Residential Generator

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shaw0486

Senior Member
Location
baltimore
Hey guys,
I am a commercial contractor. However I am about to install a generator on my house. Tell me if this installation seems lagit to you all.

The generator is 10 KW with a 50amp breaker built into it.

I am installing a 100amp MCB ATS. Feeding it from a 50a breaker fromt he normal power panel and from the generator.
I am installing a 100a MLO panelboard. does anyone see any issues with this being MLO? Is there anything else that anyone out there come up against that maybe an issue?
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
shaw0486 said:
Hey guys,
I am a commercial contractor. However I am about to install a generator on my house. Tell me if this installation seems lagit to you all.

The generator is 10 KW with a 50amp breaker built into it.

I am installing a 100amp MCB ATS. Feeding it from a 50a breaker fromt he normal power panel and from the generator.
I am installing a 100a MLO panelboard. does anyone see any issues with this being MLO? Is there anything else that anyone out there come up against that maybe an issue?
Click to expand...

What is the calculated load that will be on the gen.? You must follow 702.4 (B) 2 a or b (2011)
Automatic Transfer Equipment.​
Where automatictransfer equipment is used, an optional standby systemshall comply with (2)(a) or (2)(b).(a) Full Load. The standby source shall be capable ofsupplying the full load that is transferred by the automatictransfer equipment.(b) Load Management. Where a system is employed thatwill automatically manage the connected load, the standbysource shall have a capacity sufficient to supply the maximum​
load that will be connected by the load management system.
 
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shaw0486

Senior Member
Location
baltimore
just a 30 amp ac, the refrigerator, furnace ignitor and some minor lighting and receptacle loads. Furnace, range and water is NG.
 
tkb

tkb

Senior Member
Location
MA
ceb58 said:
It all sounds good. You will need to install a disconnect between the gen. and ATS per 225.31 & 32
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There are people that consider the breaker on the generator to comply with this requirement.
See also 702.12
 
R

Robert Hutcherson

Member
Location
Pembroke Pines,Florida
Residential Generator

Another idea that would provide load management flexiblity, would be to install a manual transfer switch in lieu of an ATS between the service main and the main panel. This allows management to limit the load but be ables you to use appliances that using an ATS would not allow. Install a toggle switch adjacent to the MTS to start the generator. Just an idea for using a generator that is smaller than would be required for "whole house" option.

Goo Luck.
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
tkb said:
There are people that consider the breaker on the generator to comply with this requirement.
See also 702.12
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All ready in a discussion on this point in another thread. You would be hard pressed to have a 10Kw residential unit meet 702.12.
 
tkb

tkb

Senior Member
Location
MA
jap said:
What does 702.12 state?

dont have my book with me.
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702.12 Outdoor Generator Sets​

Where an outdoor housed generator set is equipped with areadily accessible disconnecting means located withinsight of the building or structure supplied, an additionaldisconnecting means shall not be required where ungroundedconductors serve or pass through the building orstructure. The disconnecting means shall meet the requirements of​
225.36.


I don't see why this wouldn't apply to residential generator.​
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
tkb said:
702.12 Outdoor Generator Sets​


Where an outdoor housed generator set is equipped with areadily accessible disconnecting means located withinsight of the building or structure supplied, an additionaldisconnecting means shall not be required where ungroundedconductors serve or pass through the building orstructure. The disconnecting means shall meet the requirements of​

225.36.


I don't see why this wouldn't apply to residential generator.​
Click to expand...

The disconnect on the majority of these units are behind lockable covers which violates the with in sight and accessible rule. Even at that the disconnects on these units do not meet 225.36 "suitable as service equipment".
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
jumper said:
"You go first."

"No, you go first."

"No, you go first."

"No, you.........":D:D:D
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I stated why in post #10. We have over 180 generator units throughout the state. They range from 25Kw to 100Kw. There is not one of them that the OCP/disconnect that is built into the gen. states "suitable for use as service equipment" along with the fact that you can see the generator but which locked door is the disconnect behind?
The type unit the OP is installing is not much bigger than a large suitcase with a lockable hinged lid. Under this lid is the disconnect, the same disconnect you cannot see. The same disconnect that doesn't meet 225.36
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
ceb58 said:
I stated why in post #10. We have over 180 generator units throughout the state. They range from 25Kw to 100Kw. There is not one of them that the OCP/disconnect that is built into the gen. states "suitable for use as service equipment" along with the fact that you can see the generator but which locked door is the disconnect behind?
The type unit the OP is installing is not much bigger than a large suitcase with a lockable hinged lid. Under this lid is the disconnect, the same disconnect you cannot see. The same disconnect that doesn't meet 225.36
Click to expand...

Curtiss, t'was a joke towards Jap.

I already knew you were correct. You know generators, of that, there is no doubt in my mind.
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
shaw0486 said:
Where does it say that the disconnecting mean has to be suitable for service equipment?
Click to expand...

The lively debate is over this
702.12 Outdoor Generator Sets.​
​
​
​
​
Where an outdoor housedgenerator set is equipped with a readily accessible disconnectingmeans located within sight of the building or structuresupplied, an additional disconnecting means shall not be requiredwhere ungrounded conductors serve or pass throughthe building or structure. The disconnecting means shall meet​
the requirements of 225.36.

Then look at the last sentence.


225.36 Suitable for Service Equipment.​
​
​
​
​
The disconnectingmeans specified in 225.31 shall be suitable for use as​
service equipment
 
kwired

kwired

Electron manager
Location
NE Nebraska
Must be new section in 2011 NEC. I don't have a 702.12 in 2008, and did not see anything else with similar requirement.

I will not argue that it must be suitable for use as service equipment because it does say that, my question is why, and why would it be a violation for it to be behind a locked door? The service equipment in general can have a lock on the door or be located in a room with a locked door if the owner desires.
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
kwired said:
Must be new section in 2011 NEC. I don't have a 702.12 in 2008, and did not see anything else with similar requirement.

I will not argue that it must be suitable for use as service equipment because it does say that, my question is why, and why would it be a violation for it to be behind a locked door? The service equipment in general can have a lock on the door or be located in a room with a locked door if the owner desires.
Click to expand...

702.11 is the 2008 art. We are not talking about equipment in general. 702.11 or 12 is speaking directly to outdoor housed generator units only and nothing else.

generator set is equipped with a readily accessible disconnecting means located within sight of the building or structure supplied
Click to expand...
 
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