gen set install, start the unit then shut off the ball valve and see how fast the generator shuts down. It doesn't run for an extra 10 seconds. It shuts down immediately.

 

[jap]

I dont care how fast it shuts down, it still doesnt disconnect the conductors from the source.

 

[kwired]

I dont care how fast it shuts down, it still doesnt disconnect the conductors from the source.

True, but that may be more important for servicing. Shutting off the gas valve is likely sufficient for what firemen are after.

Then there systems with ATS that will likely crank in an attempt to restart if you shut off the gas, though any voltage produced at cranking speed should be pretty minimal.

 

[jap]

Unless they change the definition of a disconnect, a gas valve will never serve that purpose.

 

[jap]

If the fire department shows up they're more than likely going to shut the gas off at the meter if they have to.

 

[AllCircuitsElectrical]

I'm only saying this with respect to the areas I work in and what is considered acceptable here, and I cannot back this up with a Code reference. Logically speaking, if there is a fire or an emergency situation and the fire dept. has to shut off the generator, in the case of a Generac unit, the breaker inside the unlocked gray door on the right hand side of the unit is considered an acceptable disconnect means.

There is also a requirement to have a gas ball valve outdoors right before the gas line enters the unit that would shut off the gas supply and, as a result, would shut down the generator. For the life of me I don't understand why shutting the gas valve could not also be considered an acceptable disconnect means. Operating the breaker interrupts the emergency power to the building but the generator remains running. Shutting the gas valve shuts the unit down completely. Must be an electrician-plumber jurisdiction thing. Go figure.:?

I am in 100% agreement with this ....

 

[jap]

The gas valve would in fact shut the generator down but it does not disconnect the conductors from thier source, therefore
it does not meet the definition of an electrical disconnect and cannot be considered one.