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View Full Version : Feeder Sizes and Breaker Sizing



mjdanowski
2007-07-31, 08:46 PM
Right now, Revit will size feeders for you as one big un-editable parameter for a circuit. It will also size these feeders off the breaker in which it is fed off from.
A good feature to begin with would to have Revit automatically size breakers on its current current load (no pun intended), and then have the feeders sized off the breakers.

However, the catch here really comes with customization. Feeders and breakers are one of those things which are VERY specific on the situation. There are a plethora of factors which can determine what a breaker is sized at, and what its feeder is also sized at. The ability to customize these feeders through different parameters is extremely key here to make an effective feeder schedule in Revit.
Right now, the feeder size is hard coded as one parameter which you can not edit. Ideally, three parameters - feeder, neutral and ground, which are customizable would greatly increase the viability of the sizing function.

Essentially you could have the work flow of:
1. Plop your loads in, put them on circuits.
2. Revit gives you an "initial estimate" based upon your lookup tables.
3. You can then compare through schedules, factors like voltage drop, inrush and other things which would create a difference in the breaker and/or feeder associated with it.
4. The end product becomes your reviewed feeder schedule easily taking many analysis factors in Revit into consideration.

The key is customization! Being wedged into one calculation result isn't a good thing with MEP.

JoelLondenberg
2007-08-01, 03:14 PM
Ohh if only I could vote twice. It is so hard to choose between a feature I want and beer.