While trading some emails with
Aaron Maller recently he mentioned that he observed that he could create circuits for nested shared electrical families. I don't recall Autodesk publicly taking credit for adding or allowing this behavior but I find that it has been possible as far back as the 2012 release. I'd try earlier releases too but I don't have them installed anymore. Since I started preparing this post I've discussed it with
Jose Fandos and he confirmed that it is possible in 2011 too.
I'm a bit frustrated because I thought I tried to explore this possibility a couple years ago while making some electrical content. Rather than dwell on what I thought wasn't possible I'll focus on what IS possible instead.
Experience tells us there are many components that have a variety of options or configurations that can prove difficult to include connectors in, for example a boiler with its electrical panel available either on the right side OR the left side. When a single connector is placed we are inclined to placing it in the "middle" so we can "connect" it to a power supply. That's easier to accept for electrical connections but not as easy for piping or duct.
When the connectors are native, placed directly in a family, it isn't possible to put two connectors in place but disable one or the other. Revit sees both even if we only use one of them in the project. With two connectors in the model we can define where connections take place more accurately but ultimately we end up with one valid connector (connected) and another lurking as "unassigned" within the system browser. It might not a big deal but Revit's developers encourage to assign everything to systems so this approach means there will always be some we can't assign properly.
If the connector is part of a nested shared family and this nested family is assigned a Yes/No parameter to control its Visible parameter we gain control over not only when it is visible but also whether or not Revit sees a valid connector in the host family when it is loaded into a project. This is a crude example with connectors for pipe, electrical and data circuits, offering a conceptual right and left configuration.
When I use a yes/no parameter to control the visibility of the nested families it is interesting to find that the system browser responds to their condition. As can be expected Revit will delete a circuit or system associated with a nested connector if we choose to turn it off.
So far I find that I can create systems, connect pipe and duct, draw wires as well as tag the nested shared families. This means that it may be a bit easier now to define a component that has multiple circuits. This can help counter the limitation that a family can only report circuit information (in a tag) for the primary connector when multiple connectors are in a family.
It isn't perfect...naturally.
Nested families with connectors are harder to see and therefore are harder work with. The connectors are only visible when you hover over the location where they are when you are using the appropriate tool, like duct, pipe or wire. That also means we can't use the convenient right click "create pipe/duct/wire" options because we can't see the connectors.
It may also confront us with a need for sub-categories for connector geometry, not for the connectors themselves but any forms we use to host them. It can be easier to find the connectors if we can see the hosting forms but we may not want to see them in every kind of view.
Ultimately I think it's worth exploring further. Perhaps you'll agree?