Residential Generator Disconnect

[HoosierSparky]

Is a lockable disconnect required between ATS and generator? Generator has an exterior toggle switch to turn off generator. The breaker is internal to the generator case.

 

[roger]

Not required but nothing wrong with installing it.

 

[HoosierSparky]

Isn't it required by 445.18?

 

[roger]

I should have clarified, 445.18 can usually be accomplished with in the generator itself, see condition 2, that goes along with the toggle switch mentioned in your first post.

 

[anbm]

Is a lockable disconnect required between ATS and generator? Generator has an exterior toggle switch to turn off generator. The breaker is internal to the generator case.

View attachment 2559695

Will generator emergency off switch act same as local disconnect switch you clouded?

 

[Fred B]

Not sure of purpose to include that disconnect. It wouldn't serve the purpose to disable the "prime mover" referenced in 445.18(B). But secondly would or is the factory supply internal breaker filling the requirements of being "lockable" per 445.18(A). It would seem if it is not lockable a second lockable disconnect would need to be provided. If the means provided to comply with 445.18(B) is lockable it suggests that can fulfill part (A) requirements. All that said there is no reason you can't add an extra lockable disconnect.

 

[HoosierSparky]

OK, it seems a disconnect prior to the ATS is not required with the circuit breaker in the genset. The toggle on the exterior of the genset serves as a shutoff. Doesn't seem right, but it is what it is.......................................

Thanks all for your comments.

 

[qcroanoke]

OK, it seems a disconnect prior to the ATS is not required with the circuit breaker in the genset. The toggle on the exterior of the genset serves as a shutoff. Doesn't seem right, but it is what it is.......................................

Thanks all for your comments.

The toggle switch mounted on the generator does not meet the requirements off 445.18 .b. you must have a remote prime mover shutdown switch. It cant be in the generator enclosure or on the generator.

OK, it seems a disconnect prior to the ATS is not required with the circuit breaker in the genset. The toggle on the exterior of the genset serves as a shutoff. Doesn't seem right, but it is what it is.......................................

Thanks all for your comments.

The disconnect might not be required but If it is greater than 15 KW a remote prime mover shutdown is.
This is what it says:
2017 Code Language:

445.18 Disconnecting Means and Shutdown of Prime Mover.

(A) Disconnecting Means. Generators other than cord-and-plug- connected portable shall have one or more disconnecting means. Each disconnecting means shall simultaneously open all associated ungrounded conductors. Each disconnecting means shall be lockable in the open position in accordance with 110.25.

(B) Shutdown of Prime Mover. Generators shall have provisions to shut down the prime mover. The means of shutdown shall comply with all of the following:

(1) Be equipped with provisions to disable all prime mover start control circuits to render the prime mover incapable of starting

(2) Initiate a shutdown mechanism that requires a mechanical reset

The provisions to shut down the prime mover shall be permitted to satisfy the requirements of 445.18(A) where it is capable of being locked in the open position in accordance with 110.25.

Generators with greater than 15 kW rating shall be provided with an additional requirement to shut down the prime mover. This additional shutdown means shall be located outside the equipment room or generator enclosure and shall also meet the requirements of 445.18(B)(1) and (B)(2).
2020 Code Language:

445.18 Disconnecting Means and Emergency Shutdown.

(A) Disconnecting Means. Generators other than cord-and-plug-connected portable generators shall have one or more disconnecting means. Each disconnecting means shall simultaneously open all associated ungrounded conductors. Each disconnecting means shall be lockable open in accordance with 110.25.

(B) Emergency Shutdown of Prime Mover. Generators shall have provisions to shut down the prime mover. The means of shutdown shall comply with all of the following:

(1) Be equipped with provisions to disable all prime mover start control circuits to render the prime mover incapable of starting

(2) Initiate a shutdown mechanism that requires a mechanical reset

The provisions to shut down the prime mover shall be permitted to satisfy the requirements of 445.18(A) where it is capable of being locked in the open position in accordance with 110.25.
N (C) Remote Emergency Shutdown. Generators with greater than 15 kW rating shall be provided with a remote emergency stop switch to shut down the prime mover. The remote emergency stop switch shall be located outside the equipment room or generator enclosure and shall also meet the requirements of 445.18(B)(1) and (B)(2).

N (D) Emergency Shutdown in One- and Two-Family Dwelling Units. For other than cord-and-plug-connected portable generators, an emergency shutdown device shall be located outside the dwelling unit at a readily accessible location.