The observed reading can not be related to the consumers installation as this is isolated by the RCCB being turned off.    It cant be related to the DNO equipment as the cut out fuse was removed.

That leaves the electricity meter. The observed reading could be the DC resistance of the "voltage" coil in the kwh meter as this is connected across the supply. This coil is highly inductive and the AC impedance will be much higher than 943 ohms.

I can't say it's a test I've attempted - but many modern RCDs will have electronics inside that will need to draw power from the supply when the RCD is switched on - so some measurable resistance on one or other set of terminals doesn't surprise me. <1k feels a bit low, but often d.c. meter reading aren't representative of how the circuit will behave on mains a.c. (e.g. once capacitors are charged up), so I wouldn't be unduly worried if there are no other negative symptoms.

Some seem to power the electronics across the incoming terminals (so they're out of circuit from the load when the RCD is open) - handy for insulation testing downstream - others seem to use the outgoing terminals (which is helpful if you're testing the supply side - e.g. submains). And of course many designs allow connection either way around anyway.

   - Andy.

how hot is it running - 1000 R would pass about quarter of an amp - so if resistive, about 60 watts dissipation. I suggest that unless something is on fire, it is not that.

I'm with broadgage -if the meter is the old spinning disk type, then the voltage shunt coil will be some henries, but to DC may well give a surprisingly low resistance.

Interesting. Seems the meter is chief suspect, it is an old spinning one. I was measuring resistance across the terminals because there appeared to be a strand of something across the them that looked like copper, and I thought it can’t be something conductive!. Turned out to be a thread of cotton or something similar.