Power Utilization Is Not Propagated Upstream When Connecting Devices via Intermediate Power Devices

[dmitrylomakin]

NetBox version

v4.5.2

Feature type

Change to existing functionality

Proposed functionality

In NetBox Community Edition, a power device (like PDU,UPS,ATS) correctly calculates its total power consumption in the “Power Utilization” block on the main device page.

When such a device is connected directly to a Power Panel via a Power Feed, the loading is accounted correctly (provided that maximum_draw and allocated_draw fields in the device’s Power Port are left empty).

However, when the same device is connected through an intermediate power device (for example, into a UPS outlet), the calculated consumption is not automatically propagated upstream. As a result, manual input of allocated_draw in the Power Port becomes required.

Problem Description

Current behavior works correctly in this scenario:

• Device calculates its consumption (visible in Power Utilization block).
• Device Power Port has empty maximum_draw and allocated_draw.
• Device is connected directly to a Power Feed.
• The Power Panel correctly reflects the aggregated consumption.

But in this scenario:

• Device calculates its consumption correctly.
• Device is connected to a UPS (into its Power Outlet).
• The UPS is connected upstream to a Power Feed.
• The calculated consumption is not automatically propagated to the UPS.
• The UPS does not use the child device’s calculated load.
• The administrator must manually enter the child device’s consumption into the device’s Power Port allocated_draw.

This manual process must be repeated every time:

• A device is added or removed
• Device power draw changes
• Power topology is modified

This creates operational overhead and increases the risk of incorrect power accounting.

Expected Behavior

If a device calculates its power consumption internally (via its components) and connected via Power Port to another power device (e.g., UPS):

• The parent power device should automatically account for the child device’s calculated consumption (allocated draw).
• The upstream power hierarchy (UPS → Power Feed → Power Panel) should reflect the aggregated load without requiring manual allocated_draw entry.

Use case

In real-world data center power chains:

Device → PDU → UPS → Power Feed → Power Panel

Automatic propagation is essential for:

• Accurate capacity planning
• Preventing overload conditions
• Reducing manual administrative work
• Maintaining reliable rack-level power modeling

Currently, the logic works only for direct Power Feed connections but breaks when an intermediate power device exists.

Database changes

No response

External dependencies

No response

[Chilleddaz]

I'm finding the same issue including in rack RCD/RCB which sit in between the power panel and the PDU. The RCDs have 1 input but multiple outputs.

[jeremystretch]

@dmitrylomakin this sounds more like you're describing a bug. If that's the case, please resubmit this as a bug report. And in any event, please provide some concrete examples citing real-world values for reference as this type of thing can be difficult to discuss in the abstract.

[dmitrylomakin]

@dmitrylomakin this sounds more like you're describing a bug. If that's the case, please resubmit this as a bug report. And in any event, please provide some concrete examples citing real-world values for reference as this type of thing can be difficult to discuss in the abstract.

Hi Jeremy!

It doesn't look like a bug. It is more likely that this is not taken into account in the functionality.

Easy example:

We have 2 power feeds connected with two different UPS (power ports):

As per documentation we keep should empty 'power max.draw' and 'allocated draw' for both UPS power ports to automatically transmit the power supply of devices connected to outlets to the interface:

So in case we have some PDUs connected to UPS outlet we have to add at least 'allocated draw' value for PDU's power port:

If we will keep PDU's power port with empty values, it will show empty allocated power for the upfront device (UPS):

Summary:

Allocated power for rack = 0
Power feed -> UPS (Power port with empty values) ; (Power outlet) <- PDU (Power port with empty values) ; (Power outlet) <- Device (power port with allocated draw = 100)

Allocated power for rack = 100
Power feed -> UPS (Power port with empty values) ; (Power outlet) <- PDU (Power port with allocated draw = 100) ; (Power outlet) <- Device (power port with allocated draw = 100)

[sujizeth]

Personally I would like to see the following added:

The Use Case: Modeling "Infrastructure Power" (Radials, Junction Boxes, and Lighting) rather than just "Rack Power."

The Proposed Change: Update the cable_termination logic to allow dcim.PowerPort to connect to dcim.RearPort and dcim.PowerOutlet to connect to dcim.FrontPort.

The Benefit: Enables end-to-end Power Path Tracing - through passive devices (in a consumer environment examples are Wall Sockets, Switches, Fused Spurs etc.).

I do understand that the developers may be hesitant on this due to the complexity involved in having to trace back to a Power Feed for calculations every time a cable is created / moved / deleted. Perhaps one way is to isolate the path (in case of a move to isolate both old and new) and then recalculate the Power Feed on those paths.