'smart' meters, contactor or SCRs inside?

[wireguru]

The new smart meters that can be turned on and off remotely by the utility, do these have a mechanical contact inside, or are they using SCRs or Triacs to switch the power? How reliable are these things?

 

[mivey]

The new smart meters that can be turned on and off remotely by the utility, do these have a mechanical contact inside, or are they using SCRs or Triacs to switch the power? How reliable are these things?

The pics I saw had a device that resembled a breaker.

 

[la2151]

smart meters

smart meters

PG& E in calif has been having problems with some of there smart meters.Had a customer thad had to have theirs changed out as it was being really noisy.

 

[dbuckley]

I dont know about smart meters, but the radio switches our utilities use have contactors in them. I'd have thoiugh the chances of the switching element being an SCR (especially in the USA with 120V so twice the current) is very low.

 

[ELA]

I have no first hand knowledge and have also wondered about this.
I would expect a contactor rather than triacs so as not to waste power in the triac voltage drop at service level currents?

 

[wireguru]

I can see them using SCRs, Triac, Solid state relay, etc in these. The cost has come down greatly (especially when using noname chinese components -just sayin). I wonder if a 200a mechanical contactor would even fit in one of these things... I hope theyre not solid state, sometimes these things have a failure mode where one scr will fail closed and the resulting power is half wave.

 

[Jraef]

I know this is an old thread, but it came up on a search about meters and I felt compelled to chime in.

No SCRs. SCRs have to dissipate 1-1/2W of heat per running load amp, and to control 240V, they would need 4 SCRs. So for a potential 160A continuous load on a 200A meter, you are looking at 2,880W of heat. You would need one heck of a heat sink for that, and who pays for that wattage?