Novedge Pulse™ — David Butts

Ran into this one recently...we have a project with a new user that is adding devices to circuits. In the project she's working on, we have number of poles and voltage assigned as a parameter, but somewhere along the line added a phase parameter that was also equal to the number of poles...which, if you're the electrical designer, you know is wrong.So here's my simple explanation, with a little help...the Number of Poles in a circuit relate to the physical slot locations on a panel. The Phase refers to the A/B/C branches of a panel. Phase is a product of typical AC (or alternating current). Without going into great detail, know that Revit support single phase (panels with A/B branches, just like your house) or 3 phase (A/B/C - most commercial applications).With electrical connections, you'll have these types of connections:120/240 - these are single phase panels, with two poles - most commonly found in residential120/208 - a three phase panel, more common in commercial applications. This type of panel also requires 4 wires to use all three slot sizes, from 1-3.120V is common in the US, but not common in other areas, such as Europe.120V - A single phase, single pole Circuit - unless it's a GFI circuit, which could be single pole but 2 phase208V/240V - typically a 2 pole, 2 phase circuit, but also could be three phase (for example, in the event of a 208V GFI Circuit)Higher voltage panels for commercial and industrial applications are typically 277/480, indicating a two to three pole circuits, with 3 or 4 phases. 460-480V devices require a three pole, 3 or 4 phase circuit, depending on the power type.In my simple little, non-electrical mind, it's a bit confusing, but from Revit, it's pretty straight forward.If something is 120v, set the number of poles to 1. This will take up one slot in the panel, or one "circuit"If something is 208v 240v, or 277v, set the number of poles to 2. These circuits take up two slots in the panel. Since the voltage is a range, 208 or 240 are considered low voltage, while 277 is used in higher voltage systems. Even more confusing, some motors are 230, three phase motorsFor 480V, set the number of poles to 3. This takes up three slots, and can only be used in a panel that is defined as a 3 or 4 wire, 3 phase panel.These are all set under electrical settings, for the distribution systems:Revit requires that the proper combination of poles and voltage in order to add something to a circuit. There are two configurations for any type of a three phase panel - Delta, which doesn't include a neutral branch, and Wye, which does include a neutral.Revit only recognizes single or three phase systems when you define your distribution system. For example, you might have a device or circuit, that requires 208v service but is single phase - you still have to assign the number of poles to 2. Otherwise, it can't be connected to a panel.For more information, talk to a more reliable source than me - your local electrical engineer. Hope this helps - if anyone wants to add to the conversation, knock yourself out!thanks - David B [more...]