Cape Town
Grid quality in Constantia
clean supply over the last 30 days, measured continuously at 6 inverters in Constantia.
Long term to short term
One number tells you nothing about direction. These are the same measurement over seven windows, longest first — so a feeder that is getting worse looks different from one that has always been poor.
| Window | Clean supply | Out of spec | Off | Outages | Monitoring uptime | Measured by |
|---|---|---|---|---|---|---|
| year | 97.8% | – | 2.2% | none | 76.1% | inferred |
| 3 months | 99.9% | – | 0.1% | none | 84.8% | inferred |
| 30 days | 100.0% | – | 0.0% | none | 39.2% | inferred |
| 2 weeks | 89.1% | 0.0% | 10.9% | none | 57.7% | measured |
| 7 days | 100.0% | 0.0% | 0.0% | none | 72.8% | measured |
| 3 days | 100.0% | 0.0% | 0.0% | none | 97.5% | measured |
| 24 hours | 100.0% | 0.0% | 0.0% | none | 97.2% | measured |
Out of spec means the supply was live but outside the limits an inverter will synchronise to — the power is on, and it is not usable. It is measured only where the row says measured; inferred rows are derived from power flow, which cannot see it. – means we do not have the figure, never that it was zero.
Confirmed outages
An outage is only counted when several inverters in Constantia lose the grid in the same hour. One inverter going quiet is not an outage — it is one inverter going quiet, and counting it as an outage is the mistake this page exists to avoid.
No confirmed outage in Constantia in the last 90 days.
How this is measured
- It is measured, not modelled.
- Every figure here comes from inverters in Constantia reporting every few minutes — not from a utility schedule, a load-shedding app, or anyone's estimate. Two methods sit behind them, and each row says which it used. Measured rows are our own reading of the grid frequency and voltage the inverter is seeing. Inferred rows come from recorded power flow, which shows when the grid was gone but cannot show when it was present and out of spec. We do not average the two together.
- Never fewer than 3 homes.
- A suburb is only published once at least 3 separate systems in it are reporting. Below that, a "suburb figure" would be one household's electricity supply with a suburb's name on it, so we do not publish one. No address, no name and no individual system's readings appear on this page or in the numbers behind it, and any owner can ask to be left out of the aggregate entirely.
- Why the older windows have no "out of spec" figure.
- Our own frequency and voltage reading covers roughly the last 2 weeks. Further back than that we can tell you whether the power was there, but not whether it was usable — so those rows show a dash rather than a zero. That history builds from here: every week the measured windows reach further.
Is your street on here?
Constantia is on this page because 6 people shared their inverter with us, read-only. It costs nothing, we never get your password, and you get your own system benchmarked against your neighbours' in return.
Figures rebuilt 3 hours ago. Times shown are South African time.