ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Potseal 11
Recent Posts
Permit Snafus...AHJs and Contractors Jump in
by HotLine1. 04/30/17 02:30 PM
201 volt equipment?
by bigpapa. 04/29/17 12:15 AM
Schneider LC1D09
by jraef. 04/28/17 11:05 PM
Electrode boilers question
by annemarie1. 04/27/17 01:40 PM
Why cables look like they do
by LongRunner. 04/26/17 09:36 AM
New in the Gallery:
SE cable question
Popular Topics(Views)
235,042 Are you busy
169,884 Re: Forum
163,071 Need opinion
Who's Online Now
0 registered members (), 61 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#19306 - 12/24/02 06:48 AM One more generator question??  
sparkync  Offline
Joined: Oct 2002
Posts: 817
Anyone see anything wrong with putting bigger load in a generator panel than the generator is capable of carrying,(as long as the individual circuits are protected and the inter-locks are in place for the mains, and the panel is rated for the combined load, etc....etc.....)so that the individual loads can be turned on and off as needed??? For example....say you've got your well pump on and a few lights and receptacles, and you want to heat your water up, so you turn your lights or whatever off, and turn your water heater on... Am I missing something in the code.. Seems like this should be OK since, if the generator gets overloaded, it will shut down anyway??? Thanks again for the input..I want to make sure I got everything right..I've got a couple of these jobs coming up......... Steve

Work Gear for Electricians and the Trades

#19307 - 12/24/02 07:41 AM Re: One more generator question??  
sparky  Offline
Joined: Oct 2000
Posts: 5,308
In my experience, it's a good idea to have the customer participate in sizing the critical loads.

Trying to keep it simple , i usually ask that they add up this in wattage x 1.25%

However, when they realize the $$$ involved in higher KW genny's the issue of 'juggling always arises.

There are many undesized genny's that have an all inclusive auto-T switch , simply surviving on a crap shoot re; loads on @ time of transfere.

This, as opposed to the Gen-Tran 20216 or similar models that require manual intervention probably buys one little 'code' slack, yet makes 'juggling' loads a practical option.

#19308 - 12/28/02 10:11 PM Re: One more generator question??  
Trumpy  Offline

Joined: Jul 2002
Posts: 8,211
SI,New Zealand
Do you guys, not have Maximum Demand Calculations, in the US?.
These give the fact,(called Diversity Factor),that not all of the loads will be drawing current at the same time.
We use these calcs, to size Mains and Sub-Mains, over here in New Zealand.
These Calcs, can also be applied to Gen-Sets
too, as they are the same as a Mains supply.
[Linked Image]

Let's face it, these days if you're not young, you're old - Red Green grin

#19309 - 12/29/02 04:10 AM Re: One more generator question??  
nesparky  Offline
Joined: Jun 2001
Posts: 642
The power companies use a derating factor from the calculated load of a building. This allows them to use smaller service wire than the calculated load would require if wired by the NEC. They know that electrical usage is not what the calculated load is. Different occupancies have different derating factors depending on simular loads served and thier usage history.
Check with the local utility and the AHJ before sizing the generator. Also find out from your customer what he really wants from the generator. You may be suprised how small the required generator will be. Of course if the customer has plans to add load later that should be addressed.
Good luck [Linked Image]


Member Spotlight
Belmond Iowa US
Posts: 44
Joined: August 2005
Show All Member Profiles 

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.011s Queries: 14 (0.002s) Memory: 0.7612 MB (Peak: 0.8931 MB) Zlib enabled. Server Time: 2017-04-30 22:35:34 UTC