Standby Generator Sizing 702.4 (b)(2)(a)

[Fred B]

Can I ask why even do a load calc when you can get peak demand from powercompany???? There an allowance for that!

None of the POCO around here give that level of information.

 

[Seven-Delta-FortyOne]

My theory for why portable backup generators pass without load calcs, is that inspectors are more comfortable with listing requirements than code. Excluding listings for equipment having wheels in 445.6 leaves inspectors with a fragmented topic, across multiple articles, which are ignored.

It states specifically that installations with manual transfer equipment are not required to handle the entire load, so no load Calc would be required.

I have yet to see a home owner with a portable generator with two wire start capability and an ATS.

 

[Josuea1990]

I posted this in another thread by mistake.

Exactly!!!!

 

[ramsy]

manual transfer equipment are not required to handle the entire load, so no load Calc would be required.

Nice point. 702.4(B)(1)
"The user of the optional stand by system shall be permitted to select the load connected to the system"

 

[tortuga]

You all probably know all this more than me, but the other thing people dont realize is generators consume a base of x gallons an hour of fuel no matter what the load, and if you have a ATS switch on while your at work and a 20kW generator is powering a tiny 100W 'away' load like porch light and oven clock its still going to consume a ton of fuel. Then when the family is home even a family of 4 might only have a 2000W load, lights, Fridge, Freezer, TV, phone chargers.. I suppose that's why they make them have a higher 3600 RPM than a 1800 RPM industrial 'prime mover'.

 

[AC\DC]

Yes but unless its for emergency back up it’s all for just end user that does not really care or want to learn

 

[Seven-Delta-FortyOne]

You all probably know all this more than me, but the other thing people dont realize is generators consume a base of x gallons an hour of fuel no matter what the load, and if you have a ATS switch on while your at work and a 20kW generator is powering a tiny 100W 'away' load like porch light and oven clock its still going to consume a ton of fuel. Then when the family is home even a family of 4 might only have a 2000W load, lights, Fridge, Freezer, TV, phone chargers.. I suppose that's why they make them have a higher 3600 RPM than a 1800 RPM industrial 'prime mover'.

Yep. Had a couple customers surprised at their increased propane bill. One of the reasons I give them all the info on fuel consumption at the start.