Generac home generator whole house?

[dm9289]

Series of questions about whole home generators given a 14KW generator.

Example 14kw generator so roughly a 240v 60amp
Conductor size 445.13A 60 x1.15=69amp so assuming 75c terminals copper#4 rated 85amps.????

Part 2 For example house currently has 120/240 single phase 200amp service.
load calc for house actual is lets say 120amps. Would you by code be required to get a larger generator if using whole house transfer switch or would it be up to user to limit their load.

 

[tom baker]

If it’s an ATS code requires that genny powers entire connected load, by load calc or by load study. Load shedding is often used to reduce connected load, ie a relay VMM drops out power to water heater.

 

[texie]

Art. 445 conductor sizing only applies from the generator to the factory mount circuit breaker. You size the conductors from the genset breaker from Table 310.16.
If this installation is using an ATS the genset must be sized to the full calculated load or have automatic load shedding. If you are using a MTS then the code allows for manual load shedding. See Art. 702.

 

[dm9289]

If it’s an ATS code requires that genny powers entire connected load, by load calc or by load study. Load shedding is often used to reduce connected load, ie a relay VMM drops out power to water heater.

Automatic so I guess it must be able to supply the 120 amp example they would need larger generator not to mention wiring.

 

[dm9289]

Art. 445 conductor sizing only applies from the generator to the factory mount circuit breaker. You size the conductors from the genset breaker from Table 310.16.
If this installation is using an ATS the genset must be sized to the full calculated load or have automatic load shedding. If you are using a MTS then the code allows for manual load shedding. See Art. 702.

Thank you and my guess is a typical generac home install does not have load shedding. I have seen whole house switches or 1 with the switch being incorporated to an emergency panel.

 

[texie]

Thank you and my guess is a typical generac home install does not have load shedding. I have seen whole house switches or 1 with the switch being incorporated to an emergency panel.

Generac has load shedding modules available for their ATSs. And just as an FYI please don't use the word emergency in any discussion about an Art. 702 (Standby) system as that term has Art 700 implications. And, yes, you could dedicate a separate ATS controlled panel to limit the load but that has draw backs as well.

 

[dm9289]

Generac has load shedding modules available for their ATSs. And just as an FYI please don't use the word emergency in any discussion about an Art. 702 (Standby) system as that term has Art 700 implications. And, yes, you could dedicate a separate ATS controlled panel to limit the load but that has draw backs as well.

Thank you and yes emergency was terrible use in this case

 

[augie47]

The vast majority of residential systems I see incorporate load shed.

 

[dm9289]

The vast majority of residential systems I see incorporate load shed.

Thank you for sharing your experience

 

[Hv&Lv]

Automatic so I guess it must be able to supply the 120 amp example they would need larger generator not to mention wiring.

Generac ATS has load shedding relays built in
Texie hit it.

 

[LarryFine]

Conductor size 445.13A 60 x1.15=69amp so assuming 75c terminals copper#4 rated 85amps.????

I would use #2 al.