Tweet
DB Monitoring, Mains sensing
Hi,
I'm highly experienced with regarding electronics engineering and working with mains voltage circuits for devices that plug in to wall outlets; but unfamiliar what standards may apply for relevant DB connections.
If any of you are familiar or can point me in the right direction, that would be much appreciated!
I've seen "Smart DB's" around, for example ACDC carries a product that does this, with WiFi and so on.
But I'm not looking for something so elaborate and costly.
I simply want to do voltage sensing
Ideally sensing at
* Mains switch output
* Earth leakage output
* Breaker output
The actual sensing circuit will be very safe from a technical perspective, but I'm unfamiliar with how standards compliant this would be.
So what I'm wanting to know is things like having an inline cable-mount fuse coming from an isolator or breaker. Hanging freely, is that okay, does it need to be mounted in a special way, etc?
So the circuit for each sensor would be as follows
Live > 50mA 250V Fuse > Resistors (rated for 250V) > Optical isolator with isolation voltage of 5000V
On the output side of the optical isolator would be low-voltage digital monitoring circuitry.
The optical isolator's connections will be encased in high-temp epoxy to prevent accidental connections due to solder joints hypothetically breaking.
So the "dangerous" part of this circuit is length of live wire from the source to the fuse. That wire can be as short as possible, around 5~10cm. And to a lesser extent the neutral and fused live wires leading to the mains-side of the optical isolator circuit. Those wires can be reasonably short, around 15-25cm. The enclosed optical isolator circuit can be quite small. But then the next question would be: Does it need to be mounted in a fixed position inside the DB, or just hang on the wires. It will only weigh a few grams.
In my opinion the above is 100% safe, however I anticipate that there could be various issues regarding standards, legality or costly testing required and so on?
See attached images.
An even safer option would be LED's that shine into fiber optic cables, and those fiber optic cables travel out of the DB, 1 meter, then connect to the digital monitoring device. That way there isn't even a hypothetical potential electrical connection between the DB and the low voltage monitoring device. That's a bit more of a hassle.
Assuming that there are too many problems with doing this, the other way to do this would be to simply have standard SANS pilot lights for every voltage to be monitored, and a webcam pointed at the pilot lights. But then automated monitoring of those pilot lights is a bit more of a hassle to implement.
I'm highly experienced with regarding electronics engineering and working with mains voltage circuits for devices that plug in to wall outlets; but unfamiliar what standards may apply for relevant DB connections.
If any of you are familiar or can point me in the right direction, that would be much appreciated!
I've seen "Smart DB's" around, for example ACDC carries a product that does this, with WiFi and so on.
But I'm not looking for something so elaborate and costly.
I simply want to do voltage sensing
Ideally sensing at
* Mains switch output
* Earth leakage output
* Breaker output
The actual sensing circuit will be very safe from a technical perspective, but I'm unfamiliar with how standards compliant this would be.
So what I'm wanting to know is things like having an inline cable-mount fuse coming from an isolator or breaker. Hanging freely, is that okay, does it need to be mounted in a special way, etc?
So the circuit for each sensor would be as follows
Live > 50mA 250V Fuse > Resistors (rated for 250V) > Optical isolator with isolation voltage of 5000V
On the output side of the optical isolator would be low-voltage digital monitoring circuitry.
The optical isolator's connections will be encased in high-temp epoxy to prevent accidental connections due to solder joints hypothetically breaking.
So the "dangerous" part of this circuit is length of live wire from the source to the fuse. That wire can be as short as possible, around 5~10cm. And to a lesser extent the neutral and fused live wires leading to the mains-side of the optical isolator circuit. Those wires can be reasonably short, around 15-25cm. The enclosed optical isolator circuit can be quite small. But then the next question would be: Does it need to be mounted in a fixed position inside the DB, or just hang on the wires. It will only weigh a few grams.
In my opinion the above is 100% safe, however I anticipate that there could be various issues regarding standards, legality or costly testing required and so on?
See attached images.
An even safer option would be LED's that shine into fiber optic cables, and those fiber optic cables travel out of the DB, 1 meter, then connect to the digital monitoring device. That way there isn't even a hypothetical potential electrical connection between the DB and the low voltage monitoring device. That's a bit more of a hassle.
Assuming that there are too many problems with doing this, the other way to do this would be to simply have standard SANS pilot lights for every voltage to be monitored, and a webcam pointed at the pilot lights. But then automated monitoring of those pilot lights is a bit more of a hassle to implement.
Attached Files