It depends on the way you add the PDU.

If you add PDU as Aggregate Device, it will cost 1 node.

If you add it as a Aten PDU, it spends 8 nodes.

For example, if you add PE6208AV by choosing it as an Aten PDU device,  it will spend 8 nodes like the figure below.

This CC2000 totally has 150 nodes.  After adding PE6208AV, the available nodes become 142.

You could directly control the outlet of the PE6208AV.

If you add PE6208AV as an aggregate device, 8 ports PDU will only cost 1 node,  like the figure below.

For this situation,  you could just link the website of the PE6208AV, but couldn't control the outlets on/off via CC2000.