Accuracy of kWhr metering

[ozmosis]

We are involved in a project whereby the consultant are specifying the accuuracy of electrical meters used for monitoring onlyas +/-1%. My expereince is that monitoring is typically +/-5% accuracy and actual metering would be +/-1%. This is a building going for 5 star level NABERS (Australian Green Building) and has monitoring points throughout the building but specific areas for metering.
Has something changed in the building market forcing accuracy (and high cost) up for reasons that seem to be innappropriate?

 

[DRWeig]

Oz,

We're seeing it all over the US too. Of course, the meters themselves are no problem, it's the CTs in that accuracy class that add up to lots of extra money...

Nothing new -- except perhaps that the younger generation of specifying engineers isn't willing to accept anything as inaccurate as ±5%. I'm even seeing specs for 6-digit displays for real-time air flow rates. C'mon, we can't even measure that stuff with two-digit accuracy in buildings!!

Good on ya,

Goober Dave

 

[MintJulep]

It's possible there there is legitimate need. Perhaps the monitoring points could become metering points in the future.

More likely however is that no one has given it much thought, or that the consultant was responding to a last-minute owner request and simply cut-and-pasted from a past spec.

 

[ozmosis]

Mint
I think it is the latter.
We see more and more specs that have tighter tolerances, because some folk think this will be 'better'. Sure it will, as long as they wish to pay for it.