What sensor to choose to find the shape of current

[Abdul Wali]

I want to choose a sensor which can sense the current flowing from the electricity meter of the residential houses, the sensor should be able to sense the shape of electrical signal each second that how it looks like. can some one help me with that ?

 

[anorlunda]

The sensor is a shunt resistance. Only a licensed electrician can install one. Do not attempt to do it yourself.

 

[Abdul Wali]

The sensor is a shunt resistance. Only a licensed electrician can install one. Do not attempt to do it yourself.

thanks for your reply, so what is the name of the sensor and what do you mean by shunt resistance sensor ?

 

[anorlunda]

thanks for your reply, so what is the name of the sensor and what do u mean by shunt resistance sensor ?

If you don't know that answer, then you are not qualified to go forward with that project.

 

[berkeman]

I want to choose a sensor which can sense the current flowing from the electricity meter of the residential houses, the sensor should be able to sense the shape of electrical signal each second that how it looks like. can some one help me with that ?

Can you say more about why you want to do this? As anorlunda points out, you may need a licensed electrician to help you with this, depending on what you are trying to do. Are you the homeowner?

 

[Windadct]

There are two main sensor types for current, Shunt Resistor - is installed in series, that is inline with the current path, the other is a Current Transformer ( or a related Hall Effect) - there are others. Since both of these require you to access the individual cables (conductors) of the Mains ( residential feed) - it is a job for a proerly qualified individual. Also note - to combat theft of electricity the actual electrical meters ( external ) are pretty hardened, making it nearly impossible to measure these values "at the meter", you can not walk up to the meter and get this data..
These are JUST the sensor - you then need an instrument to interpret the signal and provide you with the data as you have asked for it. For example a sensor does not tell you "how it looks"... that is the instrument's job.

Based on your language - it seems you are suspecting the utility, or the meter itself to be at fault.

 

[Abdul Wali]

There are two main sensor types for current, Shunt Resistor - is installed in series, that is inline with the current path, the other is a Current Transformer ( or a related Hall Effect) - there are others. Since both of these require you to access the individual cables (conductors) of the Mains ( residential feed) - it is a job for a proerly qualified individual. Also note - to combat theft of electricity the actual electrical meters ( external ) are pretty hardened, making it nearly impossible to measure these values "at the meter", you can not walk up to the meter and get this data..
These are JUST the sensor - you then need an instrument to interpret the signal and provide you with the data as you have asked for it. For example a sensor does not tell you "how it looks"... that is the instrument's job.

Based on your language - it seems you are suspecting the utility, or the meter itself to be at fault

thanks

 

[CWatters]

In the UK you can buy devices to monitor domestic electricity use. They come in two parts connected by a wireless link. One part is a small display, the other is a clip on sensor. The clip on sensor must be attached to a single core wire so it's usually installed in the meter cabinet. No special skills are required to fit the sensor - just follow the instructions supplied with the kit. The down side is they aren't particularly accurate.

 

[anorlunda]

But the OP didn't ask about power, he asked about current. He also wanted the shape of the waveform. We can only guess at his intent.

If they sell inaccurate power sensors in the UK to monitor the service entrance, I foresee lots of unjustified disputes with the power company.

 

[mfb]

But the OP didn't ask about power, he asked about current. He also wanted the shape of the waveform. We can only guess at his intent.

Those sensors are actually measuring current only, they infer power from the voltage and some assumption about phase shift - with a single wire they have no proper access to it.

 

[Jeff Rosenbury]

From the meter the power feed will go to the main breaker box. There the wires are more accessible. (By the electrician. I'm an EE and I don't mess with the breaker box. Leave it to professionals. One obscure mistake and your house burns down in the middle of the night with your family in it.)

The simplest way would be to measure the voltage across an inserted shunt resistance with a logging digital scope, then transmit the images to your computer. (Bluetooth, perhaps.) This should give you a clear picture of the current.

Or I could tell you what it looks like. It's a sin wave.

I assume you are looking for something odd. But whatever it is, it is likely small in comparison to the main power wave. Unless it's a significant power draw, its effects will likely be under the noise floor.

This will include some noise from every source in your house, and your neighbors' houses. (These will slightly affect the voltage, which in turn affects the current in your house.)

They do make power quality monitors which look for odd sorts of problems. Perhaps one of these will work for you.

 

[NascentOxygen]

By "shape of the electrical signal each second" I would proceed on the basis that OP intends for the current's amplitude to be sampled every second, and ask clarifying questions accordingly.

 

[mfb]

Sampling the current current (...) once per second won't give anything interesting with 50 or 60 oscillations in between. You would need a much higher sampling rate to see anything. Averaging I² over a second to produce one reading per second would be a bit more interesting. But then the phase issue is still there.

 

[NascentOxygen]

Phase angle need not always be a crucial factor, e.g., if wishing to determine how close to tripping the breakers is a household's pattern of electricity usage, to see whether they need an additional circuit.

 

[CWatters]

But the OP didn't ask about power, he asked about current. He also wanted the shape of the waveform. We can only guess at his intent.

If they sell inaccurate power sensors in the UK to monitor the service entrance, I foresee lots of unjustified disputes with the power company.

They measure the current but assume the voltage is some nominal value which is why they aren't very accurate.